Damn you Miami!! Soft spot question

[NorthernMac]

So I have a 4x4" soft spot on the cabin roof, knew it when I got the boat, surveyor thought delam, but I still have to drill and see.

I noticed a few more small ones by the cockpit, but pushing down it feels like there is a gap then its solid. Not sure if being a NE boat that has been in the SE sun caused this...?

Whats the chance its just delam with no rot, and what would be the difference in a proper (see strong and invisible after finishing) repair?

Thanks,

[SVHarmonie]

Rot is caused by water.

If the area of concern is not close to any possible water leaks, then it MIGHT be delamination. The problem: if it IS delamination, then the cause is bad construction in the first place. Which applies everywhere even in those spots that haven't gone soft--yet.

[NorthernMac]

Originally Posted by SVHarmonie

Rot is caused by water.

If the area of concern is not close to any possible water leaks, then it MIGHT be delamination. The problem: if it IS delamination, then the cause is bad construction in the first place. Which applies everywhere even in those spots that haven't gone soft--yet.

Huh... Not too much water, I do know for the cabin top its a deck step mast and it did live on the hard with the mast off for a bit

Boat is a Legnos, and from what I read they were built well

So what would be the best way to execute repairs?

[coopec43]

The construction is solid glass.
https://sailboatdata.com/sailboat/mystic-catboat-20


Have you checked the forums?

https://www.cruisersforum.com/forums...p/t-23484.html

Legnos Mystic Cutter Feedback? - Cruising Anarchy - Sailing Anarchy Forums

https://www.sailnet.com/forums/boat-...stic-30-a.html

[thruska]

Well built or not, if the mast was stepped and at some time not tuned properly and faced with undue stress you can have damage to cabin top.
You could also have had leaks in poorly bedded fittings on deck which lead to rotten core. Water finds its own course and direction of travel.

[Starblossom]

I had the same problem more then 20 years ago in a very large area of the cabin top.. I snapped chalk lines to form a grid 2" on center.
I drilled holes from below to a depth just below the upper laminate. I used heat lamps and fans to let any moisture evaporate. Then with 3 friends: 1 mixed west system epoxy and #406, 1 loaded syringes, 1 injected the syringes with epoxy into the holes until the void was full, and the last one followed behind the insertion of the epoxy and inserted plugs into the holes so the epoxy wouldn't run out.
The results of the repair is that the boat is now stronger and firmer then its was new 37 years ago. It is a messy repair. I suggest drop clothes everywhere, gloves, masks, and good friends to help
Good Luck

[NorthernMac]

Originally Posted by Starblossom

I had the same problem more then 20 years ago in a very large area of the cabin top.. I snapped chalk lines to form a grid 2" on center.
I drilled holes from below to a depth just below the upper laminate. I used heat lamps and fans to let any moisture evaporate. Then with 3 friends: 1 mixed west system epoxy and #406, 1 loaded syringes, 1 injected the syringes with epoxy into the holes until the void was full, and the last one followed behind the insertion of the epoxy and inserted plugs into the holes so the epoxy wouldn't run out.
The results of the repair is that the boat is now stronger and firmer then its was new 37 years ago. It is a messy repair. I suggest drop clothes everywhere, gloves, masks, and good friends to help
Good Luck

So no replacement of the wood, just dried it out, injected and plugged?

Are there any drawbacks to this method?

Also you did this from inside the cabin drilling up and stopping before the glass on the top of the cabin?

[Starblossom]

Correct- epoxy filled all the voids where there was either foam or wood.
Injected in each hole until you couldn't put anymore epoxy in.
I don't know of any drawbacks. The repair made the boat better then when it was new.
I repaired from the inside since I didn't want to redo the outside finish of the boat.
It is much easier and cleaner to repair from the outside if you don't care about the outside finish of the boat. You can eliminate the person plugging after the injecting.
You put a stopper(?) on your drill bit to make sure you don't penetrate the upper fiberglass, or if you work from the outside the inner fiberglass.
The repair requires very little skill to do a satisfactory job.
Good Luck