text:
Talk:Hull (watercraft)

Most central concept?
"single most central" concept? I think that phrase needs attention, but I don't know what to change it to. --KQ

Rafts and logs
Do rafts and single logs not constitute hulls? Even if not, the distinction is artificial, and they deserve mention IMO.

Hmm, swamps, roaring streams, and even calm streams where sharp objects and ankle-twisting holes are hard to spot, are more safely crossed by walking on logs. So as long as water levels vary enough, you don't need be swept into a river and save yourself by grabbing a floating log to think of a floating log as something for a person to float on. (Perhaps floating a carcass across a water barrier on a log or raft is more innovative than personal transport by water.) --Jerzy(t) 16:29, 2005 Feb 14 (UTC)

"Hull" is related to hell and concepts of hiding, and also means the outer layer of something. "Hollow" relates to "hole". So it is probably a linguistic coincidence that hulls, as floating structures, have to be hollow (to "trap ... air" -- not a very clearly stated concept, BTW, in the case of open boats) when made of heavier-than-water materials.

As to logs and rafts, the only reason that wood and foam are significantly lighter than water is is that both of them trap air in sealed capillaries or crevices, and in bubbles. They aren't "hulls" in being necessarily shell- or cowl-shaped, but they are hollow at a micro-scale. --Jerzy(t) 16:45, 2005 Feb 14 (UTC)

Mergefrom Displacement hull
Totally agree! P199 14:07, 20 March 2006 (UTC)

 * Merged. CP/M 02:05, 7 April 2006 (UTC)

 * Thanks! Ewlyahoocom 06:07, 7 April 2006 (UTC)

This Article Attempts Too Much
I'm not really sure what is intended by the discussion on "the class of shapes" ... hulls come in many varieties but are grouped primarily as follows:
 * Moulded, round bilged or soft-chined
 * Chined or Hard-chined

After this they can be categorized as:
 * Displacement
 * Semi-Planing
 * Planing

The discussion on bulbs (note that there are bow and stern bulbs)has merit and should be retained as it is a prominent feature of modern ship forms.

The section on hull metrics needs to be merged completed and clarified. So far only Block & Prismatic (Cb & Cp) are covered.
 * Block Measures (LOA, LWL, Bmax, Mmld, d or T and D)
 * Form derivatives (LCB, VCB, LCF, TPI, MCT, KMt KMl)
 * Coefficients (Cb, Cm or Cx & Cp)

The section on bouyancy should be retained (it is afterall, the main reason for the hull) The historical bits should be collected into and Origins section.

A series of images would help this article a lot.

Please advise if there is any objection to re-working this article as noted.

Jmvolc 00:49, 18 May 2006 (UTC)

 * It seems just the right way for the article, so reworking would be really useful. CP/M 22:28, 21 May 2006 (UTC)

Please don't forget that we have a lot of "general" readers, and that not everone who is going to be reading this article is a shipbuilder, a sailor, or even have ever been on a ship. Ewlyahoocom 23:37, 21 May 2006 (UTC)
 * The current definition of block coefficient is more confusing than the one on the previous page. Take for example:
 * " Block Coefficient (Cb) is the volume (&nabla) divided by the LWL x BWL x T."
 * What does this mean? Kablammo 23:56, 24 May 2006 (UTC)

 * Added a simpler explanation, and restored the old section. The new part is good, but it's quite technical and requires attention to comprehend. CP/M 00:05, 25 May 2006 (UTC)

The subjects addressed in this article are by their very nature quite techincal. The information provided is techically correct but may not be descriptive enough for the "general reader". Should more text/digrams be added to improve enhance comprehension?

My apologies for the &nabla term - I read that this in the Wikipedia Tutorial that it was to display the appropriate Greek character for Volume but alas, it did not. As described, Block Coeff is the displaced volume defined by the hull divided by the ecompassing block (LWL x BWL x draft). I could provide a diagram that may help, please advise if this should be added.

I have delete a significant portion of the Features section as the descriptions were at best over-generalizations and at worst, just wrong. Hopefully I have not offended. I can provide a more detailed explanation if required. Jmvolc 01:36, 27 May 2006 (UTC)

 * I agree, this article should be aimed primarily on technical details, but they still may be described in a simpler way along with the technical one. Coefficients can be provided with a direct description (for instance, the second external link has some). I've just added descriptions there, along with some correction, and will add now to some others, but adding some diagrams would be nice.

Planing
The page currently states that planing results from dynamic lift at speed, and in turn defines dynamic lift as "the upward force generated by the water as the hull moves through it". Is this correct? Why would the water generate any upward force beyond that necessary to float the hull? Or is planing a reaction to downward force exerted by water deflected downward by the shape of the hull? Are there any physicists out there who can clarify this? Kablammo 01:49, 1 June 2006 (UTC)

 * I'll see about how to explain more clearly in the article, but...
 * There are two types of force the water can provide. Buoyancy, which is the displaced weight of water, and dynamic lift, which is similar to the lift that you get from moving an airplane wing through air.  Buoyancy is always there.  Dynamic lift is only there while you're moving, because you're moving.  As dynamic lift increases, the boat moves up, and buoyancy decreases (more of the weight is being taken by the planing dynamic lift).
 * Does this help? Georgewilliamherbert 02:08, 1 June 2006 (UTC)

It does. What I questioned was the statement that the water generates an upward force. I would have thought that the water does nothing beyond float the boat. I'm also not sure about the airplane wing analogy-- I had understood that lift on a wing results from decreased pressure on the top surface of the wing. Does that apply here? Kablammo 02:42, 1 June 2006 (UTC)

 * Let me slip in a comment here--lift results not from decreased pressure, but rather from the deflection of the fluid through which the foil is passing. Any shape that deflects the fluid, including a flat plate, will generate lift; in the case of a flat plate (fluid flow direction ->  \ <- angled plate) the bottom of the plate will push the fluid down, generating lift.  The flow over the top of the plate will immediately stall out and swirl, slowing the fluid flow and causing drag; the low pressure on the back side will also cause the flow around the aft edge of the plate to be sucked back up, canceling out a good portion of the lift.  The suction does have an impact, but it's as a mechanism for deflecting the air efficiently.  The "suction causes lift" argument is hard to counter, since it is so entangled with the airflow deflection, but it's still Newton's third law that's really doing the work.

 * The lift on a planing hull is a case where the action/reaction explanation of lift works, but the suction explanation does not, since there is fluid flow on only one side of the hull (we'll ignore the air, it's 1000x less dense and has very little impact). A planing hull deflects the water primarily down (again, fluid flow direction-> \ <- angled plate) and this action pushes the hull upwards.  Calculate the mass of water displaced by the hull, the acceleration required to move that mass of water out of the way, and you get the amount of lift on the hull (forcer = mass * acceleration).  As the hull lifts up, the amount of water displaced is reduced, until an equilibrium between lift and displacement is reached, and then you're planing.  Since nearly all hulls (except a submerged submarine's) are going to push more water down than up, all hulls will generate some planing force, but wide, flat bottomed hulls will push the largest fraction of water down, and will thus generate the maximum lift for planing.  scot 14:34, 1 June 2006 (UTC)

 * The dynamic lift works pretty much the same as with aircraft's wing. A hydrostatical or hydrodynamical force applied to surface always acts normally to it. When the ship is moving, the resistance force, oriented horizontally ( -- ), is generated . If the bottom is placed upwards at the bow (like / ), the force acts normally to it ( \ ). It may be divided into backwards and upwards components. The backwards one counters the propulsion force, and the upwards gravity force, thus lifting the ship.
 * Comparing to the airplane wing: the pressure on top surface there is decreased; however, a ship has the same situation, with almost no upwards pressure at all, as air generates much less dynamic force than water.
 * CP/M 02:45, 1 June 2006 (UTC)

So if I read this correctly, then the water does not generate a force (as stated in the main page), but is directed by the moving hull to create an upward force? Could I suggest that one of you technical folks clarify the main page here? There is more technical description of planing, not in the currently-linked page on planing, but on the Planing (sailing) page. Perhaps that should be directly linked here. That would leave this article as a good general entry, with the technical explanation in the planing article. Kablammo 14:07, 1 June 2006 (UTC)

You are of course correct. Static water is no more capable of "generating" a dynamic force than it is of dancing a waltz. A more accurate description would be paraphrased from SNAME's "Principles of Naval Architecture" ... The Planing Hull form is configured to develop positive dynamic pressure so that its draft decreases with increasing speed.

