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Most of the fun (less than) half of the price
Javier Soto Acebal describes his new 40ft raceboat design as 25-30 per cent IRC, 25-30 per cent ORCi with all the rest being pure Fast40+. Given the sales success of Acebal’s Soto 40 and a base price of US$345,000 for his latest boat, this one will surely give a lot of ambitious owners serious pause for thought...
This project has focused on a predeter- mined balance between the formulas ORC, Fast40+ and IRC. We first studied the varying formats used for local racing here in South America and from that iden- tified the order of priority across the three systems while also ensuring international appeal to a wider audience.
The choice of variables that most influ-
ence performance, accounting for rating effects, varies depending on the system being considered. Displacement, draught, stability, materials and distribution of wetted surface, as well as sailplan, must all reflect the rule at hand.
But these variations can each be quite 56 SEAHORSE
subtle, which today allows us to create a boat that will be a satisfactory all-round performer under the different systems. The brief for this boat was to take account of the balance between these formulas while creating an affordable 40-footer that was both very fast as well as quite simple and easy to sail to her poten- tial. Given current strong competition in the 40ft size range, the last requirement in particular presented a serious challenge. What makes an easy-to-steer raceboat, for example, does not often make for the fastest boat possible.
To have a design with the capacity to make easy mode changes in the future, to suit different venues and different rule systems more specifically (realistically, variations in displacement, trim and stabil- ity), it is essential to have a strong base to start from, thus a structurally strong and lightweight hull with efficient appendages as standard and a high-ballast ratio. The new boat is being built by Javier Mendez at M-Boats in Argentina, using primarily uni-directional and bi-direc- tional E-Glass fibres, consolidated with epoxy resin, vacuum and post-cured in an oven. Uni-directional carbon is employed in those areas that are permitted under ORC without incurring big penalties; carbon capping of the keel floors, plus all of the longitudinals and primary structural frames, is permitted between 30 and 70% aft of the stem and below deck only. Outside this area only E-Glass is used, similar to the Soto 40 one-design. This way we avoid triggering the ORC ‘carbon
hull penalty’ (and maintain better control of the boat’s price).
This construction system results in significant cost savings compared with a higher-tech build, along with the improve- ment in rating. And executed correctly you will still get a boat with excellent stiffness. Engineering is being undertaken by Pure Design & Engineering under the direction of Giovanni Belgrano.
The deck plan features the maximum beam carried aft to the transom, allowing the crew to move to the stern with no loss of righting moment. The topside sections are flared heavily all the way from bow to stern with little variation in angle, thanks to the use of a local chine in the bow area and a complex set of compound curves as you approach the transom.
The design quickly achieves a high- stability form with heel while maintaining a well-balanced underwater shape. This allowed us to use powerful stern sections to ensure a flat wake at most speeds with little or no lateral waterflow aft adding to hull drag. The final result offers the poten- tial of very high-speed sailing with plenty of dynamic stability and good control. The underwater sections start off circular at the bow turning elliptical towards the middle and stern of the boat. The final shape was identified after following an iter- ative process aimed at minimising the ratio of wetted area (variable) versus displace- ment (fixed), without losing sight of pre- serving the correct inertia (stability) with the chosen waterplane. The emphasis was on rapidly gaining dynamic stability with
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