Soft Deck Safety

[dlochner]

If there's existing rot/wet core, then the fittings are rebedded, does the rot spread and if so, how fast?

Wet core and rotting core are not the same thing. Rotting cores are almost always wet, but wet cores may not be rotting.

So to answer your question, it depends. Rotting core gets to be an issue when the core has deteriorated to point where it can no longer keep the 2 skins apart. The deck will feel spongey.

 

[Project_Mayhem]

Wet core and rotting core are not the same thing. Rotting cores are almost always wet, but wet cores may not be rotting.

So to answer your question, it depends. Rotting core gets to be an issue when the core has deteriorated to point where it can no longer keep the 2 skins apart. The deck will feel spongey.

Yes, wet and rotting core are different. The question still remains, does it spread if no additional water is introduced?

 

[Don S/V ILLusion]

Yes, wet and rotting core are different. The question still remains, does it spread if no additional water is introduced?

Inevitably. Yes.

 

[dlochner]

Yes, wet and rotting core are different. The question still remains, does it spread if no additional water is introduced?

Depends on where the boat is located. In cold climates much longer than warm.

 

[dmax]

If the core is end-grain balsa, which mine is, then it spreads very slowly because of the grain orientation. If plywood, then it spreads much quicker because the grain is horizontal. On my boat, there was some rotten core around the chain plates and deck-fill openings which I was able to remove with various tools and get to solid wood. The moisture content was a bit high in the surrounding core (15 - 20%) so I applied a vacuum for about 50 hours and brought the moisture level down to 10%. Fill with epoxy and seal with butyl and it's better than when it left the factory. A moisture meter will tell you the extent of the wetness - a little bit (up to say 3 - 4 inches from a deck opening) is easy to deal with - more than that is a much bigger project. I looked at some boats that had areas of high moisture (20+ %) measured in feet. Higher than 20% moisture generally means the core is rotting.

 

[Project_Mayhem]

Depends on where the boat is located. In cold climates much longer than warm.

What about freeze cycles?

 

[FastOlson]

If there's existing rot/wet core, then the fittings are rebedded, does the rot spread and if so, how fast?

Are you just "asking for a friend"?
I would imagine that it would slowly spread, but have not had to deal with that problem. Once the moisture gets in, count on it causing rot and softness. Pretty sure the bad coring would have to be removed and replaced in any case.
Good luck!

 

[Project_Mayhem]

Are you just "asking for a friend"?
I would imagine that it would slowly spread, but have not had to deal with that problem. Once the moisture gets in, count on it causing rot and softness. Pretty sure the bad coring would have to be removed and replaced in any case.
Good luck!

No, just as a general reference. With fruits and veggies a freeze cycle can cause cells to burst. Perhaps it causes harm to the wood on a more minute scale than we realize?

@dmax Thanks for a great explanation! It makes total sense. I will use balsa for my next repair instead of marine ply

 

[jssailem]

"Soft decks" are caused by the lack of internal support between the outer and inner layers of fiberglass. Like the peanut butter and jelly are gone from the sandwich. Just 2 slices of bread (think fiberglass) are left. They will not fix themselves.

Freezing. Think lettuce. If you freeze it it goes to mush. If you freeze the wet soppy core it too goes to mush.

It is all about the water getting in under the fiberglass.
It is like that song by the Eagles... Hotel California

"Relax," said the night man​

"We are programmed to receive​

You can check-out any time you like​

But you can never leave!"​

Moral. Stop water from getting in under the fiberglass.

 

[FastOlson]

Moral. Stop water from getting in under the fiberglass.

And...... just like That. We're back to that "invisible elephant" again... !

 

[higgs]

If there's existing rot/wet core, then the fittings are rebedded, does the rot spread and if so, how fast?

Yes, the rot will spread. I have no idea how fast.