I have modified the text to suit. Jmvolc 22:26, 5 June 2006 (UTC)

 * Thank you. I in turn have deleted the definition of semi-planing, as it did not conform to your improved wording and seems self-explanatory anyway. Kablammo 00:05, 6 June 2006 (UTC)

I would like to reinstate the semi-planing definition. It is a recognized category of hull type, I will change the definition to fall in line with the planing definition. Jmvolc 01:36, 6 June 2006 (UTC)

I would like to propose a seperate page for planing hulls as there are so many varients of this hull, it deserves a page by itself to discuss it. For example: deep Vee planing hulls stepped planing hulls warped planing hulls prismatic planing hulls

Then there are varity of detailed features of planing hulls that warrant discussion: spray strakes chines Deadrise angle

Also it would be worthwhile mentioning some of the great pioneers in the development of planing hulls. People Like Renato Sonny Levi, Daniel Savitsky and others. I am happy to cooperate with this forum to setup such a page. --41.133.242.224 (talk) 17:01, 5 September 2011 (UTC) Dr. Gunther Migeotte gmroaming@gmail.com

Wave piercing?
Wave-piercingwould seem to warrant inclusion. See HSV-2 Swift, Incat and Earthrace

 * Wave piercing hull forms are a distinct variant of the displacement form. I feel it belongs in its own entry as people will inevitably search for that term (ie: “wave piercing�?) and that if included here would open the door for the inclusion of many other variants (catamarans, trimarans, sea sled, barge, double-ended, etc.) Jmvolc 12:24, 12 August 2006 (UTC)

Merge in Draft (nautical)
Jmvolc 12:29, 12 August 2006 (UTC)
 * Oppose - I don't think it is appropriate to merge Draft (nautical) in here. The draft may measure the clearance required for the hull, but The air draft is a measure of the clearance required above the waterline (under bridges, through tunnels, etc.). A better option would be to make more of the article, in my opinion. -- Ratarsed 08:38, 28 July 2006 (UTC)
 * Oppose - Draft is a separate term, also per Ratarsed. CP/M (Wikipedia Neutrality Project) 08:42, 28 July 2006 (UTC)
 * Oppose - Draft is already defined here, the Draft (nautical) entry expands on the definition and adds value. I would suggest adding the following to the Draft (nautical) article"
 * Draft Marks
 * an image to show "draft" and one to show "draft marks"
 * text on the difference between max draft (the draft to the lowest point on the ship) and hull draft (usually used to compute hydrostatics.

Form Coefficients
Some of the descriptions and formulas given under Coefficients are incorrect. For example, are coefficients are based on measures on the design WL (LWL, BWL). Additionally, the text describing the influence of the various coefficients is probably better suited to be relocated to its own article on ship motions. These changes will be made shortly unless there is any objection. Jmvolc 01:45, 5 April 2007 (UTC)
 * Objection: I don't know what source you're using, but mine is the late 1980s (latest) edition of "Principles of Naval Architecture", and as I recall it defines the block, prismatic, and waterplane coefficients relating to length between perpendiculars (Lpp) not Lwl. Your source is... ? Georgewilliamherbert 03:14, 5 April 2007 (UTC)
 * (followup) Yes, I know you're a practicing NA and I'm not, though I have the degree, but can you recheck the PNA first? I will as well.  Georgewilliamherbert 03:16, 5 April 2007 (UTC)

 * I added citation and consulted Rawson&Tupper, and note it specifies LWL for Cwp, LPP for Cp and Cb...I recommend these forms--Billymac00 (talk) 04:12, 16 February 2008 (UTC)

It was not my intention to detract from the contributions you have made. An open discussion of this nature is very worthwhile and key to assuring that the article is based on fact, not opinion. LBP is an arbitrary number as the Aft Perpendicular is alternately defined as the forward edge of center of the rudder stock depending on your reference. Neither of these positions have anything to do with the actual form of the hull.

Principles of Naval Architecture is a good reference. Volume 1, Page 18 of the 1988 edition states that "Some authorities take L as LBP some as LWL, and some as effective length." The authorities referred to are primarily classification societies that also use Lr or Rule Length when calculating form coefficients. Given that the article is about defining the hull in general terms I thought it would be wise to follow the guidelines set out by Saunders in "Hydrodynamics in Ship Design" back in 1957. This definition is still used by the ITTC, etc. for definitions of form. Let me know if this works for you. Jmvolc 12:30, 6 April 2007 (UTC)

Depth
Metrics includes the following definition of Depth (D):
 * Depth (D) is the vertical distance from the bottom of the hull to the uppermost edge at the side.

This does not seem to fit well with whaleback ships and may not be applicable to all turret deck ships. Kablammo 16:08, 24 October 2007 (UTC)

 * That's the way it's defined, though. Georgewilliamherbert 02:04, 25 October 2007 (UTC)
 * That raises the question of what the uppermost edge at the side is on a turret or whaleback ship, which does not have an outside edge but only a curve where the gunwale normally would be found. Has the definition changed over time?  Kablammo 10:02, 25 October 2007 (UTC)
 * In turret deck ships the practice may have been inconsistent. A little book put out by the National Maritime Museum entitled Steam Tramps and Cargo Liners reproduces drawings from a paper by J. Foster King entitled Structural developments in British merchant ships from Transactions of the Institute of Naval Architects XLIX (1907), which show cross-sections of two turret deck ships.  The depth of SS Turret of 1892 apparently was measured from the bottom to the horizontal part of the "side" of the hull, that is, where the side curves to a horizontal plane before arcing back to vertical (there being no "edge" present).  SS Queda of 1905 however has two depth figures, one measured as in SS Turret, the other of which appears to be measured further inboard and higher, where the true deck meets the inboard and upper part of the "side" of the hull at right angles (and therefore forms an edge).  (Difficult to explain without a drawing.)  Perhaps the profession or rating authorities had difficulty applying standard definitions to these anomalous vessels.  Kablammo 12:27, 25 October 2007 (UTC)
 * Now answered, by reference to more refined definitions in 1969 convention. Kablammo 10:30, 27 October 2007 (UTC)

Air cavity hulls
Air cavity hulls aren't mentioned; see http://www.patentstorm.us/patents/6167829/description.html —Preceding unsigned comment added by 87.66.60.155 (talk) 11:44, 14 September 2009 (UTC)

Moulded breadth
Please define. Soerfm (talk) 21:31, 30 December 2011 (UTC)

Efficiency of planing hulls
Planing hulls are more efficient at higher speeds, although they still require more energy to achieve these speeds.

The phrase "more efficient" is typically defined as, "using less energy or fewer resources to achieve the same result." If a planing hull requires more energy to achieve a given speed than another type of hull, it is less efficient -- unless the author is using some non-standard definition of "more efficient." Either way, this sentence needs a rewrite to reduce confusion. GPS Pilot (talk) 15:15, 28 December 2012 (UTC)

 * A planing hull requires more power to initially get it up on the 'step' but once there requires less power for a given speed than a displacement hull does. Hence overall it is more efficient, due to less of the hull being 'wetted' and causing hydrodynamic drag. For this reason all flying boats and other seaplanes always have planing bottoms to their hulls or floats. OTOH, helicopters required to operate from water usually do not, having instead plain pontoons due to being able to take-off vertically. — Preceding unsigned comment added by 95.148.221.26 (talk) 12:34, 9 June 2015 (UTC)

Stepped Hull
I was reading the motorboat article and noticed a mention of the "first successful step hydroplane." Wondering what that was, I checked out hydroplane and found the term "stepped hull." The term stepped hull appears in Wikipedia quite a bit, but no one creates a link or attempts to explain what it means. I found a rather detailed article at Soundings Online titled "The Stepped Hull Has Come of Age". Perhaps someone could interpret this and add the concepts "stepped hull" and "unstepped hull" to the hull article, and then create articles on each? Someone could then create the links throughout Wikipedia. I barely understand the step concept and figure someone with nautical experience should write those.

I write history articles for a blog about Matawan and Aberdeen NJ USA and am looking at a front page article in the 26 June 1913 edition of The Matawan Journal referencing a "crazy speed boat" being designed by an Allie Haviland of Red Bank, NJ. The boat was expected to exceed fifty miles an hour and be the first of its kind when it was launched. The boat would have an eight-cylinder 60 HP engine. Any thoughts on that would be of interest to me. Pnoble805 (talk) 05:14, 30 June 2013 (UTC)

 * A 'step' is a discontinuity in the hull line intended to allow air under the hull in order to break the suction holding the hull in the water. The step was invented by John Porte when he was designing a new hull for the Felixstowe F.1 flying boat in WW I, the step making take-off more easier than in previous hull designs which had difficulty breaking free of the water surface.

 * In a hydroplane the step allows the hull to rise more easily out of the water to the planing position, whereupon it is said to be 'on the step'.

 * A 'step' is most useful when operating on sheltered water where the water is flat calm, such as lakes or rivers, as opposed to the open sea, where the action of the waves tend to assist with breaking the water suction. — Preceding unsigned comment added by 95.148.221.26 (talk) 12:50, 9 June 2015 (UTC)

History section underdeveloped
I'm moving the History section upwards to its usual place in WP article structure. In the meantime it needs development and lacks references. User:HopsonRoad 10:37, 10 June 2017 (UTC)

Is this correct?
Guys, I’m not a native speaker. But is this sentence correct? “Above the hull is the superstructure and/or deckhouse, where present.” It doesn’t make any sense to me. --185.4.43.93 (talk) 08:40, 13 July 2018 (UTC)
 * It's certainly awkward, if logical. I've changed it to: "Atop the hull may be a deckhouse or some other form of superstructure, like a mast." Thanks for the tip. Of course, anyone may edit here, including you! Cheers, HopsonRoad (talk) 12:18, 14 July 2018 (UTC)

Which "Centaur" is being referenced?
In the Smooth curve hulls section, a ship called the "Centaur" is said to have a semi-round bilge hull, with a link to the mythical creature. I am changing the link to Centaur (ship (disambiguation page) because there have been multiple ships called "Centaur" and I don't know which one is being referenced. Does anyone know which Centaur ship has a semi-round bilge hull? --LiamM32 (talk) 08:20, 11 February 2021 (UTC)

title: Talk:Hull (watercraft)


text:
Hydrofoil

A hydrofoil is a lifting surface, or foil, that operates in water. They are similar in appearance and purpose to aerofoils used by aeroplanes. Boats that use hydrofoil technology are also simply termed hydrofoils. As a hydrofoil craft gains speed, the hydrofoils lift the boat's hull out of the water, decreasing drag and allowing greater speeds.

