scarabman

iTrader: (1)

Working on a friends boat. We pulled a trim tab to fix some corrosion on the backing plate. It appears as though some water was weeping in around the corroded area but the true extent is unknown. That being said, the wood in the transom is NOT saturated. There was no corrosion on thru bolts on the tab or surrounding hardware which we also pulled. A small dental pick CAN be inserted into the wood with some effort and the wood cannot be picked apart without effort.

Realizing that probably a great percentage of boats out there have had some type of water intrusion at the transom and given the situation we encountered, it got me to wondering: When do you call a transom rotted?

c_deezy

iTrader: (1)

That doesn't sound too bad. I would try putting it under vacuum to try and pull the moisture out. Not with a shop vac, with an actual vacuum pump set up.

Only way to tell for sure is to knock on the surrounding area and see how it sounds, and if it sounds hollow/dull take some core samples of the suspected area.

scarabman

iTrader: (1)

Tapping around on it definitely produces some different pitches, some of them sounding a little hollow when you get away from intersecting structures like stringers, corners and bottom. None produce a dull thud though. They all sound sharp, some just a little more hollow than others?

scarab63

iTrader: (5)

I'd half core it from the inside.
Measure transom thickness, split that in half & reference tape on the drill bit for you mid point.
You can plug em in the bilge and paint or easily hide with rigging like drive resi bottle or msd etc....

scarabman

iTrader: (1)

Not sure I follow? Drill a bunch of holes and use penetrating epoxy, or "core" it with something else?

scarab63

iTrader: (5)

If the transom is 2 1/4" thick.

Mark your drill bit @ 1 1/8"

Drill half way thru the transom from the inside in the places you've got doubts to check the woods integrity.

If all checks out well fill the holes with dowls soaked in resin.

Then re paint bilge, or touch up around your work, or plan your drills so they'll be hidden by rigging

scarabman

iTrader: (1)

Got it. You meant core test. But this kind of brings me back to the original question. Once I do some test holes, what should the wood look like? We know some water got in, just dont know how much. We know it is not saturated. I have read the wood should come out in curls if it is good, but plywood never drills with curls, it is more like small chips?

vintage chromoly

iTrader: (3)

if the wood that comes out is wet and squishy, you need work. if the wood that comes out is nice and dry, you are good to go. you will know when it comes out what you are up for.

also, if it smells moldy, you need work.

scarab63

iTrader: (5)

+1 I usually take a pick or screw driver. If you can easily keep plucking chunks out NFG. good luck. Post results.
MD

prostock85

I use a plastic handled screwdriver. I would use the handle to knock around certain areas. On any good/not rotted areas it will have a bounce to it. Any thing that's rotted/delaminated has a major difference in sound and lacks the sharp sound and bounce. Obviously things change to a sharper crack as you near stringers/corners. Using this method I've passed on many boats..

(I am in no way a pro, just sharing my method)