Aluminium and steel are the primary materials in Quicksilver's construction. The craft is very strong and rigid, yet it is also lightweight for its size, engine power and speed potential. Designing and building a structure that is very strong and rigid is easy. But designing one that is very strong and rigid and light is not. It should go without saying that if a boat is lightweight in relation to its power, it will accelerate faster and in a shorter distance, decelerate faster and in a shorter distance, and generally out-perform, a heavier-weight craft of the same power output. –
The desire to keep weight down is therefore very easy to appreciate. But what about stiffness and strength? Why are they so important too?
Quicksilver's hull structure – because it will move very fast – will be subjected to complex and immensely powerful dynamic forces. Those forces increase as the square of the speed. So the stresses and strains at 200mph are four times greater than they are at 100 mph. And at 400mph, these loadings become 16 times greater. In other words, the magnitude of the forces rises exponentially. A structure that is not strong enough would simply break. And a structure that is not rigid enough, as it flexes excessively under the forces imposed upon it, would cause the angles of the boat's points of contact with the water to alter erratically as it speeds along the lake, compromising its handling and stability.
Because Quicksilver is designed to travel faster than any machine has ever travelled on water before, it must have a hull design and construction like no other. Very strong, very rigid, yet very lightweight for both its size and the forces it must withstand.
Yet in the midst of all this, we wish to employ materials that already have a proven track record in speed-record use – this, for reasons of safety and affordability. So carbonfibre, for example, is not being used in structurally critical areas of the boat. But we have embraced newer technologies in areas where we feel it offers sufficient performance gains, conducive with maintaining the very high safety margins we demand. A good example of this is the widespread use of structural bonding techniques on Quicksilver.
The central section of the hull serves as the structural backbone of the boat. It comprises of a spaceframe, fabricated from high-tensile steel tubing, bearing internal and external aluminium structures which, acting in concert, increase overall strength and rigidity, bestow watertightness, and contribute to the hydrodynamic and aerodynamic characteristics of the craft.
In the image above, a large sheet of aluminium alloy has been laser-cut by a computer-controlled machine to create individual parts from which one of Quicksilver's major structural components was fabricated. Most of the craft's external skin is aluminium alloy, as is a large proportion of its underlying structure. Methods of construction vary throughout the boat, according to the specific structural requirements in different places.
For example, the entire stern section of Quicksilver is a unitary (monocoque) structure made of aluminium, and extensive use is made of bonding techniques rather than welding. Contrast this with the central section of the boat – with welding employed exclusively in the steel spaceframe, and aluminium cladding bonded on. In further contrast, the front section of the boat, known as the bow module, is constructed principally from non-metallic materials using techniques akin to those employed in conventional powerboat and leisure-craft building.
Several companies have collaborated with the Quicksilver team to build the hull ...
The high-tensile steel tubing for the hull spaceframe, which has a tensile breaking-strain of 55 tons per square inch, was manufactured specifically for Quicksilver by tubemaking specialist Accles & Pollock, using material supplied by British Steel/Corus.
White-hot steel roaring across rollers to a Corus of hissing steam, a foundry gives birth to the fastest boat on Earth and Industry rises to the challenge of doing what Britain does best!
The foundry, at Wednesfield, Wolverhampton was where the initial manufacturing process for Quicksilver's hull spaceframe took place. It was the production of a "tube hollow" – the partially-formed expression in steel of a shape that would subsequently be drawn out into long, straight lengths of two-inch-square tubing. This basic tube material was then transported the short distance south to tubemaker Accles & Pollock's factory at Oldbury for completion and emerged as 33 lengths of BSI T59, each 20 feet long. Paul Rollason led the technical input by Accles & Pollock.
The two dramatic images above are not stock shots retrieved from a photo library: they are actual photographs taken in the very first moments that Quicksilver began to take physical form.
Thank you Corus/Tata Steel.
Quicksilver's hull spaceframe design has been the work of two highly experienced engineers: Glynne Bowsher was responsible for the bulk of the design, which enabled the initial manufacturing stage, then Roland Snell subsequently added to this.
Special welding techniques were developed for us by BOC/Linde to fabricate the hull spaceframe, and were independently tested and certified by The Welding Institute in Cambridge. Welding, by the TIG method, was undertaken by a team of three of BOC's top developmental specialists: Steve Moynihan, Chris Birch and Craig Rollinson. Some years earlier, Steve – seen in the centre of the picture above, when Quicksilver started to take shape – had participated in welding work on the spaceframe chassis of Richard Noble's ThrustSSC supersonic car, which the RAF's Squadron Leader Andy Green drove to set the current World Land Speed Record of 763.035 mph.
When welding of Quicksilver's hull spaceframe was completed, BOC's team undertook non-destructive testing (NDT), using the dye-penetration method. This ensured that there were no flaws – hairline cracks, for example – in any of the welds.
For BOC's far-sighted decision to participate in the Quicksilver project, we are deeply indebted to Dr. Duncan Yates, the late Dr. Wendy Peters, and business development manager Shaun Schofield.
The mountings which hold the Rolls-Royce Spey engine in Quicksilver's hull were made for us by Radshape Sheet Metal, of Aston, Birmingham. These are a combination of all-new fabricated structures, all-new machined components, some adapted Buccaneer aircraft engine-mounting parts, and some standard Buccaneer engine-mounting parts. The two side (trunnion) engine mountings are manufactured in steel, while the rear (upper centreline) engine mounting, also in steel, is incorporated within a large hoop structure fabricated in high-performance 7020-T6 aluminium alloy.
Detailed design of a second hoop structure – which also has the ability to partially support the engine, if required – was duly undertaken, and its manufacture by Radshape in 6082-T6 aluminium alloy has been recently completed. This hoop, situated forward of the other one, is known as the trunnion hoop.
As well as their role in the engine-mounting scheme, both hoops make an important contribution to the overall strength and rigidity of the central portion of the main hull structure.
Credit for the design of the hoops/engine mountings goes to several engineering specialists, including Roland Snell and Tim Harrison. We also gratefully acknowledge the contribution of Glynne Bowsher, who kindly undertook the initial conceptual work on this area of the boat's design.
Detailed design of the craft's bow module and keel module is being undertaken by Coupland Bell Ltd., in an arrangement which sees the company's founder, Mark Evans, working as an integral member of the Quicksilver team to bring this part of the project to fruition. Coupland Bell, based in Coventry, has considerable experience in marine-structures design and manufacture. Composite materials are envisaged for the bow and keel, and both modules will be constructed by the Quicksilver team itself.
The shape of the craft's three hulls, of which the bow and keel modules constitute a key part, was developed by the internationally renowned marine architect Lorne Campbell. Working from his design studio in Poole, Dorset, Lorne has contributed vital expertise to the Quicksilver project over a considerable period of time, for which we have, throughout, been most grateful.