Description
The hydrofoil usually consists of a winglike structure mounted on struts below the hull, or across the keels of a catamaran in a variety of boats (see illustration). As a hydrofoil-equipped watercraft increases in speed, the hydrofoil elements below the hull(s) develop enough lift to raise the hull out of the water, which greatly reduces hull drag. This provides a corresponding increase in speed and fuel efficiency.

Wider adoption of hydrofoils is prevented by the increased complexity of building and maintaining them. Hydrofoils are generally prohibitively more expensive than conventional watercraft above a certain displacement, so most hydrofoil craft are relatively small, and are mainly used as high-speed passenger ferries, where the relatively high passenger fees can offset the high cost of the craft itself. However, the design is simple enough that there are many human-powered hydrofoil designs. Amateur experimentation and development of the concept is popular.

Hydrodynamic mechanics

Since air and water are governed by similar fluid equations—albeit with different levels of viscosity, density, and compressibility—the hydrofoil and airfoil (both types of foil) create lift in identical ways. The foil shape moves smoothly through the water, deflecting the flow downward, which, following the Euler equations, exerts an upward force on the foil. This turning of the water creates higher pressure on the bottom of the foil and reduced pressure on the top. This pressure difference is accompanied by a velocity difference, via Bernoulli's principle, so the resulting flow field about the foil has a higher average velocity on one side than the other.

When used as a lifting element on a hydrofoil boat, this upward force lifts the body of the vessel, decreasing drag and increasing speed. The lifting force eventually balances with the weight of the craft, reaching a point where the hydrofoil no longer lifts out of the water but remains in equilibrium. Since wave resistance and other impeding forces such as various types of drag (physics) on the hull are eliminated as the hull lifts clear, turbulence and drag act increasingly on the much smaller surface area of the hydrofoil, and decreasingly on the hull, creating a marked increase in speed.

Foil configurations
Early hydrofoils used V-shaped foils. Hydrofoils of this type are known as "surface-piercing" since portions of the V-shape hydrofoils rise above the water surface when foilborne. Some modern hydrofoils use fully submerged inverted T-shape foils. Fully submerged hydrofoils are less subject to the effects of wave action, and, therefore, more stable at sea and more comfortable for crew and passengers. This type of configuration, however, is not self-stabilizing. The angle of attack on the hydrofoils must be adjusted continuously to changing conditions, a control process performed by sensors, a computer, and active surfaces.

Prototypes
The first evidence of a hydrofoil on a vessel appears on a British patent granted in 1869 to Emmanuel Denis Farcot, a Parisian. He claimed that "adapting to the sides and bottom of the vessel a series or inclined planes or wedge formed pieces, which as the vessel is driven forward will have the effect of lifting it in the water and reducing the draught.". Italian inventor Enrico Forlanini began work on hydrofoils in 1898 and used a "ladder" foil system. Forlanini obtained patents in Britain and the United States for his ideas and designs.

Between 1899 and 1901, British boat designer John Thornycroft worked on a series of models with a stepped hull and single bow foil. In 1909 his company built the full scale 22 ft long boat, Miranda III. Driven by a 60 hp engine, it rode on a bowfoil and flat stern. The subsequent Miranda IV was credited with a speed of 35 kn.

In May 1904 a hydrofoil boat was described being tested on the River Seine "in the neighbourhood of Paris". This boat was designed by Comte de Lambert. This had 5 variable pitch fins on the hull beneath the water so inclined that when the boat begins to move "the boat rises and the planes come to the surface" with the result that "it skims over the surface with little but the propellers beneath the surface". The boat had twin hulls 18-foot long connected by a single deck 9-foot wide, and was fitted with a 14HP De Dion-Bouton motor, the boat was reported to have reached 20 mph. It was stated that "The boat running practically on its fins resembles an aeroplane".

A March 1906 Scientific American article by American hydrofoil pioneer William E. Meacham explained the basic principle of hydrofoils. Alexander Graham Bell considered the invention of the hydroplane (now regarded as a distinct type, but also employing lift) a very significant achievement, and after reading the article began to sketch concepts of what is now called a hydrofoil boat. With his chief engineer Casey Baldwin, Bell began hydrofoil experiments in the summer of 1908. Baldwin studied the work of the Italian inventor Enrico Forlanini and began testing models based on those designs, which led to the development of hydrofoil watercraft. During Bell's world tour of 1910–1911, Bell and Baldwin met with Forlanini in Italy, where they rode in his hydrofoil boat over Lake Maggiore. Baldwin described it as being as smooth as flying.

On returning to Bell's large laboratory at his Beinn Bhreagh estate near Baddeck, Nova Scotia, they experimented with a number of designs, culminating in Bell's HD-4. Using Renault engines, a top speed of 87 km/h was achieved, accelerating rapidly, taking waves without difficulty, steering well and showing good stability. Bell's report to the United States Navy permitted him to obtain two 260 kW (350 hp) engines. On 9 September 1919 the HD-4 set a world marine speed record of 114 km/h, which stood for two decades. A full-scale replica of the HD-4 is viewable at the Alexander Graham Bell National Historic Site museum in Baddeck, Nova Scotia.

In the early 1950s an English couple built the White Hawk, a jet-powered hydrofoil water craft, in an attempt to beat the absolute water speed record. However, in tests, White Hawk could barely top the record breaking speed of the 1919 HD-4. The designers had faced an engineering phenomenon that limits the top speed of even modern hydrofoils: cavitation disturbs the lift created by the foils as they move through the water at speed above 60 kn, bending the lifting foil.

First passenger boats
German engineer Hanns von Schertel worked on hydrofoils prior to and during World War II in Germany. After the war, the Russians captured Schertel's team. As Germany was not authorized to build fast boats, Schertel went to Switzerland, where he established the Supramar company. In 1952, Supramar launched the first commercial hydrofoil, PT10 "Freccia d'Oro" (Golden Arrow), in Lake Maggiore, between Switzerland and Italy. The PT10 is of surface-piercing type, it can carry 32 passengers and travel at 35 kn. In 1968, the Bahraini born banker Hussain Najadi acquired the Supramar AG and expanded its operations into Japan, Hong Kong, Singapore, the UK, Norway and the US. General Dynamics of the United States became its licensee, and the Pentagon awarded its first R&D naval research project in the field of supercavitation. Hitachi Shipbuilding of Osaka, Japan, was another licensee of Supramar, as well as many leading ship owners and shipyards in the OECD countries.

From 1952 to 1971, Supramar designed many models of hydrofoils: PT20, PT50, PT75, PT100 and PT150. All are of surface-piercing type, except the PT150 combining a surface-piercing foil forward with a fully submerged foil in the aft location. Over 200 of Supramar's design were built, most of them by Rodriquez (headed at the time by Engineer Carlo Rodriquez in Sicily, Italy.

During the same period the Soviet Union experimented extensively with hydrofoils, constructing hydrofoil river boats and ferries with streamlined designs during the cold war period and into the 1980s. Such vessels include the Raketa (1957) type, followed by the larger Meteor type and the smaller Voskhod type. One of the most successful Soviet designer/inventor in this area was Rostislav Alexeyev, who some consider the 'father' of the modern hydrofoil due to his 1950s era high speed hydrofoil designs. Later, circa 1970s, Alexeyev combined his hydrofoil experience with the surface effect principle to create the Ekranoplan. Extensive investment in this type of technology in the USSR resulted in the largest civil hydrofoil fleet in the world and the making of the Meteor type, the most successful hydrofoil in history, with more than 400 units built.

In 1961, SRI International issued a study on "The Economic Feasibility of Passenger Hydrofoil Craft in US Domestic and Foreign Commerce". Commercial use of hydrofoils in the US first appeared in 1961 when two commuter vessels were commissioned by Harry Gale Nye, Jr.'s North American Hydrofoils to service the route from Atlantic Highlands, New Jersey to the financial district of Lower Manhattan.

Germany
A 17-ton German craft VS-6 Hydrofoil was designed and constructed in 1940, completed in 1941 for use as a mine layer,;it was tested in the Baltic Sea, producing speeds of 47 knots. Tested against a standard E-boat over the next three years it performed well but was not brought into production. Being faster it could carry a higher payload and was capable of travelling over minefields but was prone to damage and noisier.

Canada
In Canada during World War II, Baldwin worked on an experimental smoke laying hydrofoil (later called the Comox Torpedo) that was later superseded by other smoke-laying technology and an experimental target-towing hydrofoil. The forward two foil assemblies of what is believed to be the latter hydrofoil were salvaged in the mid-1960s from a derelict hulk in Baddeck, Nova Scotia by Colin MacGregor Stevens. These were donated to the Maritime Museum in Halifax, Nova Scotia.

The Canadian Armed Forces built and tested a number of hydrofoils (e.g., Baddeck and two vessels named Bras d'Or), which culminated in the high-speed anti-submarine hydrofoil HMCS Bras d'Or in the late 1960s. However, the program was cancelled in the early 1970s due to a shift away from anti-submarine warfare by the Canadian military. The Bras d'Or was a surface-piercing type that performed well during her trials, reaching a maximum speed of 63 kn.

Soviet Union
The USSR introduced several hydrofoil-based fast attack craft into their navy, principally:
 * Sarancha class missile boat, a unique vessel built in the 1970s
 * Turya class torpedo boat, introduced in 1972 and still in service
 * Matka class missile boat, introduced in the 1980s and still in service
 * Muravey class patrol boat, introduced in the 1980s and still in service

United States
The US Navy began experiments with hydrofoils in the mid-1950s by funding a sailing vessel that used hydrofoils to reach speeds in the 30 mph range. The XCH-4 (officially, Experimental Craft, Hydrofoil No. 4), designed by William P. Carl, exceeded speeds of 65 mph and was mistaken for a seaplane due to its shape.

