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.