Wednesday 10 September 2008

Big Moth performance gains are obvious.

One area where there must be a huge drag and potential performance gain is the vortex under the sail. I have not done the maths but ... we twist the sails and so the grunt comes from low down in strong winds. Sails are nice elliptical profiles on the way up but the bottom is definitely not. We use loads of downhaul to flatten and feather the top like a windsurfer, but that does not help the bottom which is doing all the work. So there must be a huge vortex under the sail and around the boom that is pure drag. Our smart windsurfing friends who have similar sails rake the rig back to close this gap.

So we have a 3.3 meter long boat and 2m wide sail so there should be room to cross the boat International Canoe style with the sail on the deck but we need a radical configuration change. Maybe we can do a tramp that goes between the sail and boom from wing bar to wing bar but then how do you tack....?

Also it is a bloody stupid idea to have the centre of lift in the centre of the boat. Why hike so hard when we could double the effective width of the boat. Once we are up we only need a small foil to stay up and why not put that down to leeward as there is plenty of power in the rig?

So while the corporations are working away on the next generation of Moths that will be faster (and bloody good luck to them), I thought it was time to try to see if it was possible to see if an open community discussion could work to get the boats to the next level. Moth performance has always been boosted by bloody obvious ideas like:
- Why not make the boats lighter by using materials with better structural properties.
- Why not make the boat wider with simple hiking racks.
- Why not make hulls lighter and less drag by making them narrower.
- Why not fly above the water on hydrofoils.

So why not move the centre of lift to leeward and reduce the vortex drag under the sail? The only problem is how and how?

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