The US Navy implemented a small number of combat hydrofoils, such as the Pegasus class, from 1977 through 1993. These hydrofoils were fast and well armed.

Italy
The Italian Navy used six hydrofoils of the Sparviero class starting in the late 1970s. These were armed with a 76 mm gun and two missiles, and were capable of speeds up to 50 kn. Three similar boats were built for the Japan Maritime Self-Defense Force.

Sailing and sports
Several editions of the America's Cup have been raced with foiling yachts. In 2013 and 2017 respectively the AC72 and AC50 classes of catamaran, and in 2021 the AC75 class of foiling monohulls with canting arms.

The French experimental sail powered hydrofoil Hydroptère is the result of a research project that involves advanced engineering skills and technologies. In September 2009, the Hydroptère set new sailcraft world speed records in the 500 m category, with a speed of 51.36 knot and in the 1 nmi category with a speed of 50.17 knot.

The 500 m speed record for sailboats is currently held by the Vestas Sailrocket, an exotic design which operates in effect as a hydrofoil.

Another trimaran sailboat is the Windrider Rave. The Rave is a commercially available 17 ft, two person, hydrofoil trimaran, capable of reaching speeds of 40 kn. The boat was designed by Jim Brown.

The Moth dinghy has evolved into some radical foil configurations.

Hobie Sailboats produced a production foiling trimaran, the Hobie Trifoiler, the fastest production sailboat. Trifoilers have clocked speeds upward of thirty knots.

A new kayak design, called Flyak, has hydrofoils that lift the kayak enough to significantly reduce drag, allowing speeds of up to 27 km/h. Some surfers have developed surfboards with hydrofoils called foilboards, specifically aimed at surfing big waves further out to sea.

Quadrofoil Q2 is a two-seater, four-foiled hydrofoil electrical leisure watercraft. Its initial design was set in 2012 and it has been available commercially since the end of 2016. Powered by a 5.2-kWh lithium-ion battery pack and propelled by a 5.5 kW motor, it reaches the top speed of 40 km/h and has 80 km of range.

The Manta5 Hydrofoiler XE-1 is a Hydrofoil E-bike, designed and built in New Zealand that has since been available commercially for pre-order since late 2017. Propelled by a 400 watt motor, it can reach speeds exceeding 14 km/h with a weight of 22 kg. A single charge of the battery lasts an hour for a rider weighing 85 kg.

Candela, a Swedish company, is producing a recreational hydrofoil powerboat, making strong claims for efficiency, performance, and range.

Hydrofoils are now widely used with kitesurfing, that is traction kites over water. Hydrofoils are a new trend in windsurfing - including the new Summer Olympic class, the IQFoil,  and more recently with Wing foiling,  which are essentially a kite with no strings, or a hand-held sail.

Modern passenger boats

Soviet-built Voskhods are one of the most successful passenger hydrofoil designs. Manufactured in Soviet and later Ukrainian Crimea, they are in service in more than 20 countries. The most recent model, Voskhod-2M FFF, also known as Eurofoil, was built in Feodosiya for the Dutch public transport operator Connexxion.

Mid-2010s saw a Russian governmental program aimed at restoring passenger hydrofoil production. The Kometa 120M, based on the earlier Kometa, Kolhida and Katran models, became the first to enter production, initially on Vympel (Rybinsk) factory in Rybinsk, and later on More shipyard in Feodosiya. Since 2018, the ships are running Sevastopol-Yalta and Sochi-Gelenzhik-Novorossiysk, with a Sevastopol-Sochi connection in the immediate plans in 2021. At the same time, the Alekseyev Bureau began building lighter, smaller Valday 45R hydrofoils, based on a widely successful Polesye (hydrofoil) model, at its own plant in Nizhny Novgorod, the relatively shallow-draft boats used on the Ob and the Volga. The Meteor 120R, a development of the Meteor (hydrofoil), became the Valday's larger sibling, the first ship launched in Nizhny Novgorod in August 2021.

The Boeing 929 is widely used in Asia for passenger services, between Hong Kong and Macau and between the many islands of Japan, also on the Korean peninsula. The main user is Hong Kong private corp.

Current operation
Current operators of hydrofoils include:

 * TurboJET service, which speeds passengers across the Pearl River Delta between Hong Kong and Macau in less than an hour, with an average speed of 45 knots (83 km/h), mainly using Boeing's Jetfoil. Also services Shenzhen, Panyu (Nansha) and Kowloon. Operated by Shun Tak-China Travel Ship Management Limited.
 * Voskhod and Polesye service between Tulcea and Sulina on the Danube.
 * Meteor and Polesye service in Poland between Szczecin and Świnoujście.
 * Cometa service between Nizhneangarsk and Irkutsk on Lake Baikal.
 * Cometa service between Vladivostok and Slavyanka.
 * Polesye service between Mozyr and Turov on the Pripyat River (Belarus).
 * Meteor service between Saint Petersburg, Russia and the Peterhof Palace, a summer palace of Russian tsars.

Currently, the main hydrofoil operator in Italy is Liberty Lines, which operates connections between the smaller Sicilian islands with Sicily and Calabria and between Trieste and some towns on the Croatian coast. SNAV operates connections between Naples and the smaller Campanian islands and - in the summer period - between Naples and the Aeolian Islands. In summer, Aliscost operates a connection between Salerno and some coastal towns of Campania and the Aeolian Islands.
 * Meteor service between Saint Petersburg, Russia and the Kronstadt, a strongly fortified Russian seaport town, located on Kotlin Island, near the head of the Gulf of Finland. It lies thirty kilometers west of Saint Petersburg. Since 2012 replaced by a catamaran Mercury.
 * Meteor, Raketa and Voskhod hydrofoil types operate all over Volga, Don and Kama Rivers in Russia. Also the Lena River and Amur River.
 * Meteor hydrofoils are operated by a number of tour operators in Croatia, mostly for packaged tours, but there are also some scheduled services to islands in Adriatic.
 * Hydrofoils are regularly operated on the three major Italian lakes by branches of the Ministry of Infrastructure and Transport: Navigazione Lago Maggiore services routes on Lake Maggiore between Locarno and Arona, Navigazione Lago di Como services routes on Lake Como, and Navigazione Lago di Garda services routes on Lake Garda. Three units of the Rodriguez RHS150 type operate on each lake, for a total of nine hydrofoils.
 * Former Russian hydrofoils are used in southern Italy for connection with islands of Lazio and Campania. SNAV has five RHS200, RHS160 and RHS150 used in the connections between Naples and the islands of Capri and Ischia.
 * A regular hydrofoil service runs from Istanbul to Yalova.
 * Hellenic Seaways operate their Flying Dolphins service over many routes in the Aegean, between the Cyclades, Saronic Gulf islands such as Aegina and Poros, and Athens.
 * Meteor (2), Polesye (4) and Voskhod (3) hydrofoil types operate in Hungary. MAHART PassNave Ltd. operates scheduled hydrofoil liners between Budapest, Bratislava and Vienna, inland liners between Budapest and the Danube Bend, and theme cruises to Komárom, Solt, Kalocsa and Mohács.
 * "Kometa" Flying Dolphin services are currently operated by Joy Cruises between Corfu and Paxos. They run from Corfu Port to Gaios using two hydrofoils: Ilida and Ilida II. The company operates also an international service from Corfu to Saranda (Albania) using the hydrofoil Ilida Dolphin of the same type.
 * "Kometa" type hydrofoils (registered in Albania) are operated by Ionian Cruises and Finikas Lines between Saranda and Corfu.
 * Russian hydrofoils of the Kometa type operated on the Bulgarian Black Sea Coast connecting Varna, Nesebar, Burgas, Sozopol, Primorsko, and Tsarevo, and Raketa and Meteor models served the Bulgarian Danube ports between Rousse and Vidin. Both services were discontinued in the 1990s. In 2011 the service reopened between Varna, Nesebar, Burgas and Sozopol, operated by Bulgarian Hydrofoils Ltd.
 * Vietnamese Greenline Company operates hourly shuttle service between Ho Chi Minh City, Vung Tau and Con Dao island. Hydrofoil lines using the Russian-built Meteor type also connect Hai Phong, Ha Long and Mong Cai in North Vietnam, Phan Thiet and Phu Quy Island and between Rach Gia and Phu Quoc Island in the South.
 * The service between Busan, South Korea and Fukuoka, Japan is operated by two companies. Japanese JR Kyūshū Jet Ferry operates Beetle five times a day. Korean Miraejet operates Kobee three to four times a day. All of their fleets are Boeing 929.
 * As of February 2008, all of the commercial lines in Japan use Boeing 929. The routes include:
 * Sado Kisen operates the route between Sado and Niigata.
 * Tōkai Kisen operates Seven Islands, running between Tokyo and Izu Islands, via Tateyama or Yokosuka. The destinations include Izu Ōshima, Toshima, Niijima, Shikinejima, and Kōzushima. The same ship also links Atami and Izu Ōshima.
 * Kyūshū Yūsen operates the route between Fukuoka, Iki, and the two ports of Tsushima.
 * Kyūshū Shōsen operates the route between Nagasaki and the two of Gotō Islands, namely Fukuejima and Nakadōrijima.
 * Kagoshima Shōsen and Cosmo Line operate the various routes between Kagoshima and Tanegashima or Yakushima.
 * In 2012, Agriculture, Fisheries and Conservation Department (AFCD) in Hong Kong leased a 12-meter HAWC (Hydrofoil Assisted Water Craft), a catamaran, to patrol the Hong Kong UNESCO Global Geopark in the Sai Kung Volcanic Rock Region.
 * In 2017, Voskhod boat began operating on 2 lines in Ukraine: Nova Kakhovka-Kherson-Hola Prystan, Mykolaiv-Kinburn Spit, Ochakiv-Kinburn Spit.
 * In July 2018, the new generation Kometa 120M boat has started operation on the busy Sevastopol-Yalta route in Crimea, with the plans to add two more and possible other routes in 2019.
 * In Italy hydrofoils have been used for commercial connections since 1956, by the Rodriguez shipyards and the SNAV company.

