So, yes, what is the easiest way to add some volume to a board? Stick on some think pad foam in the back? This would be for a foil board that can use a bit more volume in the back to, hopefully, reduce its drag in displacement ... 10 liters would make a big difference.

have a look at this thread:
www.seabreeze.com.au/forums/Windsurfing/Foiling/Curing-a-tail-release-problem-fun-and-games-with-epoxy

Paducah said..

powersloshin said..
have a look at this thread:
www.seabreeze.com.au/forums/Windsurfing/Foiling/Curing-a-tail-release-problem-fun-and-games-with-epoxy

Thanks for the shout out. Need to post a pic now that the paint has cleaned things up .

That really didn't add any meaningful volume but, as mentioned in that thread, there is definitely merit to making sure the trailing edges are sharp, release well; and the bottom finish doesn't let water bead up (ie wetsanding to at least 400-600 grit).

Sailed that board today and still super happy with the change in behavior. Even with empty foil tracks and a bottom handle, it just scampers off the water.

duzzi, what board are we talking about and what are it's current dimensions, etc? I'd think it's going to be hard to get 10 l of real displacement without some foam/glass/epoxy cosmetic surgery. That's like three big milk cartons worth of volume. Deck pads are only going to help when the deck/pads are awash.

It is my Flikka foil board. 117L x 77 x 207 ... that would be nice to make a bit more quick to gain speed and get on the foil in low wind/small sail conditions when the tail is under water. Volume is always the hardest thing to judge when buying a board, but it would have been better at 125 or so, with all the extra volume toward the back.

Don't want to glass over the beauty and I was thinking just same thick pads in the back (or the inflatable baloons suggested above) ... but maybe it is useless and i'll learn to use bigger sails for the conditions.

duzzi said..

It is my Flikka foil board. 117L x 77 x 207 ... that would be nice to make a bit more quick to gain speed and get on the foil in low wind/small sail conditions when the tail is under water. Volume is always the hardest thing to judge when buying a board, but it would have been better at 125 or so, with all the extra volume toward the back.

Don't want to glass over the beauty and I was thinking just same thick pads in the back (or the inflatable baloons suggested above) ... but maybe it is useless and i'll learn to use bigger sails for the conditions.

That is, indeed a nice board. I don't think the volume is that far off. More questions, if you don't mind - your weight? your biggest foil wing? what sail size are you putting on? what conditions are you aiming for on the low end? what does the bottom of the board look like?

My offhand impression as an idiot on the internet is and I understand that you may have done every bit of this:
a) target a mid aspect foil wing from 1300-1500 for both lift and not too much drag from a bigger shovel type wing
b) make sure the edges under the back third of the board are crisp, use a glass qcell/microsphere bog and get all the edges nice and crisp. If water beads up on the bottom, wet sand to 600.
c) use a powerful sail for the size ie something freestylish with lots of power and a fairly taut leech.
d) I don't know what the tail cut outs look like but they can be refined or even filled in a bit. Tail cutouts help in getting the board at an angle (too much volume in the rear) and not having too much volume when touching down but it almost sounds like you have the opposite issue. You can do this on your own -having a vacuum bag is helpful but not crucial. Not sure what your comfort level is on taking a router to your beautiful board but I'd think you have someone in your area that does board work if you aren't.

I think, practically, that the first two interventions are the most cost effective in getting you off the water more quickly. If you are under 80 kg, I don't think the board is that far off in getting up in 12-14 kts with a 5 something if everything is optimized.

Paducah said..

duzzi said..

It is my Flikka foil board. 117L x 77 x 207 ... that would be nice to make a bit more quick to gain speed and get on the foil in low wind/small sail conditions when the tail is under water. Volume is always the hardest thing to judge when buying a board, but it would have been better at 125 or so, with all the extra volume toward the back.

Don't want to glass over the beauty and I was thinking just same thick pads in the back (or the inflatable baloons suggested above) ... but maybe it is useless and i'll learn to use bigger sails for the conditions.

That is, indeed a nice board. I don't think the volume is that far off. More questions, if you don't mind - your weight? your biggest foil wing? what sail size are you putting on? what conditions are you aiming for on the low end? what does the bottom of the board look like?

