Last time out I noticed a tiny crack on the side of my Severne Fox that droplets of water were coming out of, about mid point of board mid point of rail. Not sure how long it had been there. Taped over it for the session. When I got home, I used a dremel tool to grind off the surface of the board there, just a small opening maybe 1inches by 1/2 inches, foam exposed and laid the board on its side. Water dripped out for about 24 hours, hard to tell how much, maybe 1-2 cups total. No more dripping from the crack.

The board is usually stored vertically, so worried that water had gone toward tail of board. I then drilled 2 holes into top surface board near the tail, maybe about 2 inches from the tail. Put board vertically in my garage. The next morning (now) maybe 14 hours later I have noticed that water dripped out of these holes, very slow, can't tell how much. Maybe more than a few tablespoons.

Any advice on how to proceed? I've pretty much decided not to sail the board for the rest of the season. Any moves to dry the board out further? Drill more holes? Easy to plug holes eventually. For the ground out crack, it's not very deep at all, does it need more than Marine-Tex? If so, I have some fiberglass cloth, I assume that will work for such a small area.

That stinks, but your approach of letting it sit as long as possible sounds correct. If you have multiple openings (crack, holes, drain plug) you could store the board vertically, and create some kind of suction at the low point. If you have vac bag equipment that would work, could do a shop vac intermittently with a slightly loose seal, or even thent the bottom with plastic and put something low pressure and slow like an aquarium air pump inside the tent. If you don't want to actively vent the core you could just stuff some cotton or poly string into the holes to act as a wick to speed drying.

For the crack I'd imagine that dremeling the edges of the hole to create a nice taper, followed by a couple layers of 4 oz cloth would be good as new. Hardest part looks like sanding that curve without making a low sport. Marine tex is nice stuff for filling a ding but thickened or not it doesn't have much structure so tends to fail and crack around the edges.

If you need epoxy or glass supplies let me knwo happy to cut some small bits.

1-2 cups of water is significant. There's probably double that still in there. You should weigh the board and compare that to what the mfg says it should weigh, then you'll know how much water you took on.
The ONLY way to get all the water out is to vacuum bag the board and bake it (put it in the sun). This will cause the water to boil off and you can usually get 98% of the water out. They you repair the damage. The other choice is to repair it and live with a slightly heavier board.

A vacuum and heat are the two main ways to dry out a board. The boardlady suggests 110F as a temperature for drying out a board. See boardlady.com/waterextraction.htm. I've found that if I open the windows in my car a bit on a warm Midwestern day it gets to a good temperature for water extraction. If you go that route, be sure to do some testing regarding the right about of ventilation since getting too hot can cause problems.

If there are multiple holes, I've also tried blowing air through the boards to help dry them out. An aquarium pump works fairly well.

Have been drying out the board and think I have a plan that substitutes vacuum technology with patience. The board has an automatic pressure valve, can't do anything with that. What I have been doing is putting the board in the sun for a few hours, and wicking the 2 bottom holes with cotton sheet remnants. For 3 consecutive days water wicks out the holes, not very much, but then stops after a few hours. I am theorizing that the expansion of the board forces the water out until fully expanded, then stops.
I am thinking that if I subject the board to numerous expansion-contraction cycles with the board propped up, water and then moisture laden air will continue to drain out the board. Summer sun will work fine, but during winter in my basement I could heat the board up every day with an electric blanket for 2 hours, then off.

This is why I suggested you weigh the board. You might be able to get about 80% of the water out with this method. The problem is that the water molecules are drawn into the spaces between the beads. In order to overcome these weak molecular forces (probably van der Waals forces) you need to get the water to boil off. The only way to do that without damaging the board is to lower the boiling point of the water with a vacuum, which also pulls the water vapor out of the boards core.
If you weigh the board accurately without straps and fin in it, you'll know how much water you took on. If you don't mind it being a little bit on the heavy side, then just continue with what you're doing. My guess is that the original amount of water that got in was about 4 lb worth.

David, your comment on the vacuum pump got me thinking about other ways to do it, and if you wanted an easier and lower cost way to apply some suction to the foam core, you can flip an aquarium air pump into a vacuum pump pretty easily: www.instructables.com/Vacuum-Pump-from-Aquarium-Air-Pump/

I would make sure your airline hose doesn't crush under vacuum, but this would be pretty easy to do. You could make a "tent" around the bottom hole with plastic wrap and butyl tape to make a seal, then let vacuum hurry gravity along.

This wouldn't generate anything like the 25hg you use for real composite vauum bagging, but it would probably help for dragging water out over a week or so. I would just make sure your pump doesn't overheat.
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David, unless you have a nicely heated basement, I'd bring the board up on the upper floors of your home where the air is dryer and the heat constant at a nice 70 degrees! Maybe you could keep the board vertical on its tail in a small room where you could bring the temps even a bit higher to "bake" it nicely?!
Sucking the water out by vacuum-bagging the board sounds like the best idea so far though. I don't think it would take long to get most of it out - maybe a few hours?

The whole point of using a vacuum bag is to lower the boiling point of the water in the board, convert it to vapor, and THEN it can be sucked out of the board. Without raising the temperature above 100 F (assuming 1 PSIA) vacuum, the water will NOT come out; it will stay in the liquid phase and be more strongly attracted to the styrofoam beads. The most cost effective way to achieve this, is to wait until you have a hot day in the summer and then put it out in the sun, or even better, if you have an uninsulated and accessible attic space, put it in there. My attic gets 140-150 F on a really hot day with full sun. Then you don't have to contrive all manner of contraptions to heat the board while it's under vacuum. This method really works, and will get rid of ALL the water within 12 hrs.

Eric Raven wrote: Have you had any issues with the boards handling temperatures that hot?

Maximum working temperature for polystyrene is 167 F, You want to avoid getting above that, but below that, it's fine. You will have a VERY difficult time getting your board that hot, even in an uninsulated, unvented attic on a 100 F day in the summer. The hottest an attic gets is about 150 F.

While I figure out how to vacuum the board, I have settled on heating up the board in a very simple way. I have a 33 X 17 heating pad underneath the board in its board bag. Able to move it around the bottom surface nose to tail in the bag. It has auto shut-off at 2 hours. Right under the pad it gets very warm to the touch, definitely greater than 100, I think these max out at about 140 at the highest setting. My paper wicks no longer get damp no matter how board is oriented, I have to get a scale to weigh the board, its feeling about the same weight as my other board which is supposed to weigh slightly less. If it is within a pound of the official weight, I'll be happy and will seal it up before the season starts.