Vestas boy's at it again....

The VESTAS Sailrocket 2 project will be returning to the waters of Walvis Bay, Namibia this September with a new hydrofoil package which they hope will bring them an Outright world speed sailing record.

The record currently stands at 55.65 knots (64 mph) and is held by American Kite Surfer Rob Douglas. VESTAS Sailrocket 2 was built in the VESTAS R+D facilities on the Isle of Wight and launched in the Medina River in March 2011. The project then relocated to Namibia where ideal conditions occur on a regular basis.

From its launch in the UK, VESTAS Sailrocket 2 rapidly progressed up the speed sailing ladder and after only 23 runs, hit speeds over 50 knots down the magical mile long course at Walvis Bay's 'Speed-spot'. The team then made continual improvements to the boat and tried a number of underwater foil configurations but seemed to be hitting a 'glass ceiling' in performance in the low 50 knot speed range regardless of which foil options they tried or how much wind they sailed in.

VESTAS Sailrocket 2 is indeed a radical craft. It looks perhaps more like a plane than a boat because a lot of attention has been focused on the aerodynamic efficiency and stability of the craft however, she still relies very much on the hydrodynamics to allow her to carve across the wind. It is based on a concept where all the overturning forces typically associated with sailing craft are removed. This allows the boat to use the wind created by its own speed to generate a lot of its ultimate power without actually getting overpowered. Whilst VSR2 might actually be sailing in only 25 knots of real wind, at full speed the lightweight, carbon fibre boat and its rigid wing sail feels like it is sailing in over 60 knots of wind and yet doesn't require traditional systems of weights and levers to remain stable.

THE CAVITATION BARRIER

Once you start going through the water over 50 knots you are going to start encountering a phenomenon called cavitation. This can be likened to the hydrodynamic equivalent of the 'Sound Barrier'. The property of the water changes as it turns from liquid to vapour on certain parts of the foil. This requires a very different approach to how you design them. The problem gets even more complicated as air from the surface also tries to get sucked down onto the foil and cause it to lose grip. This mixture of air, vapour and very high-speed water is all very dynamic and extremely hard to model by computer or even in high-speed flow tanks. Most projects to date have simply pushed conventional foil theory to the limits and that's why speed sailing is stuck at the current speeds in the low 50's. VESTAS Sailrocket 2 was designed from the outset to be a breakthrough boat. It is designed to be an ideal testing platform for trialling new foil concepts which will allow us to break through this 'glass ceiling' and perform at speeds well over 60 knots.

http://youtu.be/JBH0J1MyELk