Please select your home edition
Edition
SW newsletters (top)

Longbow - a purpose-built escape capsule made from epoxy composite

by Jake Kavanagh 14 Mar 05:00 PDT
David-John Gibbs, the driver for the Longbow hydroplane attempting the speed record © Wessex Resins

The British team attempting to break the water speed record in a jet-powered hydroplane are well aware of the risks, so the pilot will be able to survive a crash in a purpose-built escape capsule made from epoxy composite, of course.

The Longbow project, with WEST SYSTEM epoxy materials sponsored by Wessex Resins & Adhesives and its associated customer, Robbins Timber, is a purpose-built hydroplane that will be powered by a pair of jet engines. The aim is to hurl this 9-metre wooden hull along in excess of 317 mph (the current record) and reach the finishing line intact. This will snatch the record away from Australia, where it has remained unmatched since 1978.

However, harnessing 6,800lbs of thrust double that of the current record holder Spirit of Australia is not without considerable risk, so the designers are incorporating a special escape capsule into the structure. Should the worst happen, the capsule with its strapped-in driver should be flung clear of the wreckage and remain afloat until help can arrive.

That strapped-in driver will be Royal Navy Pilot Lt David-John Gibbs, who first trained on Sea King helicopters before moving over to fixed wing aircraft. He is also an accomplished powerboat racer so has the experience required to push the hydroplane to its limits.

Construction of the hydroplane began in August of 2018 in a home workshop in Lancashire in the UK. The team, which was also responsible for restoring Donald Campbell's iconic jet hydroplane Bluebird K7, recognised the challenges presented by the shape of Longbow's wooden hull and its specific purpose.

"We had to consider what would happen if an accident were to occur at high speed," says project co-ordinator David Aldred. "The result would be a compromised hull that has possibly lost engine covers or had compartments ripped open, with water flooding in."

The team knew that solutions in other types of high-speed racing craft probably wouldn't work with Longbow, mainly due to her configuration.

"There is a considerable design difference between an Unlimited Circuit Racing hydroplane and an Outright Water Speed Record jet hydroplane," David explains. "The former carries a relatively small turboprop gas turbine in a very wide hull, one specifically built to go around corners as fast as possible. This lends itself to an integral cockpit design as the hull's large internal volume provides enough reserve buoyancy to keep the craft afloat for some time after a breach."

However, the problem gets trickier with the hull shape needed for straight-line record attempts. The much heavier engines need a relatively narrow hull intended to keep any lift to a minimum so the hydroplane doesn't become airborne at speed.

"As such, a damaged jet hydroplane may well have insufficient buoyancy to keep it afloat after a serious crash," David says. "An integral cockpit could possibly take the driver with it to the bottom of the lake. Even with breathing apparatus on board, going down deep in a damaged boat could still prove fatal."

Several ideas were put forward during the design stage and whilst most had merit, there was also the challenge of cost and practicality.

"Some asked: 'Why not just have an ejector seat?' We did approach British ejection seat manufacturer Martin Baker for an option. They explained that whilst a seat ejected from ground level was quite feasible there was no guarantee that it would travel vertically. If the seat shot off at an angle towards the shore the company felt that the potential liability to a third party would be unacceptable, so they respectfully declined to help with the project."

The team turned their attention back to the two remaining options. The first was to create an integral cockpit in a hull designed to stay afloat as long as possible. The second was the 'drag boat' option, where the hull self-destructs during a crash so as to release the capsule on an escape trajectory. By making the capsule from composite, it will prove resistant to damage and continue to float if breached.

"The amount of reserve buoyancy within that capsule will allow it to remain on the surface even when fully flooded," David remarks. "In this respect a timber hull with a separating composite capsule fulfils all our design requirements, so that is the route we will be taking."

The capsule is being designed by freelance advanced composites engineer Paul Martin, who has worked for McLaren and both the Bloodhound and Aussie Invader. We'll bring you the details of how WEST SYSTEM epoxy is being used to make the capsule tough and durable when the build begins.

In the meantime, you can follow the progress of the rest of the project at: www.jet-hydroplane.uk

See more stories and tips at epoxycraft.com/category/blog

Related Articles

Wessex Resins and Adhesives announces line-up
Guest speakers for Southampton International Boat Show Wessex Resins and Adhesives has announced the line-up of guest speakers for its 'in conversation with' day at Southampton International Boat Show 2019. Posted on 4 Sep
Building an 18th century Gajeta part 8
Finishing touches made to old design built with modern epoxy In our latest instalment of the building of a replica of an 18th century Croatian Gajeta, ‘Lipa Moja' becomes the sum of her parts. Many hours of craftsmanship have resulted in a beautiful vessel that is ready to race. Posted on 27 Aug
How to burst bubbles in epoxy
Simple tricks, and what to watch out for If you're finding that you've got bubbles when pouring clear casting epoxy here are some simple techniques to help resolve the problem. Posted on 21 Aug
Fire Retardant Additive for Epoxy Resin
Does what it says on the tin WEST SYSTEM 421 Fire Retardant Additive does what it says on the tin - it retards fire. It is a heavy, non-combustible powder that is added to a fresh mix of epoxy. Posted on 1 Aug
Building an 18th century Gajeta part 7
Modern epoxy techniques on a classic design After several months of intense boatbuilding, the craftsmen at the Betina Shipyard in Croatia are in the final stages of the completing their experimental 7-metre traditional sailing gajeta. Posted on 29 Jul
Happy Birthday to Gougeon Brothers, Inc
Creators of West System epoxy celebrate 50 years Wessex Resins & Adhesives manufacture WEST SYSTEM®, PRO-SET® and ENTROPY RESINS® under licence from the Gougeon Brothers Inc, USA. Below Grace Ombry traces the company's heritage, from its modest beginnings as a boat shop... Posted on 5 Jul
Tips from the Epoxy Professionals
Preparing teak strips for bonding Here's a tip for preparing a teak plank for a small-scale project such as a cockpit table. It could work just as well on a complete deck. Mark at Aquamarine Ltd uses it whenever he wants to bond teak to a substrate (no screws). Posted on 2 Jun
Making a Mouse Boat with Oarsome Chance
Disadvantaged boat-building students use just one sheet of plywood Wessex Resins and Adhesives is a proud sponsor of the charity Oarsome Chance, where disadvantaged and school-excluded young adults learn how to build and repair boats and use them on the water. Instructor Nick Hart describes the making of a 'Mouse Boat'. Posted on 31 May
Raising the bar with Entropy Resins
A sailing club bar top with a nautical theme James Case has been a member of Wells Sailing Club since he was a child. "It's always had the same bar," he says, "but when the club decided to do a major refit, we decided to make a new bar with a nautical theme." Posted on 28 May
Bio-based epoxy resin now available in Europe
Manufacturers of West System epoxy now sell Entropy Resins too Wessex Resins & Adhesives is delighted to announce the launch of a new online store to facilitate ordering the unique range of bio-based epoxy: ENTROPY RESINS. The EU online store has been added to the current North American website. Posted on 19 May
MBW newsletters (top)