When the game is up… The Verdier-designed production Pogo 3s (above) again topped the Series Division in the 2019 Mini Transat, winner Ambrogio Beccaria pulling off a stunning personal performance with only two Proto designs finishing ahead of him. Raison’s first Maxi production scows succumbed to a string of technical issues but were also not as well-prepared as their much practised Pogo competition. In many conditions the slippery Pogos can fight hard, but look at the inset shot of a Maxi Series Mini powered up reaching and lifting over the waves, then compare it to the classic bow-down attitude of the Pogo to see where this story is heading…
the front, but it’s not all about that. Every- thing comes back to the bow slope, which we describe as the spatulate. It generates lift, so the boat does not bury the bow when you push really fast in big winds. Its motion and general behaviour in the sea is quite different from conventional boats, it goes over the waves rather than through them. The pronounced rocker of the hull also makes it easy in difficult conditions, facilitating its ability to pitch up and down without fuss and without the slowing effect of digging into the waves.’ While Lipinski and Hardy took turns at
the helm to get out of the Channel, against the wind and in the face of ‘complicated’ seas, after Ushant the autopilot worked tirelessly. The 415.6nm 24-hour run was carried out entirely under pilot, between the Canaries and Cape Verde, ‘and in not necessarily favourable conditions, because there were cross seas, short and very rough. The only favourable factors were the strength of the wind, and the fact that we were sailing straight on one gybe. ‘We were downwind, 135-140° off the
true wind, under medium spinnaker, stay- sail and with two reefs in the mainsail. We realise that very often with this type of boat we go faster by reducing the sail.’ So rather like the big multihulls. ‘Speed creates apparent wind so we
don’t need a lot of canvas,’ confirms Raison. ‘Besides, scows don’t like to sail over - powered. The front shape above the bilge is not made to go into the water – if you do stick your nose too far into the wave then the brake comes on rather suddenly…’
42 SEAHORSE If at such speeds sailing is not easy on
the human components (Lipinski and Hardy were usually crawling, as on an Imoca, ‘taking care not to hurt ourselves’), the boat itself is usually very dry, and according to David Raison this is typical of scows. ‘Without a forefoot in the water the hull does not create spray, nor a vertical wave rising above the deck edge – the water is diverted away more horizontally. ‘This keeps the scow from being wet all
the time like the other boats, including down below, which means the crew get much less fatigued. The scow sailor also has a better view of the bow of his boat (which is rarely possible on the foiling Imoca, by the way) – and all of these aspects contribute to performance.’ A dry deck is also a direct speed factor.
‘Strictly mechanically, the water that lands on the deck before flowing aft represents a mass that is accelerated, suddenly going from zero speed to 20kt. This energy must be recovered somewhere. Let’s assume that this amount of water corresponds to 1% of the boat’s displacement: it will lose 1% of its speed. At 20kt that is two-tenths of a knot.’ On the other hand, these hulls have their
weak points, especially in light airs: ‘com- pared to a traditional canoe hull they can drag a lot of water in a flat sea’. The Magnum, Raison’s first design, was
also by his own admission ‘complicated to sail downwind in a breeze and in a short sea, with a tendency to engage the bow in a wave’. This situation was improved consid- erably with his second Mini scow, Maxi- mum, which was less extreme, a little
shorter at the waterline and also with better mass concentration. ‘It’s an easier boat, more versatile, more
comfortable sailing VMG downwind,’ says Raison. ‘Remember that 747 and 865 were not designed for the same course: in the 2011 Mini Transat to Brazil it was necessary to be able to make the power of the hull speak for itself, power- reaching between the Doldrums and the finish [David was often sailing n°747 3kt faster than his rivals!]. When the next two editions finished in the West Indies we put more emphasis on sailing downwind.’ Similarly, for the design of his Max 40
Class40, ‘we did not pursue absolute maxi- mum power, to preserve good performance in light winds’. Raison also wanted to extract more upwind potential. ‘In general Class40 boats do not sail very
well upwind, and there is a significant loss of performance through the movement of the keel when the boat pitches in rough seas. We have tried to compensate with a larger keel fin area.’ With a long ballast torpedo extending behind the fin this leads to an L-shaped keel, where the standard in Class40 would be the T-shaped keel, the objective being to move the centre of mass aft without changing the centre of lift. Another standout feature on the first
Raison Class40 is the tapered angular deckhouse running almost to the bow. This solution has several virtues,
according to Raison. ‘The bridge has only flat surfaces, without curves, which simpli- fies construction, reduces mould manufac- turing costs and minimises surplus resin. It
CHRISTOPHE BRESCHI
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