KEEL, DRAUGHT AND DISPLACEMENT
In all my research on the subject of ideal draught and keel type, there was a consensus that a fixed keel may be better suited for ocean passages, whereas shallow draught, whether with a shorter keel and bulb or a centreboard arrangement, was preferable when cruising. My two last boats had a centreboard and I can state unequivocally that both from the safety and convenience point of view, a centreboard works perfectly, both when exploring shallow areas and on passage.
Many cruising catamarans perform poorly when sailing to windward, although the use of daggerboards, as well as other design features, has seen significant improvements in this respect. It is an essential feature to consider for anyone looking for a performance cruising catamaran.
Displacement should be a serious consideration for those interested in sailing performance, as I know too well from personal experience. At nine tons for her 36ft, my first Aventura was on the heavy side and an indifferent sailer in light winds.
My intention for Aventura II was to have a boat of reasonable displacement, but while the designer followed my suggestion, the builder had other ideas and she ended up with a displacement of 17 tonnes rather than the 12.5 tonnes envisaged by the architect, Bill Dixon. So in light winds she was a source of continuous frustration.
I was determined to get a boat with a lighter displacement for my third Aventura. Indeed Aventura III’S designed displacement of 9.5 tons for a beamy 43-footer was as close to perfect as possible and I always made sure to keep her weight down to a reasonable level.
Aventura IV’S designed displacement was 14 tonnes and even when fully loaded with provisions behaved very well on every point of sailing.
For a long voyage one should make sure that the mainsail is made as strong as possible, with double, ideally triple Uv-resistant zigzag-stitching and protection patches in the areas where the sail may touch the spreaders when fully let out. The furling foresail(s) should be provided with anti-uv strips.
I have considered the subject of the type of mainsail on a cruising boat and have no doubt that a fully battened mainsail, with slab reefing, is still the best answer for those who are interested in performance. Mainsail furling systems have evolved, and some of the boom furling arrangements combine the best of two worlds, by offering a quick and easy way to reduce sail surface, and, as the furling mainsail is provided with battens, the loss of performance is quite minimal.