At 70ft with a beam of 29ft, a dry weight of just 15 tonnes is confirmation that the Goetz-built Saphira is a sophisticated answer to a complex but far from unusual set of owner requirements. Seen bow-on the rigs look tall in terms of overall beam but total sail area is the same as for the client’s previous 55ft catamaran from the same designer. A tremendous amount of research and full-scale testing have gone into making this boat as safe as possible for long-distance sailing taking advantage of the ability to stream sails downwind. Even so such an easily driven platform will rarely need both sails at full hoist
needs to be rotated to windward. If they are left rotated to leeward they will invert in the middle third and fall off in the top third making the sails unreadable. Active rotation to windward allows the battens to pop through quickly forming the correct foil and the mast to assume a normal smooth curve with some leeward fall-off in the top third, depending on wind strength. Sailing upwind is straightforward with
normal trimming of both sails after the rigs are rotated into the wind. Stream the leech telltales and try to keep flow attached just aft of the mast gives great sailing. Bearing off requires attention as both
weight and strength advantage that the owner could not ignore. A straightforward laminate of unidirectional carbon for the hulls and decks and a blend of twill and unis for the structure, coupled with heat pre-formed foam cores and Nomex for the large flat panels, have created a strong and light platform. There are not many cruising boats with
a length of 70ft and a beam of 29ft with a displacement of just 34,000lb. The interior fit-out is cheery and light, built of cored red birch-veneered panels with only enough solid wood to provide strong, handsome accents, fiddles and corners.
Rig(s) Two tall, unstayed, rotating semi-wings with a chord at the boom of about 1m are the basis for a powerful sail plan. With no headsails, the mainsails are proportioned to provide area that is equal to a sloop rig including a full symmetrical spinnaker. So upwind in medium air the default is to sail with reefed mains. Unreefing unleashes the full power of a large, powerful sail plan. Rotating the masts is a sail shape and
sailing efficiency issue. Mast to boom rota- tion is accomplished with hydraulic rams, while mast and boom to boat rotation is accomplished by easing the mainsheets. These masts rotate up to 180° to each
side in normal use, so the systems were designed with take-up reels to accommo- date all the wires, hydraulics and control lines needed to operate the boat and keep the string under control. The boat sails comfortably up to 60° by the lee on either side, so to ensure that
nothing breaks when over-rotating the rigs they are actually designed to rotate through 270° either way or 540° in total. It was a head-scratcher for most sailors. Safety is paramount especially while
cruising. Capsizing a cat at sea is a serious problem, especially with two large rigs. During the planning stages there were several philosophical debates about safety. Should the rigs be strong enough to with- stand a full capsize without breaking or should they break to prevent capsize? Should the sheets and vangs have inline fuses or relief settings? Is there a way to sense load and relieve it before damage or capsize occurs? In the end it was decided to build strong
rigs and include sensing devices for the sheets and vangs which ‘blow’ the controls but without losing control of the sails. Similar safety devices are used by French big multihull sailors and increasingly on their foiling monohulls. One unique aspect of this rig is that
releasing the sheets will automatically free the sails to ‘flag’ downwind. The sailor doesn’t have to make the decision whether to head up or head off in an emergency; the boat can maintain its course while the sails feather.
Underway This is a powerful sailboat for which the biplane rig offers many advantages. It also presents new sailing challenges while learning to handle the boat. Rig rotation is a necessity to keep the
masts in column and the sails properly trimmed. After tacking the front of the rigs
sails must be eased to maintain a zero or small heel angle. With so much power available, heading down too quickly or with no attention to the sheets can cause an unsettling increase in heeling that, if not careful, can cause tripping over the lee- ward bow, which is a problem with any highly powered catamaran. Heading down also poses another
conundrum. There is a point, which is quickly reached, at which the windward sail blankets the leeward sail. This is the dead zone, where speed suddenly and dramati- cally falls off. Easing the weather sail and reattaching flow to the leeward sail before trimming back on returns speed. Generally the windward sail is eased more than the leeward sail under most conditions. And then we are running… wing-in-
wing, but not wing-and-wing the way most sailors think of it. This boat sails with the booms out 135° on either side when the sails become lifting surfaces again rather than just drag sails. Commands get confused. ‘Head up’ is
baffling, but ‘come to port’ or ‘come to starboard’ bring clarity. With the biplane rig the boat is routinely sailed 30 to 60° by the lee with the leeward sail trimmed and the ‘windward’ mast well over-rotated as the weather sail is eased. When sailing up to 80° on either side of
dead downwind, gybing is as simple as turning the boat and trimming the sails slightly. You don’t have to actually gybe the windward main until you plan a transi- tion to a reaching sailing angle. Having learnt to sail the biplane rig on
the test boat, the owners were well versed in the specific handling requirements for the full-sized vessel. But to unpractised crew there is a significant learning curve to climb.
SEAHORSE 57
BILLY BLACK
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