Excerpt from “Hydrofoils for everyone” by Claude Tisserand
Claude Tisseran start his experiments in 1965, in 1966 he launch the Véliplane I
It was a trimaran 4.50 m long, 4 m wide, weighing about 125 kg. It was made entirely of plywood. Even the mast was made “to measure”. It was a beautiful piece of 7 m high, designed to receive a sail of 17 m² and which was never mounted, because I had to settle for a sail of 12 m² recovered on my old “As Côte d’Azur” . The first tests of this machine were immediately encouraging: the takeoff was easily obtained with a wind of about 3 force. The speed reached was never really measured, for lack of a speedometer. However, it was much higher than that of dinghies sailing in the vicinity and was to be around 12 to 15 knots. A serious defect first appeared: the machine, provided with a large fixed plane in front of the rudder, practically refused to turn, except by jibe of course! So I started immediately a new empennage, fully mobile (the idea was good) but rather unfortunately formed an interweaving horizontal, vertical and oblique planes whose hydrodynamic result should not be very bright, because it stacked a lot. But this time, the boat was turning, without too much trouble! This is how the summer of 1966 passed. The lack of wind, unfortunately, did not allow me to go out very often. Moreover, the considerable size of the machine, which was perched on its double fixed fins, all wings spread, made it difficult and dangerous job (it is also nowadays the main disadvantage of almost all sailboats with hydrofoils!).
The Véliplane II
The tests of Véliplane I did not exceed a few months, the professional necessities having decided otherwise. This followed a new period of testing of models, which culminated in 1971 in a gear adapted on a hull of “470” ordinary purchased second hand; it is the Véliplane II, which tried to remedy the difficulties of use of the Véliplane I, not folding. Insufficiently stable and fragile, this machine was quickly abandoned.
It is therefore by keeping this old “470” hull that the Véliplane III was made, by simply adding a 4.5 m wide plywood transverse beam carrying the hydrofoils at the end. This formula, constantly improved from 1972 to 1976, is the subject of this project.
It was in this period that Claude Tisseran learned, through the work of J. Grogono – DJNigg and Alexander “Hydrofoil Sailing”, research carried out in England and the USA I discovered also and above all self-compensation and the advantages of the wings High angle: that, really, Claud Tisseran had not thought about it and it is the cause of many setbacks. The Véliplane II was thus strongly modified to take into account at the same time the results of the experiments and the lessons of his Anglo-Saxon colleagues. These modifications resulted in Véliplane III.
The Véliplane III
In order to lose the minimum of time (and money!), Claude Tisseran decided in 1972 to keep the hull and the marine wings of the Véliplane II, but by adding a large transverse beam in plywood which carried the width of the whole to 4,50m. The sea wings were fixed at the end of this beam and their dihedral was raised to 40 °. The folding of the wings was done horizontally, which allowed the grounding without difficulty. This folding is ensured by the sliding inward of the upper end of the vertical against-card serving as the 3rd point of support to the wing (the other 2 points of support being fittings fixed at the end of beam) . This mechanism is operated by 2 cables that allow the raising and lowering of the wings.
The rudder was, according to the ideas of P. Hansford, constituted by a simple small wing placed at the end of rudder (inverted T), which placed it in very good hydrodynamic conditions (no “ventilation” possible). It was in this form that the Veliplane III made its first tests in 1973. The first successful takeoffs took a long time due to various ruptures that occurred at the wing attachments. However, by the end of the summer of 1973, the boat was very easy to take off by force breeze 3 (about 15 knots of wind). The take-off speed was of the order of 10 to 12 knots and peaks of 15 to 16 knots.
Véliplane III was 7th (out of 20 entries) at the 1975 Speed World Championship in Weymouth with 3 runs at 15.9 knots.
This performance, which was 3.5 knots lower than that of Mayfly, though less “evolved” in some respects, amply demonstrated the No.1 defeat of the Véliplane III: its excessive weight (156 kg in total without cox, compared with only 100 kg for Mayfly). This excess weight is also confirmed by a takeoff speed of about 12 knots, against 10 knots for Mayfly. This excessive weight was essentially the old hull of 470, which alone weighed more than 100 kg, despite the removal of all its unnecessary artifices including drifting well.