Deck Repair

[davidpm]

This is my crude drawing of the construction details:


This is the hole in the topsides where the chain plate got pulled out.


As you can see the damage is exactly at the meeting of two ceiling liners that I think must be partly structural as the bulkhead is screwed to one of them.

I'm thinking of opening the hole up more on the deck as there is going to be a patch there anyway so what difference if is 6" square or 12" square and patch the deck all from the top. The deck is only about 5/8" thick with a 1/8" skin on both sides of 1/2" balsa so if my patch ends up being solid that might be a good thing. What do you think?

[sailingdog]

I would replace as much of the core as possible, while leaving the area immediately adjacent to the chainplate solid glass. Also, make sure fastener holes are properly potted or in the solid glass area.

Is the overhead liner glassed to the cabintop?? Or is the bulkhead glassed to the hull?? If the bulkhead is glassed to the hull, then the reason for the bulkhead being screwed to the cabin overhead liner may be to support the liner. If the liner is glassed to the hull, then the screws may be to support the bulkhead.

[CalebD]

Wont you need to take down the liners in your diagram to get at where the chain plate is bolted to the 5/8" ply bulkhead? Is the bulkhead tabbed to the hull and in good shape behind the liners?
The hole suggests that maybe a bolt or 2 were pulled through the deck when the chain plate came out. Makes me wonder if the bulkhead may be compromised.
By all means open up the hole a bit as you will want to bevel it for your repair anyway. I find that a grinder with a sanding disc on it works well at shaping fiberglass and wood - lots of dust though.
It looks to me as though that wooden toe rail could use re-finishing. Looks like old Cetol Marine on there now.
Good luck.

[davidpm]

Originally Posted by CalebD

Makes me wonder if the bulkhead may be compromised.

Definitely compromised. A 6" square piece is rotted out.
That I can repair OK without messing with the liner.

I'm over-thinking it I'm sure. It's one of those open it up and see what you get jobs I'm afraid.

[davidpm]

Originally Posted by sailingdog

Is the overhead liner glassed to the cabintop?? Or is the bulkhead glassed to the hull?? If the bulkhead is glassed to the hull, then the reason for the bulkhead being screwed to the cabin overhead liner may be to support the liner. If the liner is glassed to the hull, then the screws may be to support the bulkhead.

The bulkhead is glassed to the hull. I showed a clearance between the liner and the overhead that does not exist in my drawing so I wouldn't be surprised if they put a little adhesive between them.
Good point though.

[davidpm]

Originally Posted by sailingdog

I would replace as much of the core as possible, while leaving the area immediately adjacent to the chainplate solid glass.

If you are working on such a small area maybe a foot square do you think it matters much if the repair ends up being solid glass. Probably more work to make a 5/8" think panel of glass than I'm imagining. I'm not likely to find a single square foot of core the right thickness though. I could just use the chop saw and slice off some 1/2" long pieces of soft pine which for such a small area would probably behave the same yes?

[sailingdog]

I'd point out that solid glass is generally not as stiff as a cored laminate of the same thickness. The main reason companies use solid glass for areas where the deck is highly loaded is that the solid glass resists compression loads better than a cored laminate and doesn't have the issues with water intrusion. However, given the same thickness, a cored laminate is usually stiffer and lighter.