CNDB Don Shead 45, ALLIAGE – The Story Behind Her Design
November 10th, 2023
We are delighted to be listing the exceptional CNDB Don Shead 45, ALLIAGE. She was built by the Antibes-based yard of Chantier Naval de Biot, using the structurally superior, yet lightweight, alloy Sealium Designed by the legendary Don Shead. ALLIAGE is a completely usable, yet insanely capable powerboat. Resembling a silver bullet, she features trademark Shead sea-keeping (especially at speed), a raked bow profile, and with her lift rails arcing up gracefully to her bow, she is a signature piece.
Don Shead’s History & Career
Don Shead was the brilliant maverick British designer who penned such design classics as the DS45 for Linssen Yachts, the DS110 for Halmatic, and a raft of iconic Sunseeker hulls from the frenetic Superhawk 34 to the mighty 37M. His expertise was gained not only from a studio easel, but also from a racing career starting in his teenage years; when he broke the B-Class outboard powered hydroplane water speed record on Coniston Water in 1958. Having continued racing, he advanced into applied mechanics and electrical engineering, and consulted for luminaries such as Stirling Moss. He then entered the 1961 Daily Express Cowes-Torquay Powerboat Race (alongside Sir Max Aitken) in a borrowed boat (which did not finish…), met Sir Tommy Sopwith in 1962 (who was racing a Wynn/Walters design), and struck up a friendship and racing rivalry that would mould the future of British powerboat racing.
The Development of the ALLIAGE design
In 1963, Shead had Renato Levi design him a hull and structure, which he fitted out to become TRIDENT, in which he won the Production Entry C-T Race of that year; which was won overall by Levi himself in the groundbreaking A’SPERANZIELLA. This crucial experience of driving Levi hulls fast, and adapting others’ designs, led Shead to design his own hull for 1966 – building & winning in LEAN II (a terrible pun on shed…) and resulting in the design for 1967 of AVENGER. Then the orders started coming in after a starring role at the London Boat Show.
Tommy Sopwith asked Shead to increase his design orbit from 25’ to 92’, commissioning the build of the beautiful PHILANTE VI, and so began the Shead domination of larger motor-yacht design. At the same time, aluminium was in its infancy as a boat-building material, but Shead Seized upon its potential, and T2 & MISS ENFIELD led to offshore classics such as HTS, which won the brutal 1972 London – Monte Carlo Race – and thus his pedigree was set in stone.
Thus, ALLIAGE came to be. The classic “Shead line” is a long, lean and hungry hull – working a narrow beam forward and up to a high, buoyant bow, with plenty of lift from aggressive spray rails arcing from the buttock lines upwards into the chines. The design is both characteristically soft upwind, yet forgiving when running downwind and downwater – and does have the trademark Shead looks to the hull.
The Building of CNDB Don Shead 45, ALLIAGE
She was built by Chantiers Naval de Biot, based in Biot, Antibes, using Sealium alloy in 2004. Sealium exhibits:
15% higher welded strength limit than conventional 5083 (AG4) alloy.
Significant (20%) weight-saving properties against 5083 (AG4) alloys.
Improved corrosion and improved resistance to fatigue than conventional alloys.
Same properties of use as conventional 5083 (AG4) alloy.
More recyclable than conventional 5083 (AG4) alloys.
Same formability in terms of cutting, flexing & shaping as per conventional 5083 (AG4) alloy.
25% more expensive in raw form than 5083 (AG4) alloy.
Less malleable than 5083 (AG4) alloy.
We have the table-scanned set of original Don Shead Ltd. plans for her build – and it is fascinating to see the draughtsman’s skills in rendering the sheets of alloy into a devastatingly capable machine.
She is a long-legged, muscular offshore cruiser with high-speed performance, huge build strength, and look simply awesome. With a protected cockpit and race-spec hardware, her taut lines are fully ready to increase the criminally low hours on her twin Seateks, and those beautiful Trimax drives are ready to cleave their way through the briny.
She has been in long-term Ownership and has been thoroughly doted-on. What an opportunity to own a “proper” boat!