Discontinued operations

 * Until 31 December 2013, Fast Flying Ferries operated by Connexxion provided a regular public transport service over the North Sea Canal between Amsterdam Central Station and Velsen-Zuid in the Netherlands, using Voskhod 2M hydrofoils. It was stopped due to a new speed limit.
 * Between 1981 and 1990, Transmediterranea operated a service of hydrofoils connecting Ceuta and Algeciras in the Strait of Gibraltar. The crossing took half an hour, in comparison to the hour and a half of conventional ferries. Due to the common extreme winds and storms that take place in winter in the Strait of Gibraltar, the service was replaced in 1990 by catamarans, which were also able to carry cars. At the peak of the year, in summer, there was a service every half an hour in each direction. This high-speed connection had a big impact on the development of Ceuta, facilitating one-day business trips to mainland Spain.
 * Between 1964 and 1991 the Sydney hydrofoils operated on Sydney Harbour between Circular Quay and Manly.
 * Between 1969 and 1998 Red Funnel operated between Southampton and Cowes, Isle of Wight.
 * During the 1970s and 1980s there were frequent services between Belgrade and Tekija in Đerdap gorge. The distance of 220 km was covered in 3 hours and 30 minutes downstream and 4 hours upstream.
 * Between 1980 and 1981, B+I Line operated a Boeing 929 jetfoil, named Cú Na Mara (Hound of the Sea), between Liverpool and Dublin. The service was not successful and was discontinued at the end of the 1981 season.
 * Between the 1960s and 1985 there were hydrofoils going between Malmö, Sweden and Copenhagen, Denmark. They were retired and exchanged for catamarans. The service got cancelled when the Öresund Bridge got built in the early 2000s.
 * Condor Ferries operated six hydrofoil ferries over a 29-year period between the Channel Islands, the south coast of England and Saint-Malo in France.
 * Following the restoration of Estonian independence in the 1990s, the regular ferry service between Helsinki and Tallinn was augmented by Soviet built hydrofoils during the summer season in periods of good weather. The higher speed service competed with the traditional ro-ro ferries but allowed easy day trips for pedestrian travellers. They were ultimately replaced with high-speed catamarans that could also carry vehicles and have better seaworthiness; however, the latter ceased operations as the operator filed for bankruptcy in May 2018.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Hydrofoil


text:
Henri Chopin

Henri Chopin (18 June 1922 – 3 January 2008) was a French avant-garde poet and musician.

Life
Henri Chopin was born in Paris, 18 June 1922, one of three brothers, and the son of an accountant. Both his siblings died during the war. One was shot by a German soldier the day after an armistice was declared in Paris, the other while sabotaging a train.

Chopin was a French practitioner of concrete and sound poetry, well known throughout the second half of the 20th century. His work, though iconoclastic, remained well within the historical spectrum of poetry as it moved from a spoken tradition to the printed word and now back to the spoken word again. He created a large body of pioneering recordings using early tape recorders, studio technologies and the sounds of the manipulated human voice. His emphasis on sound is a reminder that language stems as much from oral traditions as from classic literature, of the relationship of balance between order and chaos.

Chopin is significant above all for his diverse spread of creative achievement, as well as for his position as a focal point of contact for the international arts. As poet, painter, graphic artist and designer, typographer, independent publisher, filmmaker, broadcaster and arts promoter, Chopin's work is a barometer of the shifts in European media between the 1950s and the 1970s.

In 1966 he was with Gustav Metzger, Otto Muehl, Wolf Vostell, Peter Weibel and others a participant of the Destruction in Art Symposium (DIAS) in London.

In 1964 he created OU, one of the most notable reviews of the second half of the 20th century, and he ran it until 1974. OU's contributors included William S. Burroughs, Brion Gysin, Gil J. Wolman, François Dufrêne, Bernard Heidsieck, John Furnival, Tom Phillips, and the Austrian sculptor, writer and Dada pioneer Raoul Hausmann.

His books included Le Dernier Roman du Monde (1971), Portrait des 9 (1975), The Cosmographical Lobster (1976), Poésie Sonore Internationale (1979), Les Riches Heures de l'Alphabet (1992) and Graphpoemesmachine (2006). Henri also created many graphic works on his typewriter: the typewriter poems (also known as dactylopoèmes) feature in international art collections such as those of Francesco Conz in Verona, the Morra Foundation in Naples and Ruth and Marvin Sackner in Miami, and have been the subject of Australian, British and French retrospectives.

His publication and design of the classic audio-visual magazines Cinquième Saison and OU between 1958 and 1974, each issue containing recordings as well as texts, images, screenprints and multiples, brought together international contemporary writers and artists such as members of Lettrisme and Fluxus, Jiri Kolar, Ian Hamilton Finlay, Tom Phillips, Brion Gysin, William S. Burroughs and many others, as well as bringing the work of survivors from earlier generations such as Raoul Hausmann and Marcel Janco to a fresh audience.

From 1968 to 1986 Henri Chopin lived in Ingatestone, Essex, but with the death of his wife Jean in 1985, he moved back to France.

In 2001 with his health failing, he returned to England, living with his daughter and family at Dereham, Norfolk until his death on 3 January 2008.

Aesthetics
Chopin's poesie sonore aesthetics included a deliberate cultivation of a barbarian approach in production, using raw or crude sound manipulations to explore the area between distortion and intelligibility. He avoided high-quality, professional recording machines, preferring to use very basic equipment and bricolage methods, such as sticking matchsticks in the erase heads of a second-hand tape recorder, or manually interfering with the tape path.

Books

 * Chopin, Henri. 1979. Poesie Sonore Internationale, edited by Jean-Michel Place. Paris: Trajectoires.

Films on Henri Chopin

 * De Henri à Chopin, le dernier pape by Frédéric Acquaviva and Maria Faustino, DV, 3h10mn, 2002–2008
 * Henri Chopin, reflecting on OU, by Silva Gabriela Béju, DV, 28', 2001, published in 2016 in "CRU"n°2 magazine (La Plaque Tournante, Berlin, dir. Frédéric Acquaviva and Loré Lixenberg)

Listening

 * UbuWeb Sound: Henri Chopin.

title: Henri Chopin


text:
Hassium

Hassium is a synthetic chemical element; it has symbol Hs and atomic number 108. Hassium is highly radioactive: its most stable known isotopes have half-lives of approximately ten seconds. One of its isotopes, 270Hs, has magic numbers of protons and neutrons for deformed nuclei, giving it greater stability against spontaneous fission. Hassium is a superheavy element; it has been produced in a laboratory in very small quantities by fusing heavy nuclei with lighter ones. Natural occurrences of the element have been hypothesised but never found.

In the periodic table of elements, hassium is a transactinide element, a member of the 7th period and group 8; it is thus the sixth member of the 6d series of transition metals. Chemistry experiments have confirmed that hassium behaves as the heavier homologue to osmium, reacting readily with oxygen to form a volatile tetroxide. The chemical properties of hassium have been only partly characterized, but they compare well with the chemistry of the other group 8 elements.

The principal innovation that led to the discovery of hassium was the technique of cold fusion, in which the fused nuclei did not differ by mass as much as in earlier techniques. It relied on greater stability of target nuclei, which in turn decreased excitation energy. This decreased the number of neutron ejections during synthesis, creating heavier, more stable resulting nuclei. The technique was first tested at the Joint Institute for Nuclear Research (JINR) in Dubna, Moscow Oblast, Russian SFSR, Soviet Union, in 1974. JINR used this technique to attempt synthesis of element 108 in 1978, in 1983, and in 1984; the latter experiment resulted in a claim that element 108 had been produced. Later in 1984, a synthesis claim followed from the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Hesse, West Germany. The 1993 report by the Transfermium Working Group, formed by the International Union of Pure and Applied Chemistry and the International Union of Pure and Applied Physics, concluded that the report from Darmstadt was conclusive on its own whereas that from Dubna was not, and major credit was assigned to the German scientists. GSI formally announced they wished to name the element hassium after the German state of Hesse (Hassia in Latin), home to the facility in 1992; this name was accepted as final in 1997.

Cold fusion
Nuclear reactions used in the 1960s resulted in high excitation energies that required expulsion of four or five neutrons; these reactions used targets made of elements with high atomic numbers to maximize the size difference between the two nuclei in a reaction. While this increased the chance of fusion due to the lower electrostatic repulsion between the target and the projectile, the formed compound nuclei often broke apart and did not survive to form a new element. Moreover, fusion processes inevitably produce neutron-poor nuclei, as heavier elements require more neutrons per proton to maximize stability; therefore, the necessary ejection of neutrons results in final products with typically have shorter lifetimes. As such, light beams (six to ten protons) allowed synthesis of elements only up to 106.

