How Far Rot Spread in Deck Core?

[Sailor_Grant]

I am working on fixing deck rot cause by an improperly installed oval deck pipe used for the anchor chain.

I have dug out the core as far as possible, however, I have not been able to get to dry core.

My question is: If I just seal it up, so no further water can get into the core, how far will the existing rot spread? Will this stem further damage, or just allow it to continue to cause issues?

Note that my boat is from the early 70s, and is extremely overbuilt - so even with wet core you do not feel squisheness given the thickness of the glass. This is more me preventing further damage, and potential structural issues if it spreads to the, for example, mooring cleats.

[S/V Illusion]

Originally Posted by Sailor_Grant

I have dug out the core as far as possible, however, I have not been able to get to dry core.

.

Don’t know what “as far as possible” means - a few inches?
The fix is generally to remove the FRP to define the extent of damage, replace the core and re-glass. Simply digging around an existing hole almost never tells you how far/how bad the damage it.

There are the usual “half-ass” “feel good” techniques like squirting some acetone into the space or using ‘get rot’ type stuff but neither will ensure the problem doesn’t get worse and doesn’t provide any assurance you fixed anything.

[SailingHarmonie]

Originally Posted by Sailor_Grant

I am working on fixing deck rot cause by an improperly installed oval deck pipe used for the anchor chain.

I have dug out the core as far as possible, however, I have not been able to get to dry core.

My question is: If I just seal it up, so no further water can get into the core, how far will the existing rot spread? Will this stem further damage, or just allow it to continue to cause issues?

Note that my boat is from the early 70s, and is extremely overbuilt - so even with wet core you do not feel squisheness given the thickness of the glass. This is more me preventing further damage, and potential structural issues if it spreads to the, for example, mooring cleats.

It will keep going until it runs out of wood to rot. Fungus attacks the wood, and over time turns it to dirt. The encapsulated water then is free to migrate to fresh wood where it allows the fungus to decompose it, and so on and so on.

If you were extremely lucky, you would have caught this early engough that you could have gotten to dry core just by digging out what you could reach through the hole. You were not that lucky, now you have a bigger job ahead of you.

As Illusion says, the only way to fix this right is to strip off the top (usually) fiberglass layer until you find dry core, clean everything out and put it back together again. Counting on the urban legend of 1970's boats being so overbuilt you can neglect basic maintenance is a bad idea. We had to do this over about 25 sq feet of deck. It was a messy, difficult and expensive job. But for an ocean-going boat was essential to maintaining its structural integrity.

[boatpoker]

Sailor-Grant ... you might pick up a few hints here ...
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