Forums > Windsurfing   Gps and Speed talk

What's the concensus on closing the gap?

Reply
Created by NotWal > 9 months ago, 7 Dec 2013
NotWal
QLD, 6633 posts
7 Dec 2013 3:33PM
Thumbs Up

Cribby says forget it. I assume he says that because it only works some of the time and the some of the time you have your sail foot in the water.

When you bear off at speed do you find the foot of your sail over the board or over the water?

kato
VIC, 2287 posts
7 Dec 2013 8:27PM
Thumbs Up

You'll get 50/50 on this For me its about getting the sail into the correct position to deliver its power down the mast into the fin in the conditions that you are currently sailing in. Some in very light winds I will close the gap and keep it closed. Seams to work

RAL INN
VIC, 2557 posts
8 Dec 2013 8:34AM
Thumbs Up

At certain angles to wind it is the way to go but mainly on slalom/race sails.
Obviously any angle that has optimum sheet in position lining up with sail closing gap to board and well powered.

Best reason to close gap it that it feels so sweet when you lock in to that position on a nice long run. When the sail is touching your toes, all the crap trips and winds and frustration get cancelled out and you hoot at the top of your lungs.

Boombuster
QLD, 485 posts
8 Dec 2013 8:41AM
Thumbs Up

Nice flat water close the gap yes in chop its a bit hard with board bouncing all over the place.
Light wind I find the better you can close the gap you lock in the power & it feels good.
Always rig the sail with little downhaul rope showing correct extension helps to achieve this.

jsnfok
WA, 898 posts
8 Dec 2013 2:00PM
Thumbs Up

its hardly the reason you go fast vs EVERYTHING ELSE

Bonominator
VIC, 5477 posts
8 Dec 2013 8:54PM
Thumbs Up

^^ Yeah it's good but not that important. Best to be trimming everything else right and keeping the sail clear of chop and the water in general. If you're fully closing it, probably should put your mast a little further forward.

Simon100
QLD, 478 posts
8 Dec 2013 10:02PM
Thumbs Up

Select to expand quote
Bonominator said..

^^ Yeah it's good but not that important. Best to be trimming everything else right and keeping the sail clear of chop and the water in general. If you're fully closing it, probably should put your mast a little further forward.


why would you move the mast foot forwards if the board is trimmed well just to make the sail sit up a bit more ?

Weather your sail is over the board or the water depends on heaps of things like the angle your going , wind speed, your speed but i find generally locking the sail down balances out the whole set up . People will hate this but i recon heaps of that guy cribs stuff is wrong

petermac33
WA, 4600 posts
9 Dec 2013 4:07AM
Thumbs Up

I tried a 5.1 m code red yesterday for the first time. Had to come in and change the extension four times as the foot of the sail kept trailing in the water! From 15 cm ext all the way up to 20 cm ext and it was still trailing in the water,sometimes anyway. Had to change my technique a little,trying not to fully sheet in. In the gusts it's harder anyway to fully sheet in. The trailing foot was a real pain. Every time it made decent contact with the water I lost the board trim,forcing me further downwind. One thing I hate about race sails is most are cut too low at the foot. Anyway,I agree,sheet in when you can,in big gusts though stay slightly sheeted out with upper body weight twisted to the front of the board to stop the board flying too much.

sailquik
VIC, 4091 posts
9 Dec 2013 11:45AM
Thumbs Up

Select to expand quote
petermac33 said..

I tried a 5.1 m code red yesterday for the first time. Had to come in and change the extension four times as the foot of the sail kept trailing in the water! From 15 cm ext all the way up to 20 cm ext and it was still trailing in the water,sometimes anyway. Had to change my technique a little,trying not to fully sheet in. In the gusts it's harder anyway to fully sheet in. The trailing foot was a real pain. Every time it made decent contact with the water I lost the board trim,forcing me further downwind. One thing I hate about race sails is most are cut too low at the foot. Anyway,I agree,sheet in when you can,in big gusts though stay slightly sheeted out with upper body weight twisted to the front of the board to stop the board flying too much.



Here are a few things you can try to adjust you foot out of the water without extending your base:

Check the mast track position. If you can bring it back further it makes the sail more upright and you can often get the sail foot at just the right angle ie. not dragging in the water. Some boards just don't have the mast track back far enough to suit modern race/slalom sails, especially older boards.

The rake angle of the fin, and/or its position in the box will also affect overall trim. With my 28cm - 40 degree raked weed slalom fin in my IS110, I have to bring the mast track back further to stop the foot dragging. (It also allows the board to ride a bit higher in the nose with is a good thing for me with this particular board to help free its trim up).

The sail trim also affects the angle of the sail. I have found that when I downhaul some sails more, they want to rake back more as the center of effort moves down and forward.

Smaller race sails often are best matched with a smaller slalom or speed board. If you try to use them on a large board you sometimes can't get the mast base back far enough to trim the foot out of the water.

In my experience, Guy Cribs tips are mostly, in general, a good starting point, but there are many specific situations where they can't be always taken as gospel. If it's not working, change it until it feels like it is working. Generally speaking, closing the gap works to stop the flow of air around the bottom of the sail from the high pressure side to the low pressure side. The board forms fence. This is a well known aerodynamic principle and works well in some situations to increase the efficiency of the sail. It really only applies to speed, slalom and freeride sails with a longer, low cut foot, and often works best when on a tight reach or upwind.

Bonominator
VIC, 5477 posts
12 Dec 2013 10:32AM
Thumbs Up

Select to expand quote
Simon100 said..

Bonominator said..

^^ Yeah it's good but not that important. Best to be trimming everything else right and keeping the sail clear of chop and the water in general. If you're fully closing it, probably should put your mast a little further forward.


why would you move the mast foot forwards if the board is trimmed well just to make the sail sit up a bit more ?

Weather your sail is over the board or the water depends on heaps of things like the angle your going , wind speed, your speed but i find generally locking the sail down balances out the whole set up . People will hate this but i recon heaps of that guy cribs stuff is wrong


Ahh yeah I meant back, but only far enough so to not encourage the nose of the board to lift.

petermac33
WA, 4600 posts
13 Dec 2013 7:55AM
Thumbs Up

If you use a stiffer top section than bottom section this should increase the difficulty in closing the gap due to less twist off? Anyway,going to try bottom section of my 400cm blueline mast out with the top section of a 430 Tushingham mast that fits perfectly. Will see.



Subscribe
Reply

Forums > Windsurfing   Gps and Speed talk


"What's the concensus on closing the gap?" started by NotWal