My boat takes on water in the starboard hull. Its not a lot usually I can get it out with 3 or more sponge squeezes after a day out. My concern is if its at the base of the daggerboard well one day it could get bigger fast so I want to figure out where the entry point is and try and stop it without resorting to gobbing on silicone seal everywhere. The top of the hull cross brace attachment was suggested but they spend zero time underwater. Has anyone pressure tested their hull or devised a positive/negative pressure test? Just under the upper rudder pivot there is a weep hole I could use for a test port. Another boat like mine has the same problem he hasn't found the spot yet.

My Bim A-cats had incidents of daggerboard trunk leaks- from jamming the partially-lifted board backwards. It puts a small split in the thin fiberglass trunk material at the aft- about 2 inches up. It impossible/difficult to find because the split is closed with water inside the boat, and does not leak. Ditto pressure in the boat & blowing bubbles- the split closes under pressure= no bubbles.
Gotta cut a hole in the deck behind the trunk.
I spent the whole 2004 Traverse City NAs with a stinkin' boat full o' water: couldn't find it, and dabbing goop & silicone was useless.

use the exhaust of a shop vac to blow air into the hulls - don't seal up the hose - just let it blow into the hulls to build a little pressure. Spray around all the potential leaking areas with soapy water and look for bubbles.

I recently had a leak in my daggerboard well that leaked more and more every time out. To fix it, I taped the bottom of the hull around and over the daggerboard trunk with packaging tape. I then cut out the daggerboard opening in the bottom with a razor blade. Using epoxy thickened with cabosil, I filled in the hole. Then, with the daggerboard also protected with packaging tape, I inserted it into the well to hold the shape of the opening. Once cured, a sharp knock with my palm knocked the board loose and I peeled off the tape cleaning any residue with acetone. No more leaks!

Jake definately has the right idea. For what it is worth extensive studies proove that Ivory soap makes more bubbles and there for makes it easier to see the leak.

I agree that is a good solution Jake, Did you use West Systems epoxy?
Sounds like you had more than the normal gap and did a fillet just around the the trunk where it connects to the hull. I was thinking that is the only place it could be.

When you find the leak and it's small. Say, a seam in the dag board well let go and it's hard to get to. Put the same vacuum on suck and feed some epoxy into the crack. Go easy on the pressure, just like Jake said but in reverse. It will suck the epoxy into the seam and fix you up. I've done that on several Hobie 18's and 2 Hobie 20's and it works like a charm.

J

That is just brilliantly simple!

Once I determine the leaky spot I have a small vaccum pump I can hook up to the hull and start it. Once I have the thing going I can add the epoxy to the leak and after I see it taking into the hole I can disconnect the power to the pump so it doesn't suck the resin into the hull away from the leaky spot. Sounds easy enough. Just have to tap out the weap holes to accept a threaded nipple and I'll be ready.

I like that vaccum approach... for the pressure side of things... bear in mind... 1 PSi is 144 lbs per sq foot. We test ship welded seems... we put in 2 psi... sometimes I hear welds breaking loose.

fiberglass will explode. 1 psi would be plenty to make bubbles. Also note that if the air flow is too strong... it will blow too hard to make bubbles. You should be able to hear it though

did someone say "nipples"?



(yes, it's almost quitin' time).

NO!

it was a only 1 nipple.