To advance to heavier elements, Soviet physicist Yuri Oganessian at the Joint Institute for Nuclear Research (JINR) in Dubna, Moscow Oblast, Russian SFSR, Soviet Union, proposed a different mechanism, in which the bombarded nucleus would be lead-208, which has magic numbers of protons and neutrons, or another nucleus close to it. Each proton and neutron has a fixed value of rest energy; those of all protons are equal and so are those of all neutrons. In a nucleus, some of this energy is diverted to binding protons and neutrons; if a nucleus has a magic number of protons and/or neutrons, then even more of its rest energy is diverted, which gives the nuclide additional stability. This additional stability requires more energy for an external nucleus to break the existing one and penetrate it. More energy diverted to binding nucleons means less rest energy, which in turn means less mass (mass is proportional to rest energy). More equal atomic numbers of the reacting nuclei result in greater electrostatic repulsion between them, but the lower mass excess of the target nucleus balances it. This leaves less excitation energy for the newly created compound nucleus, which necessitates fewer neutron ejections to reach a stable state. Because of this energy difference, the former mechanism became known as "hot fusion" and the latter as "cold fusion".

Cold fusion was first declared successful in 1974 at JINR, when it was tested for synthesis of the yet-undiscovered element   106. These new nuclei were projected to decay via spontaneous fission. The physicists at JINR concluded element 106 was produced in the experiment because no fissioning nucleus known at the time showed parameters of fission similar to what was observed during the experiment and because changing either of the two nuclei in the reactions negated the observed effects. Physicists at the Lawrence Berkeley Laboratory (LBL; originally Radiation Laboratory, RL, and later Lawrence Berkeley National Laboratory, LBNL) of the University of California in Berkeley, California, United States, also expressed great interest in the new technique. When asked about how far this new method could go and if lead targets were a physics' Klondike, Oganessian responded, "Klondike may be an exaggeration [...] But soon, we will try to get elements 107   ... 108 in these reactions."

Reports
The synthesis of element   108 was first attempted in 1978 by a research team led by Oganessian at the JINR. The team used a reaction that would generate element   108, specifically, the isotope 270108, from fusion of radium (specifically, the isotope ) and calcium. The researchers were uncertain in interpreting their data, and their paper did not unambiguously claim to have discovered the element. The same year, another team at JINR investigated the possibility of synthesis of element   108 in reactions between lead  and iron ; they were uncertain in interpreting the data, suggesting the possibility that element    108 had not been created.

In 1983, new experiments were performed at JINR. The experiments probably resulted in the synthesis of element   108; bismuth  was bombarded with manganese  to obtain 263108, lead  was bombarded with iron  to obtain 264108, and californium  was bombarded with neon  to obtain 270108. These experiments were not claimed as a discovery and Oganessian announced them in a conference rather than in a written report.

In 1984, JINR researchers in Dubna performed experiments set up identically to the previous ones; they bombarded bismuth and lead targets with ions of lighter elements manganese and iron, respectively. Twenty-one spontaneous fission events were recorded; the researchers concluded they were caused by 264108.

Later in 1984, a research team led by Peter Armbruster and Gottfried Münzenberg at Gesellschaft für Schwerionenforschung (GSI; Institute for Heavy Ion Research) in Darmstadt, Hesse, West Germany, attempted to create element   108. The team bombarded a lead target with accelerated iron  nuclei. GSI's experiment to create element   108 was delayed until after their creation of element    109 in 1982, as prior calculations had suggested that even–even isotopes of element    108 would have spontaneous fission half-lives of less than one microsecond, making them difficult to detect and identify. The element   108 experiment finally went ahead after 266109 had been synthesized and was found to decay by alpha emission, suggesting that isotopes of element    108 would do likewise, and this was corroborated by an experiment aimed at synthesizing isotopes of element    106. GSI reported synthesis of three atoms of 265108. Two years later, they reported synthesis of one atom of the even–even 264108.

Arbitration
In 1985, the International Union of Pure and Applied Chemistry (IUPAC) and the International Union of Pure and Applied Physics (IUPAP) formed the Transfermium Working Group (TWG) to assess discoveries and establish final names for elements with atomic numbers greater than 100. The party held meetings with delegates from the three competing institutes; in 1990, they established criteria for recognition of an element and in 1991, they finished the work of assessing discoveries and disbanded. These results were published in 1993.

According to the report, the 1984 works from JINR and GSI simultaneously and independently established synthesis of element   108. Of the two 1984 works, the one from GSI was said to be sufficient as a discovery on its own. The JINR work, which preceded the GSI one, "very probably" displayed synthesis of element   108. However, that was determined in retrospect given the work from Darmstadt; the JINR work focused on chemically identifying remote granddaughters of element   108 isotopes (which could not exclude the possibility that these daughter isotopes had other progenitors), while the GSI work clearly identified the decay path of those element    108 isotopes. The report concluded that the major credit should be awarded to GSI. In written responses to this ruling, both JINR and GSI agreed with its conclusions. In the same response, GSI confirmed that they and JINR were able to resolve all conflicts between them.

Naming
Historically, a newly discovered element was named by its discoverer. The first regulation came in 1947, when IUPAC decided naming required regulation in case there are conflicting names. These matters were to be resolved by the Commission of Inorganic Nomenclature and the Commission of Atomic Weights. They would review the names in case of a conflict and select one; the decision would be based on a number of factors, such as usage, and would not be an indicator of priority of a claim. The two commissions would recommend a name to the IUPAC Council, which would be the final authority. The discoverers held the right to name an element, but their name would be subject to approval by IUPAC. The Commission of Atomic Weights distanced itself from element naming in most cases.

Under Mendeleev's nomenclature for unnamed and undiscovered elements, hassium would be known as "eka-osmium", as in "the first element below osmium in the periodic table" (from Sanskrit eka meaning "one"). In 1979, IUPAC published recommendations according to which the element was to be called "unniloctium" and assigned the corresponding symbol of "Uno", a systematic element name as a placeholder until the element was discovered and the discovery then confirmed, and a permanent name was decided. Although these recommendations were widely followed in the chemical community, the competing physicists in the field ignored them. They either called it "element   108", with the symbols E108, (108) or 108, or used the proposed name "hassium".

In 1990, in an attempt to break a deadlock in establishing priority of discovery and naming of several elements, IUPAC reaffirmed in its nomenclature of inorganic chemistry that after existence of an element was established, the discoverers could propose a name. (In addition, the Commission of Atomic Weights was excluded from the naming process.) The first publication on criteria for an element discovery, released in 1991, specified the need for recognition by TWG.

Armbruster and his colleagues, the officially recognized German discoverers, held a naming ceremony for the elements 107 through 109, which had all been recognized as discovered by GSI, on 7   September 1992. For element   108, the scientists proposed the name "hassium". It is derived from the Latin name Hassia for the German state of Hesse where the institute is located. This name was proposed to IUPAC in a written response to their ruling on priority of discovery claims of elements, signed 29 September 1992.

The process of naming of element 108 was a part of a larger process of naming a number of elements starting with element 101; three teams—JINR, GSI, and LBL—claimed discoveries of several elements and the right to name those elements. Sometimes, these claims clashed; since a discoverer was considered entitled to naming of an element, conflicts over priority of discovery often resulted in conflicts over names of these new elements. These conflicts became known as the Transfermium Wars. Different suggestions to name the whole set of elements from 101 onward and they occasionally assigned names suggested by one team to be used for elements discovered by another. However, not all suggestions were met with equal approval; the teams openly protested naming proposals on several occasions.

In 1994, IUPAC Commission on Nomenclature of Inorganic Chemistry recommended that element   108 be named "hahnium" (Hn) after the German physicist Otto Hahn so elements named after Hahn and Lise Meitner (it was recommended element    109 should be named meitnerium, following GSI's suggestion) would be next to each other, honouring their joint discovery of nuclear fission; IUPAC commented that they felt the German suggestion was obscure. GSI protested, saying this proposal contradicted the long-standing convention of giving the discoverer the right to suggest a name; the American Chemical Society supported GSI. The name "hahnium", albeit with the different symbol Ha, had already been proposed and used by the American scientists for element   105, for which they had a discovery dispute with JINR; they thus protested the confusing scrambling of names. Following the uproar, IUPAC formed an ad hoc committee of representatives from the national adhering organizations of the three countries home to the competing institutions; they produced a new set of names in 1995. Element   108 was again named hahnium; this proposal was also retracted. The final compromise was reached in 1996 and published in 1997; element   108 was named hassium (Hs). Simultaneously, the name dubnium (Db; from Dubna, the JINR location) was assigned to element   105, and the name hahnium was not used for any element.

The official justification for this naming, alongside that of darmstadtium for element   110, was that it completed a set of geographic names for the location of the GSI; this set had been initiated by 19th-century names europium and germanium. This set would serve as a response to earlier naming of americium, californium, and berkelium for elements discovered in Berkeley. Armbruster commented on this, "this bad tradition was established by Berkeley. We wanted to do it for Europe." Later, when commenting on the naming of element   112, Armbruster said, "I did everything to ensure that we do not continue with German scientists and German towns."

Isotopes
Hassium has no stable or naturally occurring isotopes. Several radioactive isotopes have been synthesized in the laboratory, either by fusing two atoms or by observing the decay of heavier elements. As of 2019, the quantity of all hassium ever produced was on the order of hundreds of atoms. Thirteen isotopes with mass numbers ranging from 263 to 277 (with the exceptions of 274 and 276) have been reported, six of which—hassium-265, -266, -267, -269, -271, and -277—have known metastable states, although that of hassium-277 is unconfirmed. Most of these isotopes decay predominantly through alpha decay; this is the most common for all isotopes for which comprehensive decay characteristics are available, the only exception being hassium-277, which undergoes spontaneous fission. Lighter isotopes were usually synthesized by direct fusion between two lighter nuclei, whereas heavier isotopes were typically observed as decay products of nuclei with larger atomic numbers.

