A good day...but what is going on with these foils?
Wed, 30 Nov 11 21:46
Walvis Bay rose to my challenge today and delivered a near perfect speed sailing day for us. This is why we come here.
VESTAS Sailrocket 2 is in the best shape of her life. The whole boat is starting to feel like a finished piece and I am really happy with her.
We did 3 runs today. The first one we did with the conventional foil in. We have added two fences to prevent air from getting sucked down from the surface. One fence is just below the bend (transition) and one is right at the top. It felt like I got ventilation on our last outing when VSR2 went into a big bear away so we added these fences to stop this.
The first run today went well and was very smooth. All the little details were making the whole experience so much enjoyable and as mentioned, it was near perfect conditions. The new launching system meant that I got up close to the beach much sooner than previously and this makes for a much longer run. The leeward pod was flying high but I was easily able to lower it using the flap control on my left.
The run was very enjoyable. Fast and effortless. Just after the timing hut she performed her old trick again and went hard into a bear away. I put in a couple of turns on the wheel to correct it and immediately stopped the run. Hmmmm. It would seem that fences didn't fix that then.
I still managed a top speed near 51 knots and a 500 meter average around 49.38 knots. This would be a new 'B' class world record for craft with our sail area... but I'm not that interested in that. I went faster with a passenger a month or so ago. We are after bigger game here.
Conditions were building so considering we hadn't discovered the magic to make that foil work I decided to do the ol' switcharoo over to the new ventilated 'wedge' foil. The guys had to go back to the container to collect it but in an hour or so we were back up to the top of the course and ready to roll. The start went great but even early on in the run I got this terrible noise and shuddering vibration coming from the main foil. I was only doing about 30 knots but there it was. It sort of felt like what I would assume cavitation would feel like. Not a cool or sophisticated noise... more like an engine throwing a rod! When I turned onto the course it smoothed out and the run went very well again. Once again I enjoyed it and it felt fast. VESTAS Sailrocket 2 is just effortless to sail now and I can savour the speed sensation without fear. She cruises at 50 like a car down a highway.
The, just past the timing hut again, she made that horrible noise which felt like running the tip aground on concrete. The drag pulled me from 50 back down to around 30 and once again I was forced to abandon the run. This was weird. Once again I hit a peak speed around 51 knots. This really is weird. I mean with effectively three different foils i.e. conventional-no fences, conventional-fences, ventilated, we have hit nearly the identical speed in very similar winds. Maybe it's a coincidence involving many factors but either way, there it is.
Conditions were still epic. It was just soooo flat along the shore. Gusting 28 knots and glassy in close. Pure speed sailing porn! We were so close to getting some bigger scalps than the B class record. I want to get the Australian record which is just over 50 knots and the unofficial 'Boat' record off Hydroptere which is around 51.4 knots or 2 knots quicker than my previous run. Either of those would be a nice way to finish the day. I stated the third run but once again I got that terrible draggy shudder. This time it was more persistent and I canned the run at the timing hut. I had only peaked at 30 something knots. What the hell was going on here. We went over the main foil and rudder but it all seemed fine. No obvious signs of cavitation. No damage. Basic boat settings. More Hmmmmmm.
we dropped the rig at sunset.
We have been sitting back here in the container downloading data and digesting as much varied info as we can get. We get a lot from each run. 6 High Def cameras, 1 Cosworth data logger, 3 GPS systems including the mighty TRIMBLE used for record ratification and a TACKTICK wind system with data logger. Multiply that by 3 runs and It's no surprise that we are still here at 10:30 p.m. having just downloaded it let alone digested it.
Funny thing is that I'm pretty happy with today. Breaking this record is like solving a big puzzle and today we got a whole bunch of clues. We did get some great data. The boat itself really impressed me. She is a real noble beast who now feels like she is trying to help us. The boys have done a great job sorting out the details on these windless days gone and I can really notice it. She's slick.
So we will digest all this new info. I already have a few things I want to querie. It appears from the masthead camera that the foil is running very close to the ditch created by the ventilating forward mounted rudder. It should be about a meter away. We have already double checked this whole aspect and remeasured it all to triple check. It seems very odd. Has VSR2 dropped into a mode of sailing that we haven't planned for and that she needs to be shaken out of. VSR1, our first boat, used to drop into a mode where she would drag sideways down the course at about 12-15 degrees. We couldn't believe it as it was still doing 38 knots. It was something you couldn't model or predict and yet there it was. Once we became aware of it and accepted it, we made the mods and began to unleash the potential.
I'm beginning to feel that there is something big we are missing here.
We are very definitely in the lab. We'll get to the bottom of this one. Two weeks to go from tomorrow. Come on Walvis, give us a few more like that.