Wednesday, 11 May 2011
Model of Vestas Sailrocket 2 and her (unmounted) wing, copyright Sailrocket and Paul Larson.
by Paul Larson (in Walvis Bay, Namibia)
The wing went up effortlessly and we proceded to head up the course to try and go for a sail.
The big modifications we had made was to spend a lot more time configuring the boat as it is meant to be. Sounds easy and obvious... but there is nothing obvious about this boat. What turned out to be right, at first felt wrong. The good news was that it involved a rather drastic move forward of the beam and wing. This will make getting the boat started a lot easier. We also worked on the system to pull the beam further forward to help her even more in the start up phase. We also increased the range of the rudder and made the wing more upright. The friction in the wing bearings was also reduced to help the wing feather i.e. turn 'off' easier.
As we were towing the boat backwards up the course with the wing fully eased, I was sliding up and down the fuselage checking the fore and aft stay tensions. The whole lot goes a bit loose and wobbly when the wind is blowing from the wrong side. We are very far from being comfortable with it all.
It was as we were turning the nose of VSR2 through the wind that we literally hit a snag. The middle and lower wing sections fouled each other as they passed. The lower section is restrained so now the large middle section was also restrained. The trouble was that the wing was now sheeted on backwards and in this configuration it is not supported by the shrouds. The whole 'shooting match' pitched forward. I motioned for the RIB to yank the nose around which Jeffro duly did. The rig dived forward again. The beam bent and the wing cracked and crunched like a tree about to fall. I was sure it was coming down. There was nothing I could do but watch and wait for the bow to come around.
Schematic diagram of how Vestas Sailrocket 2 should look, copyright Sailrocket and Paul Larson.
Thankfully it did. The shrouds picked up the load and the interference cleared itself. We took it all ashore. The part that did all the cracking and crunching was thakfully only a minor piece of fairing. Damn.... my heart was in my mouth. This feeling was supposed to be locked in a container back in the UK with the first boat.
We identified where the interference was and decided to take the boat home to double check that nothing else had been damaged by the unexpected loads and distortions.
It's now the following day and I'm happy to say that everything seems ok. We dodged a bullet there and will be out saling again this afternoon. We opened the wing right up to hopefully avoid any other foul ups. We already thought the clearance was enough but it turned out that a little bit of mast bend would close the gaps up enough at the back of the wing to allow them to foul. Once they fouled, it would increase the tendency for the mast to bend. The whole wing would lock up.
Beer not Grinder...
We were all very happy to be sitting in 'The Raft' later that night having a beer rather than sitting in the container with a grinder.
It's a new boat and these things will happen. We have three weeks left to start revealing the performance of the boat so are keen to sail at every opportunity. We will try and knock any risky luxuries out of the program that might jeopardise us seeing what we need to see. For now we will just lower the rig between runs until we are totally confident in its ability to feather.
We have a full team here so we are not short of hands. We are not building these boats to sell them... just to prove a point. The focus is on getting up to speed and this shouldn't be compromised... even if it requires a little ugliness along the way.
The sun is finally out and we are about to put the wing back on.
It seems that our drag 'hump' is around 8 knots. I reckon that if we can sail up to 10 knots then we can do 30 knots. Malcolm reckons we will need around 18 knots of wind to do this. It looks like we might get that today.
Fingers crossed and thumbs held.
Vestas Sailrocket 2