Crack in anchor locker floor - water ingress into closed space - HELP!

[LiveCat6]

Hi Everyone,

pics here:

https://imgur.com/a/LrfcJF2

I'm experiencing some scope creep as I'm in the process of replacing my anchor chain, and decided to clean and paint my anchor locker, and found a crack in the floorboard which was letting water in when I washed the locker down.

I'm being told by some parties that I need to remove the floor and put a fresh board down and re-glass it in.

Others are saying I can probably get away with griding around the cracked area and glassing overtop of that.

I've also been told that methyl hydrate (or maybe its something else i['m not sure) can absorb water if sprayed onto the area that's been subjected to moisture ingress.

I got down into the access hatch as you can see on my one diagram and drilled a hole through the bottom of the vertical mini forward bulkhead to allow the suspected water to drain and boy did it drain.

Probably about 20 litres of water came out with about 1 litre of rust sludge at the bottom of the compartment. I've flushed inside that area as best as I could with freshwater.

Any thoughts on this? questions? experiences with similar issues?

I'm not worried that the floor is going to give way, and if it does it would be noticed the next time I anchor, but what i've been told is that that floor also acts as a horizonal brace to make the hull at the bow stronger.

Lots of force gets transmitted through the bow while sailing and while at anchor...

I dont want to cut corners but this also could turn into a huge ass job if I'm not careful.

Would appreciate any insight at all or further questions that I can answer to help shed light on this.

Thanks kindly!

[Island Time O25]

Not an expert by any means but the solution is obvious to my layperson's eyes.

Cut away the floor of the anchor locker leaving as much fiberglass around the perimeter as is nonrotten but at least 2-3" wide, may be 4" or more if possible. Do all the prep afterward i.e. sanding of the perimeter, etc. Epoxy
1/2" or 5/8" or even 3/4" marine grade plywood the size of the anchor floor on its both sides and edges with fb cloth. Prior to installing fill the blue shaded forward area with waterproof foam or some such. Same as used in many "unsinkable" boats. Don't skimp on fb tape around the edges and corners as the floor will support 100s of #s of chain+anchor. You may want to bolt through the perimeter to your new floor over it using the bolts as clamps for the epoxy. Easier done with the nuts on top.

The job sounds worse that it actually is. The worst part will be cutting away the old floor and prepping the perimeter for epoxying. To cut down on labor I would do "wet on wet" fb epoxying of the plywood. Then wrap it up in plastic sheeting to speed up cure time. I would not bother with heavy sanding afterward, if any, as it will be the bottom of the chain locker and not a seat or some such. Just enough to get it painted over.

[Tin Tin]

I would get a heavy grinder/sander and strip away the top resin layer of that floor and clean out the crack. Let it dry, hair dryer etc. I would then, fill the crack lay down a complete mat of heavy duty Fiberglass across the floor and up the side by a couple of inches and use epoxy resin - use a white resin dye. To me that would be a days work. Should last quite a few years.

[GordMay]

Methyl Hydrate [CH3OH] ≈ “denatured or methyl alcohol", or “wood alcohol”, or "methylated spirit", or “methanol” ...
Methanol is hygroscopic, meaning it absorbs water vapour, from the atmosphere.
I don’t know how well it would work, to help dry out wet GRP laminate.

[Fore and Aft]

LiveCat6 it's all been good advice, but I would forget using plywood for the base. Something like Coosa board would be a 100% better.
Cheers
https://atlcomposites.com.au/category/30/Coosa-

[Fore and Aft]

LiveCat6 I have been thinking more about your anchor locker bottom. Seeing your boat is a 1998 model she may be hardly worth doing an expensive repair if she's not been well maintained.
One quick and dirty way to repair that anchor locker is to grind the fiberglass floor and 6" up the sides. Then measure up a 3/4-inch piece of plywood to fit the floor. Lay two heavy layers of chop strand matt (600gm maybe) in polyester resin on the anchor locker floor, drop the new plywood floor on top while the resin is still wet, cove around the edges with some filler (q cell works well) then three heavy layers of chop strand matt in polyester resin on top of the plywood and up the hull sides. Stop for lunch. Then after lunch give the whole locker a quick grind and slap on a coat of flow coat. Flow coat is pretty thick, so one good coat will do. Next day load the chain back in and go sailing.
You will need a respirator and a fan for this job, polyester resin in a confined space really messes with your head.
Cheers

[Island Time O25]

I found that for small areas to be fiberglassed epoxy is so much easier to deal with than poly. The difference in cost between the two for a anchor locker floor repair is really not that great.

[stormalong]

Originally Posted by Tin Tin

I would get a heavy grinder/sander and strip away the top resin layer of that floor and clean out the crack. Let it dry, hair dryer etc. I would then, fill the crack lay down a complete mat of heavy duty Fiberglass across the floor and up the side by a couple of inches and use epoxy resin - use a white resin dye. To me that would be a days work. Should last quite a few years.

I agree with this but you should also open up that closed section all the way forward, dry it out and inspect the plywood. Also several layers of mat/cloth buildup would be appropriate. After all, you are dropping heavy, wet chain onto it.

Since you are a fresh water sailor just open it up with a hole that can be covered with an inspection plate, or just plan to leave it open. Wipe it as clean and dry as you can. Then put a ceramic heater up there for a few days to dry it out. Ceramic heaters can't get too hot or start a fire. Then inspect the wood for rot and water saturation. If it is dry and the wood is solid seal it with epoxy. Be sure not to seal wet wood. If the wood it rotten or de-laminated increase the fiberglass buildup above it.

[donradcliffe]

Had a similar problem on my 45 ft Beneteau, and just ground it clean and laid in some more glass with epoxy on both sides of the plywood. 15 years later, it was still fine.