Atomic nuclei have well-established nuclear shells, and the existence of these shells provides nuclei with additional stability. If a nucleus has certain numbers of protons or neutrons, called magic numbers, that complete certain nuclear shells, then the nucleus is even more stable against decay. The highest known magic numbers are 82 for protons and 126 for neutrons. This notion is sometimes expanded to include additional numbers between those magic numbers, which also provide some additional stability and indicate closure of "sub-shells". In contrast to the better-known lighter nuclei, superheavy nuclei are deformed. Until the 1960s, the liquid drop model was the dominant explanation for nuclear structure. It suggested that the fission barrier would disappear for nuclei with about 280   nucleons. It was thus thought that spontaneous fission would occur nearly instantly before nuclei could form a structure that could stabilize them; it appeared that nuclei with Z   ≈    103 were too heavy to exist for a considerable length of time.

The later nuclear shell model suggested that nuclei with about three hundred nucleons would form an island of stability in which nuclei will be more resistant to spontaneous fission and will primarily undergo alpha decay with longer half-lives, and the next doubly magic nucleus (having magic numbers of both protons and neutrons) is expected to lie in the center of the island of stability in the vicinity of Z    =    110–114 and the predicted magic neutron number N    =    184. Subsequent discoveries suggested that the predicted island might be further than originally anticipated; they also showed that nuclei intermediate between the long-lived actinides and the predicted island are deformed, and gain additional stability from shell effects. The addition to the stability against the spontaneous fission should be particularly great against spontaneous fission, although increase in stability against the alpha decay would also be pronounced. The center of the region on a chart of nuclides that would correspond to this stability for deformed nuclei was determined as 270Hs, with 108 expected to be a magic number for protons for deformed nuclei—nuclei that are far from spherical—and 162 a magic number for neutrons for such nuclei. Experiments on lighter superheavy nuclei, as well as those closer to the expected island, have shown greater than previously anticipated stability against spontaneous fission, showing the importance of shell effects on nuclei.

Theoretical models predict a region of instability for some hassium isotopes to lie around A   =    275 and N    =    168–170, which is between the predicted neutron shell closures at N    =    162 for deformed nuclei and N    =    184 for spherical nuclei. Nuclides within this region are predicted to have low fission barrier heights, resulting in short partial half-lives toward spontaneous fission. This prediction is supported by the observed eleven-millisecond half-life of 277Hs and the five-millisecond half-life of the neighbouring isobar 277Mt because the hindrance factors from the odd nucleon were shown to be much lower than otherwise expected. The measured half-lives are even lower than those originally predicted for the even–even 276Hs and 278Ds, which suggests a gap in stability away from the shell closures and perhaps a weakening of the shell closures in this region.

In 1991, Polish physicists Zygmunt Patyk and Adam Sobiczewski predicted that 108 is a proton magic number for deformed nuclei and 162 is a neutron magic number for such nuclei. This means such nuclei are permanently deformed in their ground state but have high, narrow fission barriers to further deformation and hence relatively long life-times toward spontaneous fission. Computational prospects for shell stabilization for 270Hs made it a promising candidate for a deformed doubly magic nucleus. Experimental data is scarce, but the existing data is interpreted by the researchers to support the assignment of N   =    162 as a magic number. In particular, this conclusion was drawn from the decay data of 269Hs, 270Hs, and 271Hs. In 1997, Polish physicist Robert Smolańczuk calculated that the isotope 292Hs may be the most stable superheavy nucleus against alpha decay and spontaneous fission as a consequence of the predicted N   =    184 shell closure.

Natural occurrence

Hassium is not known to occur naturally on Earth; the half-lives of all its known isotopes are short enough that no primordial hassium would have survived to the present day. This does not rule out the possibility of the existence of unknown, longer-lived isotopes or nuclear isomers, some of which could still exist in trace quantities if they are long-lived enough. As early as 1914, German physicist Richard Swinne proposed element   108 as a source of X-rays in the Greenland ice sheet. Although Swinne was unable to verify this observation and thus did not claim discovery, he proposed in 1931 the existence of "regions" of long-lived transuranic elements, including one around Z   =    108.

In 1963, Soviet geologist and physicist Viktor Cherdyntsev, who had previously claimed the existence of primordial curium-247, claimed to have discovered element   108—specifically the 267108 isotope, which supposedly had a half-life of 400 to 500    million years—in natural molybdenite and suggested the provisional name sergenium (symbol Sg);  this name takes its origin from the name for the Silk Road and was explained as "coming from Kazakhstan" for it. His rationale for claiming that sergenium was the heavier homologue to osmium was that minerals supposedly containing sergenium formed volatile oxides when boiled in nitric acid, similarly to osmium.

Cherdyntsev's findings were criticized by Soviet physicist Vladimir Kulakov on the grounds that some of the properties Cherdyntsev claimed sergenium had were inconsistent with the then-current nuclear physics. The chief questions raised by Kulakov were that the claimed alpha decay energy of sergenium was many orders of magnitude lower than expected and the half-life given was eight orders of magnitude shorter than what would be predicted for a nuclide alpha-decaying with the claimed decay energy. At the same time, a corrected half-life in the region of 1016   years would be impossible because it would imply the samples contained about a hundred milligrams of sergenium. In 2003, it was suggested that the observed alpha decay with energy 4.5   MeV could be due to a low-energy and strongly enhanced transition between different hyperdeformed states of a hassium isotope around 271Hs, thus suggesting that the existence of superheavy elements in nature was at least possible, although unlikely.

In 2006, Russian geologist Alexei Ivanov hypothesized that an isomer of 271Hs might have a half-life of around $+1.8 −0.17$ years, which would explain the observation of alpha particles with energies of around 4.4   MeV in some samples of molybdenite and osmiridium. This isomer of 271Hs could be produced from the beta decay of 271Bh and 271Sg, which, being homologous to rhenium and molybdenum respectively, should occur in molybdenite along with rhenium and molybdenum if they occurred in nature. Because hassium is homologous to osmium, it should occur along with osmium in osmiridium if it occurs in nature. The decay chains of 271Bh and 271Sg are hypothetical and the predicted half-life of this hypothetical hassium isomer is not long enough for any sufficient quantity to remain on Earth. It is possible that more 271Hs may be deposited on the Earth as the Solar System travels through the spiral arms of the Milky Way; this would explain excesses of plutonium-239 found on the ocean floors of the Pacific Ocean and the Gulf of Finland. However, minerals enriched with 271Hs are predicted to have excesses of its daughters uranium-235 and lead-207; they would also have different proportions of elements that are formed during spontaneous fission, such as krypton, zirconium, and xenon. The natural occurrence of hassium in minerals such as molybdenite and osmiride is theoretically possible, but very unlikely.

In 2004, JINR started a search for natural hassium in the Modane Underground Laboratory in Modane, Auvergne-Rhône-Alpes, France; this was done underground to avoid interference and false positives from cosmic rays. In 2008–09, an experiment run in the laboratory resulted in detection of several registered events of neutron multiplicity (number of emitted free neutrons after a nucleus hit has been hit by a neutron and fissioned) above three in natural osmium, and in 2012–13, these findings were reaffirmed in another experiment run in the laboratory. These results hinted natural hassium could potentially exist in nature in amounts that allow its detection by the means of analytical chemistry, but this conclusion is based on an explicit assumption that there is a long-lived hassium isotope to which the registered events could be attributed.

Since 292Hs may be particularly stable against alpha decay and spontaneous fission, it was considered as a candidate to exist in nature. This nuclide, however, is predicted to be very unstable toward beta decay and any beta-stable isotopes of hassium such as 286Hs would be too unstable in the other decay channels to be observed in nature. A 2012 search for 292Hs in nature along with its homologue osmium at the Maier-Leibnitz Laboratory in Garching, Bavaria, Germany, was unsuccessful, setting an upper limit to its abundance at $250,000,000$ of hassium per gram of osmium.

Predicted properties
Various calculations suggest hassium should be the heaviest group 8 element so far, consistently with the periodic law. Its properties should generally match those expected for a heavier homologue of osmium; as is the case for all transactinides, a few deviations are expected to arise from relativistic effects.

Very few properties of hassium or its compounds have been measured; this is due to its extremely limited and expensive production and the fact that hassium (and its parents) decays very quickly. A few singular chemistry-related properties have been measured, such as enthalpy of adsorption of hassium tetroxide, but properties of hassium metal remain unknown and only predictions are available.

Relativistic effects

Relativistic effects on hassium should arise due to the high charge of its nuclei, which causes the electrons around the nucleus to move faster—so fast their velocity becomes comparable to the speed of light. There are three main effects: the direct relativistic effect, the indirect relativistic effect, and spin–orbit splitting. (The existing calculations do not account for Breit interactions, but those are negligible, and their omission can only result in an uncertainty of the current calculations of no more than 2%.)

As atomic number increases, so does the electrostatic attraction between an electron and the nucleus. This causes the velocity of the electron to increase, which leads to an increase in its mass. This in turn leads to contraction of the atomic orbitals, most specifically the s and p1/2 orbitals. Their electrons become more closely attached to the atom and harder to pull from the nucleus. This is the direct relativistic effect. It was originally thought to be strong only for the innermost electrons, but was later established to significantly influence valence electrons as well.

Since the s and p1/2 orbitals are closer to the nucleus, they take a bigger portion of the electric charge of the nucleus on themselves ("shield" it). This leaves less charge for attraction of the remaining electrons, whose orbitals therefore expand, making them easier to pull from the nucleus. This is the indirect relativistic effect. As a result of the combination of the direct and indirect relativistic effects, the Hs+ ion, compared to the neutral atom, lacks a 6d electron, rather than a 7s electron. In comparison, Os+ lacks a 6s electron compared to the neutral atom. The ionic radius (in oxidation state +8) of hassium is greater than that of osmium because of the relativistic expansion of the 6p3/2 orbitals, which are the outermost orbitals for an Hs8+ ion (although in practice such highly charged ions would be too polarised in chemical environments to have much reality).

