Best Way to Probe For Wet Foam/Wood

[seedlings]

1979 AMF Crestliner Muskie 550 14' - I know the transom is wet, not powdery rotten, but dark and damp at the bottom. The floor is solid all the way back. The plan is to replace the transom with NidaBond in the off-season.

I need to know the best places to probe for wetness to determine how extensive the water intrusion has been. The back corners are filled with foam. Do you think this corner foam was poured on top of the floor, or do you think the floor was placed after the foam was poured? Drill into the foam compartment as low as possible to check the foam?

Looks like the stringers are visible there on either side of the sump. What would be the best way to check stringers? I know some tri-hulls don't have wood stringers, just foam or sometimes foam stringers. Would there be more than two stringers?

Any advice would be appreciated.

CHAD

 

[rickryder]

Re: Best Way to Probe For Wet Foam/Wood

Best way to check stringers is to drill into them and look at the shavings. The foam.....take a 2" hole saw and make an access hole in the top of the deck....get a piece of pipe....(I like a metal tail piece from the plumbing dept) and push and twist it down into the foam. Pull pipe and you will have a foam core sample inside the pipe. Use a stick and remove core from pipe. Squeeze the foam and look for water.If the foam is wet you will need to pull it all out....it will never dry out.

Be careful while drilling and don't go through the hull.

 

[GT1000000]

Re: Best Way to Probe For Wet Foam/Wood

Hello seedlings,

rickryder has you headed the right direction...

Just want to add a couple more ideas...

Take your samples from as low and as far back as you can...

You can also use a piece of 1-1/2 inch thin wall PVC to make a foam core drill...click on the attachment below

when drilling into the transom, most are about 2 inches thick, so put a piece of tape about 1-1/2 inches on the drill bit as a stopping point so you don't go all the way through...

If you are fortunate enough to find nice dry wood and foam, you can seal up the transom holes with 3M 5200 and coat the foam plugs and re-insert them in their holes...

Best of Luck,
GT1M

 

[seedlings]

Re: Best Way to Probe For Wet Foam/Wood

Choosing the location of the (first) hole was my dilemma. Here's how it went.
1) picked this spot because I thought it was clear of the stringer, and as far back as drilling clearance would allow. I had a 1" hole saw and a 4", so I chose the 1"

2) This spot actually caught part of the stringer. Maybe that's good. I used some 1/2 copper pipe to do a core sample at an angle to clear the stringer. I tapped the pipe and twisted until it was making contact with the hull, then wiggled and pulled out. Left to right you see:
Decking
Fiberglass (top of stringer? Pretty thick)
Part of the stringer (no water, good wood)
Foam (no water, no discoloration)

Here's the hole. I can't find any dampness in there:

So... where is the next place to check? Make a similar hole behind the battery on the other side?

Thanks for your help,
CHAD

 

[rickryder]

Re: Best Way to Probe For Wet Foam/Wood

Yes check the other side also.

 

[seedlings]

Re: Best Way to Probe For Wet Foam/Wood

Yes check the other side also.

I apologize for all the questions, but sure appreciate your guidance. I'm hoping to make as few holes as possible but be confident about the findings.

CHAD

 

[seedlings]

Re: Best Way to Probe For Wet Foam/Wood

I was going to fill this hole with a PB mix of glass mat (chopped myself) and resin. Is this OK or will the resin melt the foam?

CHAD

 

[GT1000000]

Re: Best Way to Probe For Wet Foam/Wood

I was going to fill this hole with a PB mix of glass mat (chopped myself) and resin. Is this OK or will the resin melt the foam?

CHAD

It might, do a test on the plug that you pulled out, mix a small batch of resin and drop the foam plug into the container...if it doesn't melt away you should be good to go...

 

[BonairII]

Re: Best Way to Probe For Wet Foam/Wood

While your in the bilge area...wouldn't be a bad idea to replace the corrugated hose with smooth walled hose and re-route it a bit.

Corrugated hose reduces water flow by quite a bit(up to 30% loss from what I read). And making the hose shorter and more direct to the outlet will increase water output.

Just a thought.

 

[seedlings]

Re: Best Way to Probe For Wet Foam/Wood

While your in the bilge area...wouldn't be a bad idea to replace the corrugated hose with smooth walled hose and re-route it a bit.

Corrugated hose reduces water flow by quite a bit(up to 30% loss from what I read). And making the hose shorter and more direct to the outlet will increase water output.

Just a thought.

Thanks. There has never been enough water in the bilge to use the pump, but I may replace the tube.

CHAD