Replacing front wooden grabrails on cabin roof

[Murv]

Normal service resumed, me asking for help again...

Our boat has two wooden grabrails on the front

Which are a bit rotten and need replacing.
They're held on by three large self tapping screws which are heavily countersunk into the wood and then sealed in with some sort of plug.
Dug the plug out, the screws just turned and wouln't come out.
So, sawed through the timber, with the idea being to wind the screws out with molegrips.
And, they still won't come out.
Pulled the carpet down inside the cabin underneath them, there's no access to the underneath at all.
There's definitely something stopping the screws coming out, maybe a plug of epoxy or similar which is just turning inside the moulding?
So, I've sawn the screws off, pushed the remaining bit down inside the moulding and the plan is to drill the replacement timber, find some short, but wide, screws with a coarse thread and wind them into the GRP.
What can I inject into the moulding to give the screws a better hold?
I was thinking along the lines of silkaflexing the new timber on, as well as fixing with screws, and then filling the hole with epoxy, coating the screws with oil so that the epoxy won't stick to them and then winding them in with the expoxy wet.
This way, they can be removed if the timber needs replacing again.
Will that work? or would it be better to fill the void with silkaflex, wait for it to cure then wind the self tappers into that?
Any other ideas?

Quick picture of the mouldings that the timber fixes to, the tape is just there to stop water ingress

I'm fairly sure that by winding the screws into wet epoxy would hold the rails firmly enough, but don't want to be (or any new owner) stuck with the same problem in a few Years time when the timber needs replacing.

Any advice, as ever, would be greatly appreciated

 

[tolhurstorganic]

It may be the screws go into a wooden block fibre-glassed in, the blocks may have rotted with water ingress. Perhaps drill a larger hole adjacent to check. If that is the case then ideally remove the rotten timber and replace with hardwood or fill voids with resin/filler and bolt right through. Through bolting would be the most secure method, handrails can occasionally take extreme loads, screws only are not very strong.
Is it a wood screw or machine screw, if latter maybe the captive nut is no longer captive and spinning around?
Sikaflexing on will certainly improve the strength but if the rail is not securely fixed down then water will get in due to slight rail movement, with resultant damage down below. The rails really do need to be very secure.

 

[sailorman]

what timber do you propose to use for replacements

 

[Murv]

Thanks for that, the only snag with bolting right through is that I'd end up with the ends of the bolts in the cabin which I'd like to avoid if possible, may be the only solution though.

I've got two strips of Iroko to replace it, I couldn't get any teak.

 

[Seajet]

Murv,

just a thought, but in the interests of safety and avoiding the rot happening again in future, how about stainless handles ?

Shouldn't be too outrageously expensive, and through-bolts & nuts could be sunk flush, counterbored with penny washers, into the deckhead ?

 

[Murv]

Did investigate that option, off the shelf items won't fit (440mm spacing) and a custom build was over £1000.00
A friend of mine could knock me up some simple bars, but they'd be restrictively heavy.

 

[Rossynant]

You may investigate further. Quite possibly there are wooden blocks put into the laminated "recesses" in the main shell and just glassed over on inside. Not that I would guess why should they be glassed then For cost/time saving?
In such case best idea is to take rotten wood out an use normal bolt/nut + backing pad. Bolt end with nut will be in recess, but accessible under the panelling or whatever you have there. This is proper way. Anything just screwed down from above on deck is cheap but inadequate way of securing...
Might be as well this was done proper way, so you have a bolt and nut underneath is turning freely. Or whatever.

 

[Murv]

OK, thanks, will investigate again.
The cockpit has carpet stuck on the roof, I've pulled this down and can see no sign of the recesses being glassed over but it may be hidden under the remains of the glue/felt left on the inside of the roof (deckhead, another word learned!)