How to check hull for water?

[Kauaiboy206]

I've got a 1979 sun runner with fiberglass floor and has no soft spots. There are predrilled holes with foam on sections of the boat and floor itself. When it rains, there is standing water over on some of the holes. Not sure how the previous owner stored the boat, but when I clear the standing water off and press on the foam plugs, it feels pretty soaked. Wondering how I would check the hull for water without tearing deck "minimally" and where would you recommend drilling or creating a hole.

 

[Scott Danforth]

on a 38 year old boat, plan on the foam being soaked and the stringers/transom/bulkheads being wet and rotten too

take a piece of pvc tubing the diameter of the hole, sharpen the edge, and take a core sample of the foam. if you pull it out and the foam is wet, you will need to tear into it to remove the wet foam

wet foam is failed foam that is sitting next to wet and rotting stringer/bulkhead/transom wood

I would also drill sideways into the box near the bottom if there is water in there, plan on firing up a saw. you may be able to uncap the hull, and pull the floor tub, however i doubt it would want to come out as it was intended on being in there for the life of the boat which for an express cruiser like yours is about 20 years

also, drill into the side of the stringer in the ski locker if the wood shavings are dry and light colored wood, then seal hole with marine tex epoxy putty. if the shavings are dark and wet, plan on firing up a saw

 

[Kauaiboy206]

on a 38 year old boat, plan on the foam being soaked and the stringers/transom/bulkheads being wet and rotten too

take a piece of pvc tubing the diameter of the hole, sharpen the edge, and take a core sample of the foam. if you pull it out and the foam is wet, you will need to tear into it to remove the wet foam

wet foam is failed foam that is sitting next to wet and rotting stringer/bulkhead/transom wood

I would also drill sideways into the box near the bottom if there is water in there, plan on firing up a saw. you may be able to uncap the hull, and pull the floor tub, however i doubt it would want to come out as it was intended on being in there for the life of the boat which for an express cruiser like yours is about 20 years

also, drill into the side of the stringer in the ski locker if the wood shavings are dry and light colored wood, then seal hole with marine tex epoxy putty. if the shavings are dark and wet, plan on firing up a saw

Thanks for the pointers, im gonna check the foams later today since we might end up having a break from all this northwest rain. The entire transom is pretty solid and consistent sound when I used a hammer and knocked around especially on the Lowest part of the transom near the bilge drain plug. I was thinking of drilling a hole somewhere near the bilge area and use a plumber camera for inspection so it's not as intrusive if the hull is good & would be easy to patch over. Like i mention, the entire floor is solid and there are no soft spots anywhere. So hopefully the foam is only surface wet and prevented water intruding into the hull.

 

[JASinIL2006]

Thanks for the pointers, im gonna check the foams later today since we might end up having a break from all this northwest rain. The entire transom is pretty solid and consistent sound when I used a hammer and knocked around especially on the Lowest part of the transom near the bilge drain plug. I was thinking of drilling a hole somewhere near the bilge area and use a plumber camera for inspection so it's not as intrusive if the hull is good & would be easy to patch over. Like i mention, the entire floor is solid and there are no soft spots anywhere. So hopefully the foam is only surface wet and prevented water intruding into the hull.

I hope you don't find wet structure, but I would not put too much stock in the 'knock test.' I don't think it's very reliable in finding rotten wood. Wasn't on my boat, anyway.