by Paul Larsen
Vestas SailRocket at speed
The Vestas SailRocket project is returning to the amazing Walvis Bay speed-strip to recommence its sailing program. The goal remains the same, to set the outright world speed sailing record.
Arriving in Namibia on the 14th of August, the team hope to be back sailing within ten days. They plan to be in Namibia for around three months with a view to going for their first WSSRC ratified record attempt during this period.
Paul Larsen (pilot/project leader) - 'The seasonal winds are already beginning to blow across that amazing mile of remote beach and we want to be down there to make the most of it. No other speed sailing project in the world has ever had such regular access to world record breaking conditions. It is up to us to develop both our craft and ourselves up to the potential that Walvis Bay offers.
We have spent over 10 of the last 15 months on location down there and it has been a real rollercoaster. Whilst we have had our share of ups and downs, we have also been steadily improving. Speeds well over 40 knots are now a common occurrence. Whilst our top speed to date is ‘only’ 44 knots, we know where the extra speed lies and believe we know how to get there. It all comes down to control. We believe that we have overcome many of the big issues and now it will be down to the fine detail.
In our last four month session in Namibia we ticked a lot of boxes. We managed to complete 29 runs and reliably demonstrate systems which will figure in the push for higher speeds i.e. flying the leeward pod clear of the water, transition to high speed steering and improved wing control.
We sailed in stronger conditions as required to reach top end speeds and posted much higher 500 meter averages. A small structural failure on our 50th run in Walvis Bay caused an escalation which lead to a significant wipe-out. Vestas SailRocket went from 35 knots on a broad reach to fully tacked and stopped in four seconds!
We now accept that these incidents come with the territory. Despite a broken main beam and damaged wing, we repaired Vestas SailRocket . . . and came out fighting in an improved boat two weeks later. On our 53rd run we posted the best wind-to-boat speed ratio yet. (see video link of all the action attached below)
During our time back here in the UK we have been working with PI Researsh to add another vital element to our data logging system. We will now have load sensors and strain gauges on the rear skeg to record the actual loads it encounters during a complete run cycle.
Combined with the B+G sensors which record the high speed trim-tab-steering angle, the new sensors should tell us exactly how the boat is balanced and how best to configure it for speed. Previously we just relied on measuring the rudder angle but have decided that this is not accurate enough as we enter an arena where funny things can begin to happen underwater. Fractions of a degree can make a big difference where we are going. We want to approach this stage methodically with as much ‘illumination’ as possible.
We, along with the team at Aerotrope, are also looking at configuring the current wing so that there is a slight negative flap angle...or ‘reflex’. This should make the wing more aerodynamically stable. The overall power will be reduced . . . but so will some of the overall drag. If the wing is more stable and we can make it feather safely at a slightly positive angle then it should make life a lot safer and simpler on the course. It will change the way we start and finish the runs and if things go wrong it should prevent the situation from escalating into a full-on wipe-out as has happened before.
It will also mean that we can reduce the amount of strings both externally and internally. This would make the boat lighter, more aerodynamic and reduce the cockpit workload immensely. If we can still get the necessary performance to achieve top end speeds then another box will have been ticked. This is yet to be seen. We don’t want to just keep raising our wind range to make up for spiralling inefficiencies elsewhere as this has its own problems.
If it doesn’t give us enough power to achieve 50 knots, it may still have provided a safer environment to test other aspects in as we move higher up the speed sailing ladder. We can then go back to the more powerful/complex setup.
Once we have trialled the new systems and configured Vestas SailRocket accordingly, we will make definite plans regarding a record attempt.
Nothing improves the breed like competition. We feel that it is time to put our project in the arena against the clock. It will serve to focus our efforts and priorities with a view to setting a world record. The exact timing of this will be determined by the success of the initial trials.'
Video of high speed action... http://www.youtube.com/watch?v=2XOdXPCaQBE (HQ option offered)
Vestas SailRocket website - www.vestassailrocket.com