Sailrocket’S Xxx Xxxxx Speed Record 70
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30 xxxxx record xxx speed strap sailrocket’s YACHTING WORLD YACHTING w how we smashed T smashed we how hen Paul Larsen’s outlandish machine machine outlandish Larsen’s Paul hen FEBRUARY 2013 FEBRUARY their heads. heads. their m atthew atthew s heahan finds out how the project started with with started project the how out finds heahan Vestas Sailrocket 2 Sailrocket Vestas smashed the world sailing sailing world the smashed models and studies in hydrodynamics and ended up with a pencil and a hacksaw a and pencil a with up ended and hydrodynamics in studies and models speed record it was the biggest step forward ever recorded and left experts scratching experts left and recorded ever forward step biggest the was it record speed HE GL Speed in knots 40 60 30 50 20 70 10 0 1972 Crossbow Tim Colman GBR 26.30 ASS 1973 Crossbow Tim Colman GBR 29.30 SpeedRecord Sailing World The 1975 Crossbow Tim Colman GBR 31.10 1975 Crossbow II Tim Colman GBR 31.80 1977 500m records Crossbow II Tim Colman GBR 33.80 1977 Crossbow II Tim Colman GBR 34.40 1980 Crossbow II Tim Colman GBR 36.00 C 1986 Windsurfer Pascal Maka FRA 38.86 1988 Windsurfer Erik Beale GBR 40.48 1990 e Windsurfer Pascal Maka FRA 42.91 1991 Windsurfer Thierry Bielak FRA 43.08 1991 ILING Windsurfer Thierry Bielak FRA 44.66 Year 1993 Windsurfer Thierry Bielak FRA 45.34 1993 Yellow Pages Simon McKeon AUS 46.52 YACHTING WORLD YACHTING 2004 Windsurfer Finian Maynard BVI 46.82 2005 Windsurfer Finian Maynard BVI 48.70 2008 Windsurfer Antoine Albeau FRA 49.09 2008 Kiteboard Robert Douglas USA 49.84 2008 Kiteboard Sebastien Cattelan FRA 50.26 2008 february Kiteboard Alexandre Caizergues FRA 50.57 2009 5 45L’Hydroptère Alain Thébault FRA 51.36 2010 Kiteboard Alexandre Caizergues FRA 54.10 2010 2013 6 Kiteboard Sebastien Cattelan FRA kno55.49 TS . 2010 Kiteboard Robert Douglas USA 55.65 31 2012 Vestas Sailrocket 2 Paul Larsen GBR 65.45 cSAILROCKETruising in’s speed record Wanderer t is impossible to overstate the achievement of Paul Larsen’s Vestas Sailrocket team. The speed essentially a big windsurfer game has now changed, the impossible proved possible, leaving some of the world’s A The hull, which looks rather like the Main foil section – While the foil is conventional Rear float supports aft end of hull and is set at 20° to the hull so that it is in F top hydrodynamics experts wondering how fuselage of an aircraft, is angled at 20° to in its basic function, developing the right line with the direction of travel. The float also accommodates a large to rewrite the textbooks. the direction of travel to take account of characteristics at speed has been the key to retractable skeg, which is used to get Sailrocket under way. Once she has The fastest sailing boat in the word clocked the apparent wind angle and ensure that Sailrocket’s phenomenal success. The design of the reached 20 knots the skeg is lifted up, the drag is reduced and the an average of 65.45 knots over the 500m it is always aligned with it to reduce drag. foil went against the views of many well-established lateral loads taken by the main foil and forward-mounted rudder hydrodynamicists . and proved them wrong. course in Walvis Bay, Namibia, to set a stag- Because Sailrocket is sailed on a reach she’s like an aircraft coming into land in a The wedge-shaped foil section (grey) has a flat Leeward float– this supports gering new speed record. It was not only the biggest leap crosswind. Instead of crabbing across trailing edge. The blue represents the void created by Sailrocket when at rest and at slow in performance that the outright sailing speed record the runway on the approach, which drags ventilating the foil Rear float speeds. As Larsen has become had ever seen, but the greatest ever step forward in any the fuselage sideways trough the air, Main foil more confident in stronger breezes, class of inshore speed sailing boat. she’s been built skewed into the wind the float, wing extension and beam ISailing’s sound barrier has been broken, again. A de- have started off the run underwater cade ago it was the so-called 50-knot barrier that held B Ignore the rest of the boat for a as the sail pressure to leeward back many budding campaigns. Strange things start to moment, turn the page anticlockwise pushes the rig and beam down. through 90° and imagine that this is Main foil – produces forward drive as well as vertical happen to foils at such Wing sail But once