EXPANDING deck repair

[mmuldoon]

I have researched this topic multiple times, so I felt comfortable enough to cut into the deck of my O'day 22 to begin replacing a wet core beneath the mast.

I first cut out about a 12" x 12" area immediately surrounding the mast. I expected the core to be wet and weak, but this core was POWDER (soaking wet powder). Is was to the point where the only tools needed for removal were a deep breath and a feather duster.



I then cut out a much larger area. It again came out easily, although it starts to show signs of resistance towards the edges.



MY QUESTION: Should I let the areas dry out a bit before further cutting/exploration? The size of this repair (originally expecting it to be maybe 12" x 36" at most) is starting to get bigger by the second. Is this deck salvageable?

Mike (on behalf of S/V Irie)

 

[CloudDiver]

Its a lot of work and a labor of love to replace a wet deck on a boat that has less over-all value that amount of labor plus materials you are putting into it. Some people might say its not salvageable and you should move on to another boat that has less issues to begin with.
That said, yes, if you are willing to do the work you can literally re-core the entire deck in sections if need be. You only want to open the deck in the flat sections in the manner that you have already done. Once you get close to turns, chines, and other 'geography' you have to switch over to cutting out a section adjacent to it but still be able to reach under the laminate with tools to remove old material and slide in sections of new core.
The $120 investment in a moisture meter is good to help you make choices here. Before you get too far in 'exploration' cutting its good to get a realistic idea of how deep this rabbit hole goes.
When I break out my moisture meter during the pre-inspection of a used boat for sale you should see the look on the faces of 'for sale by owner' boats as well as shady Brokers, LOL!

 

[rgranger]

@mmuldoon

Wow! I'm sure that made your heart sink. Thanks for posting those pictures. I've read up on this but have never tried it and I've never seen good illustrations before. These pics are very useful. I have a Rhodes 22 with a soft spot and in my research I ran across expanding foam EPOXY as a coring agent.

Here are a few interesting articles

http://www.sicomin.com/processes/foaming

http://www.matrix-composites.co.uk/products/sicomin-epoxy-resin/foaming.html

The stuff is very expensive but it is true closed cell and tough as nails. I imagined taking some plywood and make a crude fit and then simply filling in the remaining voids with this expanding epoxy. That way I would not need much but I would geta really strong bond between the core and the inner-outer skins.

 

[dlochner]

MY QUESTION: Should I let the areas dry out a bit before further cutting/exploration? The size of this repair (originally expecting it to be maybe 12" x 36" at most) is starting to get bigger by the second. Is this deck salvageable?

It won't dry out to any great depth with out removing the skin. All decks can be salvaged, the question is, is it worth the time, effort, and expense. One option is to just replace the critical sections, such as under the mast step and under the hand rails. The other factor is how good is a good enough job? How much sanding and fairing do you want to do? If you can live with less than perfect but usable, that will lower the cost and effort factors.

If you haven't already, check out the Sail Life channel on youtube https://www.youtube.com/channel/UC5xDht2blPNWdVtl9PkDmgA He has recored the entire deck on a 38 ft sailboat.

Also check out Boatworks Today: https://www.youtube.com/channel/UC0kDqq-pSzdqFUk3oTaHBuA

 

[DArcy]

It never ceases to amaze me how boat manufacturers used to think it was ok to use core material in areas of high compression like under a mast or anywhere with penetrations around deck fittings.

My boat had the deck under the mast step rebuild before I bought it. The area replaced was about the size of your larger cut out. I've heard of other C&C27s doing this as well. The core gets compressed over time which weakens the outer skin, cracking it and allowing water in. I also had some water ingress around my hand rails and had to remove core and fill with epoxy then drill through.

Just make sure you use a solid laminate such as FR4/G10 under the mast step when you re-build. Do NOT use foam or balsa core under the mast step. If you expand your area under any fittings, use solid laminate there as well and then drill through after layup.

 

[agprice22]

I agree that a moisture meter would help you. Perhaps write the numbers on tape and tape them on the deck, so you can map the area. It is going to be laborious. See Andy’s video on BoatWorks Today youtube channel.