Oday 25 Cabin Core Replacement

[glong3]

This past weekend I found quite a bit of core rot under the mast step. I cut open the top layer of fiberglass and ended up removing a rather large chunk of my cabin roof, from the mast step to both port and starboard handrails. All core in that area was either soaked or rotten.

I was wondering what core material everyone is redoing their cabin top in. Is everyone putting in more balsa with the plywood core at the mast step? Or are they people out there building up the fiberglass layers to the thickness of the rest of the cabin or using foam core?

 

[Erieau]

I used end-grain balsa for the side deck areas that needed the "treatment." Wet and extremely rotted around poorly installed pumpout fitting and 'plates.
On the cabin roof, only the plywood mast base was wet (not rotten), and was separated from the dry balsa core surrounding it by a thin layer of resin. Lucked out.

 

[RichBone]

I originally only did the area under the tabernacle with fiberglass (why use wood) but found out that the step still depressed even with the compression post underneath holding it up. The starboard side held up but the port side was pushed down by the mast. The step had to be tied in with the surrounding core.

I ended up doing a larger area with glass and epoxy. Using thick fiberglass it built up fairly quickly. I finished it off with Evercoat 27 (sets up fast and easy to sand).

You could lay in some pieces of plywood to fill up the space if it's a larger area. Maybe 3/8 ply to have room for cloth on the bottom and top.

 

[glong3]

Thanks for the pics RBone. The area I am dealing with is from about where your handrail starts on to where your blocks are, all the way across. I think I have enough fiberglass to build up the whole area instead of using more wood core, if I chose to go that route. I even thought about doing a larger piece of plywood under the mast step and just build up the sides with just fiberglass. Any thoughts on this?