under way the a commercial airliner’s wing with a lift, as many other surface-piercing hydrofoils do. speeds, making the ne of the fundamental keys to Sailrocket’s E configuration starts to fly winglet at its outer end The ride height is self-levelling as more speed Direction round number more than performance is eliminating the heeling of travel O creates more lift, which raises the boat. This force, but she’s not the first to do this by a long way. just a convenient man- C The wing develops forward thrust as reduces the amount of foil in the water and By canting their rigs to windward and with the sails made stumbling point. does the wing extension (winglet) on the limits the lift. As the boat slows, it tends to Wing above their heads, windsurfers do it all the time to extension The few that eventual- outboard end as we see it in this view lower, placing more foil in the water and balance out the forces. Once in equilibrium, as they B ly made it through dis- increasing the lift. hammer along in a straight line, there is no heeling D Wing provides the main forward covered that the climb moment on the board itself. Instead, it’s all about thrust and can be altered in its angle from 50 knots upwards balancing the sail forces against the skeg. depending on conditions, just like the sail A FROM ABOVe C was exponential as the In practice, Sailrocket is rather more complex Forward Leeward on a windsurfer. thrust float Forward behaviour of their foils because of her size, but essentially she is just a big Pull the tip of the mast to windward thrust windsurfer with the hull and crew pulling down on continued to be erratic and the wing provides more vertical lift the tip of the mast and a strut lower down instead and difficult to predict. and less forward drive. Tilt the sail more As well as controlling the lift and hence windward heel, the wing of sitting in a harness attached to the wishbone. From 2008 the steps up upright and the opposite happens: more extension also makes the main wing more efficient in the same way as True wind the leaderboard were Sailrocket Darvelid/Vestas H photos: All side force and less vertical force an aircraft’s winglet. The extension blocks the passage of high direction generally small. Above: Larsen ended up in pressure to the low-pressure side around the normal wing tip and in ‘Boom! Glass all over hospital after one crash that the E Main beam – this is an aerofoil doing so reduces the vortex generated here, which in turn reduces Forward float is set at the floor,’ wrote Larsen in team did not want to publicise FACTS AND FIGURES section and provides vertical lift as the drag. Broadly speaking, it makes the wing think it is longer than it is boat speed and hence airspeed a 20° angle to the hull in his blog on 13 November order to align it with the after a first record run. ‘61+ knot peak speed and 54 some- LOA 12.2m 40ft 0in increases. In early designs the beam was Apparent intended to provide all the lift, but this direction of travel. wind Beam 12.2m 40ft 0in direction thing knot average. That outright record is toast. The 2 2 Underneath is the F Total wing area 22m 237ft proved problematic. The wing extension To allow the wing to achieve boat is on fire . the glass ceiling has been smashed.’ Projected wing area 18m2 194ft2 solves the problem rudder, which rotates Forward maximum forward thrust, the And that was just the beginning as Sailrocket put on Crew 1 or 2 on a stock that passes float wing extension helps to lift the the afterburners to annihilate the former record set by Apparent wind speed 73 knots on record run through the float F All floats have stepped hulls to Wing sail Lift main beam (E) and leeward Alain Thébault’s L’Hydroptère in 2009. But even Larsen Construction: pre-preg carbon and Nomex honeycomb reduce drag at speed. Both fore and aft Direction of travel float out of the water. This core. All metalwork titanium. When dismantled VSR2 is couldn’t predict just how far he and his team would foils provide the fore and aft balance for extension works just like a small designed to fit into a single 40ft shipping container. the main hull. The forward float supports punch into new territory in the days that followed. D aeroplane’s wing as it has a flap Main foil supported by Ekspan and built by Composite One of the biggest changes from VSR1 was to put the helmsman and crew While the team’s many supporters around the world the rudder stock, which extends through to increase lift at low speeds, Craft, Cowes.