Using Ethylene Glycol on rot damaged GRP covered stringers and bulkheads to arrest further decay

[bajansailor]

Re the stringers, it is possible to have fibreglass 'top hat' stringers that are as 'strong' as (if not stronger than) wooden stringers that are overlaminated with fibreglass.
So Martin could consider just using a former (if he is replacing stringers) to give the shape, and getting the strength from the fibreglass instead.

 

[gonzo]

Sistering stringers is possible and less work than removing the old ones. However, it depends on having access and if there are things like fuel tanks in the way.

 

[philSweet]

It attracts water and doesn't arrest decay. It can stabilize stuff by displacing water so that there is less dimensional change due to drying. This is normally done in the archeology and for museum-curated stuff. Also, you may be confusing EG with PEG or PEO, which is nontoxic.

 

[trip the light fandango]

Trip the Light Fandango,

I'm glad to see your response on drilling holes/injecting resin. I have a 32ft Sutphen "cigarette" type boat made for rough water. Twin 502's.
That's exactly what i am doing in the transom. Just trying to get something solid between the fiberglass laminates in the transom especially where the multitude of items that are attached and the laminates squeezed together by bolts (2 trim tabs, 2 hydraulic steering brackets, besides the drives, thru hull exhaust, and the usual other stuff. Tapped with wooden stick everywhere, and drilled quite a few 3/8" holes to check for rot where suspected. But doesn't take too long to do. Completely drying it out first.

This boat has been thru a lot of rough riding before i saw one small transom crack at a stringer, so it must be a very well built transom for the engines/drives to stay perfectly aligned after that much abuse even with the rotting spots. It does have offshore front engine mounts. Next time i will pull both motors and everything, but for now, it's holes and injected resin with a filler, and a good repair at that crack at the top of one stringer.

Thanks for your suggestion. Should work for a stringer as well which I've seen hold up just with the fiberglass and some of the wood gone. Glass is tough. Glad to see somebody mention this. You don't see this done much. But since it's held up, and I now keep the transom dry since I've bought it, I really believe this will make it last quite a while. Mostly to keep the existing laminates in there place, although i agree, not at all as strong as everything properly glued together, but should be more than enough.

Kurt

How well the 2 skins are keyed together via the plugs is important . I'm pleased you like the idea, an update after its been in service for a while would be great . Also there is now a product by sikoflex that chases out water and converts gaps into a polyurethane in concealed space like underneath bathroom tile etc which might be worth looking at , epoxy plugs would still be required. regards.