Moths - heeled to windwards?

[davidej]

I have just been looking at one of Dylan's clips and I noticed that the moths, unlike any other sailing vessel, seem to invariably to be heeled to windwards.

Made me realise that windsurfers do the same.

Is it just a matter of keeping balance or is there some subtle aerodynamic advantage.

I have never sailed a moth or a board so can someone experienced explain please.

 

[rwoofer]

Leaning to windward means the lift foil is also lifting you to windward, hence goes upwind better. I'm sure others can better that answer....

Windsurfers are different and generally don't need the windward heel other than for balance. If you look at speed sailors their rigs are quite vertical in reality.

 

[Adjag]

There is an advantage (if you have the courage) as the wind creates lift when it hits the sail angled to winward which helps the "boat" lift (or the windsurfer plane). On a heeling yacht the opposite happens, the wind pushes down on the inclined sail increasing the displacement & hence the drag.

 

[davidej]

I can understand the point about generating lift.

Still, it's a very clever trick but I can't work out how the various forces stay in balance

 

[Iain C]

I've got one, so I can confirm that they do indeed go better upwind with some windward heel. You have very little vertical foil in the water when flying so it does stop the boat making leeway. That said, it's bloody hard work, as you are effectively hiking with your feet at head level.

The technique was pioneered by the guy who came up with the modern version of the foiling Moth, Rohan Veal. It was initially dubbed "Veal Heel" but is just the standard way of sailing them now.

With regards to forces etc, conventional sailing logic just goes out the window in a foiling moth. For example, if it's marginal foiling and you see a lull, easing the kicker or mainsheet reduces mast foot pressure and might keep the boat on the foils. If you watch the guys foil gybing, they are on the "old" leeward side of the boat, sat under the boom, for what seems like an age before actually flicking the boom over. The foils actually add a lot of stability...it all looks precarious but in effect you have a chuffing great stabiliser in the water...something a low rider moth never had.