The ancestor of the IMOCAs
In September 1968, Éric Tabarly learned in a nautical magazine about the creation of a new ocean race: a solo Pacific crossing between San Francisco and Tokyo organized by the Slocum Society. But this race is exclusively reserved for monohulls between 22 and 35 feet (10.67 m), exit Pen Duick III and Pen Duick IV. Tabarly therefore decided to build a new boat, which would meet the race programme and be comfortable downwind, the pace best suited to the course.
To design Pen Duick IV, the skipper worked with architects Michel Bigoin and Daniel Duvergie. It is to this duo that we owe the Aikido series boat, a 10 m sailboat that had seduced Tabarly by its program, with a beautiful width and a longitudinal bilge at the buoyancy reducing the wet surface downwind while increasing buoyancy from the first angles of heel.
The aluminium boat was built at Chantiers La Perrière in Lorient, like Pen Duick III and IV and was launched on 4 January 1969.
In order to have a maximum waterline length, the bilge hull's slings are reduced, the width is large (3.50 m), its stern lines are wide and load-bearing and its hull has a step, as on motor boats. To ensure stability, Pen Duick V has a 2.30 m long, deep keel with a 400 kg lead torpedo, equipped with a trimmer on the trailing edge to combat drift. Finally, to reinforce stability without weighing down the boat too much and to compensate for the heel according to the speed, Tabarly has devised a ballast system designed to receive liquid ballast. It only takes 20 minutes with a hand pump to fill the 500 litres of sea water.
It was inspired by the Sand Baggers - very veiled American sailboats that compensate for the list with sandbags placed in the wind - that he came up with this idea, which would be found years later on the monohulls of the BOC and Vendée Globe round the world races.
For the sail plan, it will be a sloop but innovative rig. The skipper will be able to pass - alone - from a sail plan of 63 m2 upwind to 150 m2 downwind thanks to a specially developed system. Twin jibs of 65 m2 are placed on roller struts and are held at the clew point by 7.50 m telescopic poles.
