Interesting ...
I just watched the videos again on the Byte Class site and Ian gives some insight on the Laser dagger board in heavy air.
check it out in video #8
Does anybody else raise the board when beating to windward in a breeze?
Yes, when sailing with standard rig as am a little on the light side. I trade off a little sideways slippage against keeping the boat i) Upright and ii) Flat
Raising the daggerboard for upwind sailing is not a good idea, it will make it harder to keep the boat flat and you'll slip sideways losing distance. Think about the boat being flat, the deeper the blade the more force is required for the blade to displace the water. If you sail with a heel, the blade has less "grip" because of this principle. Even if you are planning upwind its still not a good idea.
Your best bet is to use enough vang so that the blocks don't rise (or rise much) when you ease the sheet, use the cunningham, and ease the main when you're overpowered. You'll sail much faster using the vang and easing the sheet, if its really windy you can be eased more than you'd think, remember you can't get height without speed.
lastly, when you become overpowered you need to hike as hard as you can
Huh ? Your first paragraph is wrong and confused. Raising the board makes it easier to keep flat by reducing lateral resistance.
Essentially when the blade is all the way down and the boat is flat, it requires a greater force to displace the water to either side then when it is up because there is more water surrounding the blade when it is at its deepest point.
... if the boat is flat there is more water that has to be dissplaced in order for the boat to heel to leeward while sailing to windward.
I think 505's have a special centerboard that allows the skipper to change the angle of attack of the foil in the centerboard case. This would help pointing in different wind conditions depending on how fast the water is moving over the foil.
I don't know I was trying to think about it in a different way, you're right about it taking less of a moment to right the boat with a raised daggerboard, and that would probably be a good idea in survival conditions where you're at a complete loss of control, my theory is that when the boat is flat and the daggerboard is all the way down, the daggerboard must displace more water for the boat to heel either way, making it harder to right but providing more stability and more lift assuming you can keep the boat flat. Essentially when the blade is all the way down and the boat is flat, it requires a greater force to displace the water to either side then when it is up because there is more water surrounding the blade when it is at its deepest point.
Imagine the boat fixed at the bow and stern dead center allowing the boat to rotate side to side, the daggerboard will act like a paddle. if the boat is heeled it will be harder to right the boat with the board down because of this, if the boat is flat there is more water that has to be dissplaced in order for the boat to heel to leeward while sailing to windward.
Maybe I'm wrong, but the top guys always say to keep the board all the way down on the windward leg
Thanks Strangler ... I love the 505
I do think it is relevant to the Laser! we are trying to understand how to use the centerboard and looking at other boats and how they work in comparison is a good way to learn.
I'm not convinced any other boats board issues are relevant to the Laser, because the Laser is a slow una sailed boat with a dagger board.
---snip---
I have never heard that someone has found a radically new way of using different amounts of board for different conditions upwind. As far as I know, they spend ages getting a perfect finish on the board, and making sure the brake is brand new to try and stop it slopping around, and then sail with the board right down.
Maybe they do raise the board when it is really windy, but I have never read that.
so which is faster upwind in overpowering conditions?
1. easing the sheet to keep the boat flat with lots of vang and the board down
or
2. raising the board a few inches making it easier to keep the boat flat