There are several kinds of electronic orbitals, denoted by the letters s, p, d, and f (g orbitals are expected to start being chemically active among elements after element 120). Each of these corresponds to an azimuthal quantum number l: s to 0, p to 1, d to 2, and f to 3. Every electron also corresponds to a spin quantum number s, which may equal either +1/2 or −1/2. Thus, the total angular momentum quantum number j = l + s is equal to j = l ± 1/2 (except for l = 0, for which for both electrons in each orbital j = 0 + 1/2 = 1/2). Spin of an electron relativistically interacts with its orbit, and this interaction leads to a split of a subshell into two with different energies (the one with j = l − 1/2 is lower in energy and thus these electrons more difficult to extract): for instance, of the six 6p electrons, two become 6p1/2 and four become 6p3/2. This is the spin–orbit splitting (sometimes also referred to as subshell splitting or jj coupling). It is most visible with p electrons, which do not play an important role in the chemistry of hassium, but those for d and f electrons are within the same order of magnitude (quantitatively, spin–orbit splitting in expressed in energy units, such as electronvolts).

These relativistic effects are responsible for the expected increase of the ionization energy, decrease of the electron affinity, and increase of stability of the +8 oxidation state compared to osmium; without them, the trends would be reversed. Relativistic effects decrease the atomization energies of the compounds of hassium because the spin–orbit splitting of the d orbital lowers binding energy between electrons and the nucleus and because relativistic effects decrease ionic character in bonding.

Physical and atomic
The previous members of group   8 have relatively high melting points: Fe, 1538    °C; Ru, 2334    °C; Os, 3033    °C. Much like them, hassium is predicted to be a solid at room temperature although its melting point has not been precisely calculated. Hassium should crystallize in the hexagonal close-packed structure (c/a   =    1.59), similarly to its lighter congener osmium. Pure metallic hassium is calculated to have a bulk modulus (resistance to uniform compression) of 450   GPa, comparable with that of diamond, 442    GPa. Hassium is expected to be one of the densest of the 118 known elements, with a predicted density of 27–29 g/cm3 vs. the 22.59 g/cm3 measured for osmium.

The atomic radius of hassium is expected to be around 126   pm. Due to the relativistic stabilization of the 7s orbital and destabilization of the 6d orbital, the Hs+ ion is predicted to have an electron configuration of [Rn]   5f14    6d5    7s2, giving up a 6d electron instead of a 7s electron, which is the opposite of the behaviour of its lighter homologues. The Hs2+ ion is expected to have an electron configuration of [Rn]   5f14    6d5    7s1, analogous to that calculated for the Os2+ ion. In chemical compounds, hassium is calculated to display bonding characteristic for a d-block element, whose bonding will be primarily executed by 6d3/2 and 6d5/2 orbitals; compared to the elements from the previous periods, 7s, 6p1/2, 6p3/2, and 7p1/2 orbitals should be more important.

Chemical
Hassium is the sixth member of the 6d series of transition metals and is expected to be much like the platinum group metals. Some of these properties were confirmed by gas-phase chemistry experiments. The group   8 elements portray a wide variety of oxidation states but ruthenium and osmium readily portray their group oxidation state of +8; this state becomes more stable down the group. This oxidation state is extremely rare: among stable elements, only ruthenium, osmium, and xenon are able to attain it in reasonably stable compounds. Hassium is expected to follow its congeners and have a stable +8 state, but like them it should show lower stable oxidation states such as +6, +4, +3, and +2. Hassium(IV) is expected to be more stable than hassium(VIII) in aqueous solution. Hassium should be a rather noble metal. The standard reduction potential for the Hs4+/Hs couple is expected to be 0.4   V.

The group 8 elements show a distinctive oxide chemistry. All the lighter members have known or hypothetical tetroxides, MO4. Their oxidizing power decreases as one descends the group. FeO4 is not known due to its extraordinarily large electron affinity—the amount of energy released when an electron is added to a neutral atom or molecule to form a negative ion —which results in the formation of the well-known oxyanion ferrate(VI),. Ruthenium tetroxide, RuO4, which is formed by oxidation of ruthenium(VI) in acid, readily undergoes reduction to ruthenate(VI),. Oxidation of ruthenium metal in air forms the dioxide, RuO2. In contrast, osmium burns to form the stable tetroxide, OsO4, which complexes with the hydroxide ion to form an osmium(VIII) -ate complex, [OsO4(OH)2]2−. Therefore, hassium should behave as a heavier homologue of osmium by forming of a stable, very volatile tetroxide HsO4,  which undergoes complexation with hydroxide to form a hassate(VIII), [HsO4(OH)2]2−. Ruthenium tetroxide and osmium tetroxide are both volatile due to their symmetrical tetrahedral molecular geometry and because they are charge-neutral; hassium tetroxide should similarly be a very volatile solid. The trend of the volatilities of the group   8 tetroxides is experimentally known to be RuO4    <    OsO4    >    HsO4, which confirms the calculated results. In particular, the calculated enthalpies of adsorption—the energy required for the adhesion of atoms, molecules, or ions from a gas, liquid, or dissolved solid to a surface—of HsO4, −(45.4   ±    1)    kJ/mol on quartz, agrees very well with the experimental value of −(46    ±    2)    kJ/mol.

Experimental chemistry
The first goal for chemical investigation was the formation of the tetroxide; it was chosen because ruthenium and osmium form volatile tetroxides, being the only transition metals to display a stable compound in the +8 oxidation state. Despite this selection for gas-phase chemical studies being clear from the beginning, chemical characterization of hassium was considered a difficult task for a long time. Although hassium isotopes were first synthesized in 1984, it was not until 1996 that a hassium isotope long-lived enough to allow chemical studies was synthesized. Unfortunately, this hassium isotope, 269Hs, was synthesized indirectly from the decay of 277Cn; not only are indirect synthesis methods not favourable for chemical studies, but the reaction that produced the isotope 277Cn had a low yield—its cross section was only 1   pb —and thus did not provide enough hassium atoms for a chemical investigation. Direct synthesis of 269Hs and 270Hs in the reaction 248Cm(26Mg,xn)274−xHs (x   =    4 or 5) appeared more promising because the cross section for this reaction was somewhat larger at 7    pb. This yield was still around ten times lower than that for the reaction used for the chemical characterization of bohrium. New techniques for irradiation, separation, and detection had to be introduced before hassium could be successfully characterized chemically.

Ruthenium and osmium have very similar chemistry due to the lanthanide contraction but iron shows some differences from them; for example, although ruthenium and osmium form stable tetroxides in which the metal is in the +8 oxidation state, iron does not. In preparation for the chemical characterization of hassium, research focused on ruthenium and osmium rather than iron because hassium was expected to be similar to ruthenium and osmium, as the predicted data on hassium closely matched that of those two.

The first chemistry experiments were performed using gas thermochromatography in 2001, using the synthetic osmium radioisotopes 172Os and 173Os as a reference. During the experiment, seven hassium atoms were synthesized using the reactions 248Cm(26Mg,5n)269Hs and 248Cm(26Mg,4n)270Hs. They were then thermalized and oxidized in a mixture of helium and oxygen gases to form hassium tetroxide molecules.

 * Hs + 2 O2 → HsO4

The measured deposition temperature of hassium tetroxide was higher than that of osmium tetroxide, which indicated the former was the less volatile one, and this placed hassium firmly in group 8. The enthalpy of adsorption for HsO4 measured, $3 grams$, was significantly lower than the predicted value, $−46 kJ/mol$, indicating OsO4 is more volatile than HsO4, contradicting earlier calculations that implied they should have very similar volatilities. For comparison, the value for OsO4 is $−36.7 kJ/mol$. (The calculations that yielded a closer match to the experimental data came after the experiment, in 2008.) It is possible hassium tetroxide interacts differently with silicon nitride than with silicon dioxide, the chemicals used for the detector; further research is required to establish whether there is a difference between such interactions and whether it has influenced the measurements. Such research would include more accurate measurements of the nuclear properties of 269Hs and comparisons with RuO4 in addition to OsO4.

In 2004, scientists reacted hassium tetroxide and sodium hydroxide to form sodium hassate(VIII), a reaction that is well known with osmium. This was the first acid-base reaction with a hassium compound, forming sodium hassate(VIII):

 * + 2 NaOH →

The team from the University of Mainz planned in 2008 to study the electrodeposition of hassium atoms using the new TASCA facility at GSI. Their aim was to use the reaction 226Ra(48Ca,4n)270Hs. Scientists at GSI were hoping to use TASCA to study the synthesis and properties of the hassium(II) compound hassocene, Hs(C5H5)2, using the reaction 226Ra(48Ca,xn). This compound is analogous to the lighter compounds ferrocene, ruthenocene, and osmocene, and is expected to have the two cyclopentadienyl rings in an eclipsed conformation like ruthenocene and osmocene and not in a staggered conformation like ferrocene. Hassocene, which is expected to be a stable and highly volatile compound, was chosen because it has hassium in the low formal oxidation state of +2—although the bonding between the metal and the rings is mostly covalent in metallocenes—rather than the high +8 state that had previously been investigated, and relativistic effects were expected to be stronger in the lower oxidation state. The highly symmetrical structure of hassocene and its low number of atoms make relativistic calculations easier. , there are no experimental reports of hassocene.

title: Hassium