My offhand impression as an idiot on the internet is and I understand that you may have done every bit of this:
a) target a mid aspect foil wing from 1300-1500 for both lift and not too much drag from a bigger shovel type wing
b) make sure the edges under the back third of the board are crisp, use a glass qcell/microsphere bog and get all the edges nice and crisp. If water beads up on the bottom, wet sand to 600.
c) use a powerful sail for the size ie something freestylish with lots of power and a fairly taut leech.
d) I don't know what the tail cut outs look like but they can be refined or even filled in a bit. Tail cutouts help in getting the board at an angle (too much volume in the rear) and not having too much volume when touching down but it almost sounds like you have the opposite issue. You can do this on your own -having a vacuum bag is helpful but not crucial. Not sure what your comfort level is on taking a router to your beautiful board but I'd think you have someone in your area that does board work if you aren't.

I think, practically, that the first two interventions are the most cost effective in getting you off the water more quickly. If you are under 80 kg, I don't think the board is that far off in getting up in 12-14 kts with a 5 something if everything is optimized.

I am 70 Kg and use (sort of) just one foil a Sabfoil 790. Biggest sail I have been using is a 5.4 and I am pushing the lower wind limit. I go out in slogging conditions waiting for a gust because around here a 12-15 average means gusts to 20. That might be it, suggestion c) might be in order, I have a ACX 6.0 or 6.5 that should work better in very light airs. b) is intriguing, the board only has sharp edges just a bit longer than at the small cut outs. d) is probably more that I want to do. It could be a fun project, but the board should be completely fine in 12-15 knots and 4.7-5.4.

Sandman, I am a trim 70 Kg, can't really loose any more weight. But I am asking because I noticed the difference in pick up between my finned Patrik 122 and my Futura 109, kind of day and night, which makes me wonder about a fatter tail Flikka. Maybe I'll just borrow a JP foil 135 from a friend of mine for a while ...

I found that I could not hold big sails, and it was more noticeable trying to go upwind, because the board was not wide enough.
I made a sort of platform that can use only with large sails and it helped.




this is the first version, after I refined it a bit

Well AWS made some really good points, in particular for me about standing forward while pumping up to keep the tail from sinking (if that is the issue, and not the whole board sinking). On my Goya Bolt 135 the tail also sinks in light wind conditions, because it is a relatively narrow tailed slalom board. So in light winds 8-11 knots with a bigger sail I step forward of the front foot strap so my front foot is next to mast base and close to the centerline (but not on it) while I am pumping up until I start to plane on the water, then I slide my feet back and pop the tail with my rear foot to lift off, need to move back very smoothly to stay on the plane, any slightly off balanced movements and you will come off the plane. Depending on the conditions, I will do that either unhooked, or hooked-in. Again, it is fairly tricky, and requires near perfect balance when moving back into the front foot strap while planing, and popping the tail, and once you break free of the water you may need to still pump the sail or the foil 1-2X to get up all the way and then level off, can feel like you are going up over a hump in the air, and then shifting your weight forward when you reach the top of the hump in order to level off the board and foil for the flight.

Of course, for your foil board you may have to make some adjustments to what I described for my slalom board.

I have the center of mast base at 108.5 cm from center of front foil screw, that has worked perfect for me with an AFS W95 Freeride foil, but your foil box is more forward than the foil box on the Bolt, so somewhere between 104 and 108 and you should feel it balance perfectly, remember 1/2-1 cm can make a big difference! And in light winds may still need to give the tail a pop with your foot to get up off the water. The Sabfoil W790 at 1550 cm2 is a big wing for your weight, that means more drag, so will need really good pumping technique in light winds, and being so big it should pump really well, takes less balance to pump up using foil versus sail IMO, but pumping sail will get you up earlier, pumping sail at first and then adding foil as you get moving on the water is very helpful in light winds, but takes a lot of balance and rhythm coordination, just takes practice.

The Sabfoil W790 1550 cm2 has been discontinued and replaced by the W950 at 1350 cm2, even W950 would be big for your weight, but a lot easier to pump up in light winds due to less drag and higher aspect.