Paul Larsen plans to break the outright world speed sailing record this year aboard the 30ft carbon fibre flier Sailrocket

Paul Larsen, the 32 year-old Australian who sailed with Pete Goss aboard Team Philips, plans to break the outright world speed sailing record this year aboard the 30ft carbon fibre flier Sailrocket. Reaching a speed of 50 knots over the 500m course (in 19.5 seconds) is going to be a tough nut to crack but Larsen believes his Sailrocket Team has the ‘right tools for the job’.

This wacky-looking speed machine, which weighs just 140kg (similar to a Hobie 16) and costs a total of £200,000 to design and build, is according to Larsen, more of a proa than a catamaran with two tiny planning surfaces set on a fuselage. And the most unusual thing about this new design is the fact that it flies the leeward hull. The 22sq m rig is positioned on a pod to leeward, with the shrouds always set to windward but, as Larsen points out, unlike most proas, such as Yellow Pages Endeavour, which are effectively one-tack boats, Sailrocket will have a moveable rig.

“What we (the team and Malcolm Barnsley, the designer) have decided to do with the boat,” says Larsen, “is make it a two-tack boat, but you can’t just tack it round, it will involve taking it to the beach and changing the rig around, which will take a couple of hours. The advantage of this is it gives more flexibility as far as speed course venues are concerned and to be able to swap the rig from a starboard setting to a port tack setting, which will allow us to make ourselves available to twice as many speed sites. I think this will be a key point.”

Sailrocket employs an unusual concept, which was first documented by yacht designer and Bernard Smith in the 1960s in which the sail and keel elements are positioned so there is virtually no overturning moment and no net vertical lift.

“Most boats are ultimately limited by their heeling moment – a direct effect of keel and sail opposing each other,” explains Larsen, “but the Sailrocket has been designed so the forces are running directly in line with each other, continuing through to the foil.” To achieve this perfect balance with the rig upright, the hull and the rig pod are set extremely wide apart – a staggering 27ft – using a beam which is effectively like an aeroplane wing holding 40 per cent of the overall weight of the craft when she is going full tilt.

Once this perfect balance has been achieved, the leeward hull then starts to lift, creating ‘ground effect’ where the boat is effectively hovering on a cushion of air. “The rig is totally self-regulating and as soon as the gust hits, it’s got nothing to do but accelerate, just like a controlled kite,” adds Larsen. “It’s capable of 6-36 knots in a blink. At 6-8 knots the apparent wind comes round and it just gets faster and faster. Once the craft is up to speed, there should be no input from the helmsman; everything should be dead neutral and light. Because we don’t have that heeling moment, we don’t have to adjust the sails; we just pull them in and sail in a straight line.

“The main hull will have hydrofoils which will allow us to sail in slightly rougher water. The helmsman will sit/lie, similar to a Formula One car, in a pod at the aft of the main hull with the joystick between the knees and a coarse and fine tune for the mainsheet. The helmsman will steer with one hand on the joystick and the other hand ready to release the coarse tune if anything goes wrong!”

The large, transom-hung rudder will be kicked up once the boat reaches a certain speed and steerage will then be via the small skeg. However, Larsen is keen to point out the possibility of using an air rudder (a foil above the water) which is a similar concept to an aeroplane foil.

Although building of Sailrocket is progressing rapidly at the Jubilee shed at Woolston, Southampton, the design team is at the stage where they need to decide on the concept of the rig. The idea is to have a 22 sq M soft sail (the same as a full Hobie 16 rig or a Tornado mainsail) which can be sheeted in bar tight in 55 knots of wind with no gust response. The alternative is a wing rig.

Whatever the team decide, there is no doubt each new idea will be thoroughly evaluated between now and launch time in an effort to achieve their ultimate goal, which is to beat the 46.52-knot record currently held by Yellow Pages Endeavour.