We hooked on a long tow line and proceeded to slowly pull VESTAS Sailrocket 2 away from the land. Once out I straddled the hull, made my way back to the main foil and lowered her down to the locked position. She definitely looks deeper than the last foil and depth paranoia struck instantly... so up she came again. It’s a bit of a ‘lash-up’ affair right now but pretty soon we hope to be able to do it all from the cockpit. We must protect the foils from the numerous shallows that inhabit the sailing area. VSR2 doesn’t track very well without the foil down and the rudder is next to useless at low speed so I’m pretty much at the mercy of the tow-line and there is no point sitting in the cockpit.

It was a lovely evening. What a joy to be towing this new weapon across the lagoon towards the African sun as it made its way to the horizon at the far end of speed-spot. A beautiful setting for the introduction.

We dropped Hiskia and Ben off on the magical mile that is ‘speed-spot’ as we needed to lighten the Rib for towing. Once away from the shore I lowered the main foil once more and we began towing. The nose float immediately went under. I know not to get alarmed by these things in these programs... not until you fully understand what is happening. This was surprising however as these floats have huge amounts of volume i.e. each one should be capable of supporting the whole boat. The water was flowing very smoothly over the top as the nose is very well rounded for aerodynamic reasons as much as anything. I had a small passenger in the back seat. Mari was carrying the boats new little mascot so she could tell me if she thought it was going to be ‘lucky’ or not. I called the Rib back and Mari jumped in there just to lighten the load a little.

HMMMM!!! COME UP WHEN YOU'RE READY.

 

We were towing VSR2 by the nose and after another short trial we set up a more realistic bridle system. The fact is that the main fuselage needs to travel along at a 20 degree angle. It does not sit fore and aft but is cocked sideways so that it points into the ‘apparent’ wind at high speed and greatly reduces the aerodynamic drag on the boat. I figured that by towing the boat by the nose that we couldn’t get the boat to track straight through the water as the rudder wasn’t effective enough to get things in line at low speed. With the V’d floats being pulled sideways we weren’t getting full hydrodynamic lift, a lot of extra drag and the inclined rear foil was actually getting pushed down instead of up. Basically we were towing a mess through the water. Anyway, no harm... check... tick the box and move on. This will still probably be how we will tow the boat back up the course between runs so still relevant.

We set an approximate bridle so the towing point was about 10-12 feet inboard and set off again. The nose still went down. I found it hard to get an idea on what direction the boat was tracking in. It is very important to how the boat rides as, being a sailing boat... and a foiling sailing boat at that, it is designed to have the load applied from the side for the foil to have a positive angle of attack and be effective. If we weren’t getting that angle right then the foil would be doing either nothing... or worse, working in reverse(Being, inclined and curved in a way to counteract a huge side and up load from the wing, it actually gets a bit more complicated and hard to truly work in a simple towing situation without the up force from the wing). Annoyingly, the nose was still going down and even with the 60 hp engine at full noise, we couldn’t get the boat to ‘pop’ up out of the water. I worked the rudder through its range to see how much response I could get. I had to make sure that it wasn’t fully stalled and off to one side. If it was then it was completely ineffective and just creating drag which added to the whole problem. Quite often the nose would turn more to the right when I turned the steering more to the left. This would be due to the flow becoming re-attached and although the angle was decreasing, the effectiveness would increase. This is all kind of basic stuff but then this rudder shape is not your normal deal, it is a wedge shaped high speed section with a profile more like an axe head than a teardrop. It was still effective at low speed, but only in a very narrow range. Once I got a feel for this and we began a turn to the left, the bow popped up, the drag decreased, the Rib was able to accelerate... and we were off. We punched a big hole through the mythical ten knot barrier and up to the lofty heights of around 16;)

THAT'S MORE LIKE IT. TOW LINE STILL INDICATES WE ARE PULLING AT SLIGHT NEGATIVE ANGLE.

 

With no wing on the boat, the leeward float was riding very high. We were sitting on top of the water and it felt great. The steering became more responsive although, once again, if I went too far it would stall, become ineffective and the drag would slow the whole process.

So as the sun got lower, we played with this whole process a few more times before calling it a day. It was a very interesting little trial and as expected, we learnt a great deal. We will definitely do more towing trials in the days to come and we will start getting a bit more scientific about it all.

It was great to bring VESTAS Sailrocket back to the slipway all wet, pull her up the ramp and then hose her down.

She’s a water creature now. It brought back a distant memory of letting the ducklings go onto the dams for the first time where we grew up. You could feel their joy as a massive piece of their instinctive jigsaw fell into place, “Ahhh, that’s what I am”! Well VSR2, there is still one big piece to add, your wing. That might even go on today.

The whole day made me realise that we are now at the start of a very long leg of the whole journey. The new boat has very little about it that is intuitive, even to someone who has sailed a lot in her predecessor. It will take a lot of patience, practice and understanding to make it all work. Of course there will be issues but I know that these will not be insurmountable. The reward is there waiting for us at the end and problems that seem big on the day will quickly diminish in the big picture. The process of overcoming these obstacles is a big part of the whole challenge so it must be part of our own personal perception of ‘fun’ I guess. I must remind myself of that from time to time.

So party people, here we are. We are now properly back in action. Let the fun begin.

Cheers, Paul.