Update
Silk purse, sow’s ear… oh, but you can. The long, slender, fast and deeply sexy superyacht Yas actually started out life as the Dutch naval frigate Piet Hein, launched in 1978. After a spell with the Greek Navy she was purchased by Hamdan bin Zayed bin Sultan Al Nahyan and shipped (sorry) to Abu Dhabi where, under the eye of naval architect and stylist Jacques Pierrejean, she was transformed into this speedy-looking beastie and relaunched in 2011 – now also lengthened by another 12-metres. Silly not to, while we’re here…
movable fin called the ‘skate wing’ located at the bottom of the daggerboard, the elevator of the central rudder and that of the leeward rudder. This allows us to divide by 10 the wetted surface of the boat! Speed now jumps in huge steps, by 4kt, 8kt, sometimes by 10kt or more in a single acceleration. ‘The foils are acting like the wings of the plane, providing a vertical
force at least equal to the weight of the boat for take-off and con- tributing to the lateral and longitudinal stability while flying. The skate wing manages how high the platform flies above the water. It carries the greatest load. Rudders are used for steering as on any boat but they are equipped with an elevator or adjustable flap, essential to the stability of the boat which serves to raise or dive the boat. Then by adjusting the rake the lift of each appendix can be modified inde- pendently of each other to optimise the configuration in flying mode. ‘On Actual the foils are either fully retracted or fully extended. The
rake is modified by rotating the fin forward and back over a range of approximately 6°. Due to the asymmetry of the profile the foil already provides some lift at 0°. At -2° it is neutral and at +4° it lifts you very strongly. ‘The foil is a piece weighing more than 400kg that moves over
1.50m. It takes five or six minutes to retract or deploy, using the coffee grinder to activate the hydraulic pump that controls all the rams onboard. And there are many!’ Banque Populaire skipper Armel Le Cléac’h adds: ‘If I have
20 minutes to lift a foil I manage my effort very precisely. I have sensors on the column and, like a cyclist, I set the required number of watts. The system then dictates my work rate so I avoid entering the red zone – which is very bad on a long race.’ ‘In addition to the rams used to adjust the appendages, there are
others used for the canting of the mast and to control the luff tension of the headsails,’ says Le Blévec. ‘There are also intermediate settings on the foil shafts, the vertical
part of the foil, which has a double curvature. You go to full extension upwind which puts the tip as horizontal as possible. When reaching you bring in the foil with the effect of turning the L-shape of the foil into a V for greater efficiency. ‘The skate wing serves to release the central hull when you go
fast enough to fly. First the floats are out of the water but not the central hull. Then the skate wing allows it to take off as well. It can carry the entire 14-15-tonne weight of the boat and, because it is
16 SEAHORSE
in the centre, it does not try to twist the platform. ‘The skate wing is adjusted using a “steering” wheel. This makes
the control more readable than operating it blindly from the column of the coffee grinder. It is also more responsive than pumping with a lever to operate a valve to move the foil. ‘Whereas handling the skate foil is time consuming and tiring,
managing the other appendages is easier and faster because the loads are less, they are balancing and trimming –not so much lifting. As an example, one turn on the coffee grinder moves the rudder elevator enough to change the pitch of the central hull by several degrees... which completely changes the behaviour of the boat. So you have to act gently. ‘Apart from the electric ram of the autopilot everything else is
manual on an Ultim. It goes without saying that hydraulics are essen- tial. There are two coffee grinders so you can be four on the handles sailing with a crew. The left column drives the winches and the main hydraulic pump. On a conventional sailboat you spend your time adjusting the sails to go as fast as possible. On an Ultim you spend most of the time adjusting the appendages for the same purpose. ‘If the conditions are stable, it’s cool. If the weather is changing
it can become extremely physical. Upwind we have a minimum speed of 25kt to fly correctly (on Actual this requires 17-18kt of wind) and then you make the best possible heading. The ride is less uncom- fortable than on a conventional boat – like an Imoca [laughing] – because the foils absorb much bouncing into the sea. ‘But as soon as you are at 20kt of wind, even less solo, you must
start to reduce sail. The theory is that as soon as you’re flying you can reduce sail area. Then the switch from one to two reefs arrives quickly on these boats, certainly by 25kt TWS. ‘We have six sails onboard: a mainsail and five headsails. The
J0, or gennaker (350m2), is attached at the bow and hoisted to the top of the mast while the J1 is hoisted roughly to the level of the first reef. The furled sails are hoisted using the winch, then locked off and the luff tension provided by a hydraulic ram attached at the tack point. And finally you have to trim in the sail… which takes a hell of a time and considerable physical effort! ‘Sail changes do not happen as with a crew –when you are racing
solo you must accept you may not have the perfect sail for several hours because the manoeuvre can cost you all that you can gain. For example, to go from J0 to J1 takes a whole hour, during which
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