Filling in screw holes in fibre-glass hull...?

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ChasB

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By taking half the boat apart I've managed to track down an intermittent but damaging little leak. The previous owner of my boat replaced a corner fender
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and used screws that were too long, thus penetrating the hull. This may have been watertight at the time, but being fenders they've been knocked a few times and now water sometimes dribbles through.

I need to take the old fender off, clean out and fill the holes, and fit a new fender.

1) what do I fill the holes with?

2) any advice on re-fitting the fender?

I'll buy a new fender at the boat show and re-site the holes.
 
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That would be marine grade nuts and bolts then...

[/ QUOTE ]No, just either type 304 (above waterline) or 316 (below or waterline) stainless steel. /forums/images/graemlins/grin.gif
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"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
 
It's probably optimum to follow the straightforward glass/epoxy procedures in such as 'The Gougeon Brothers on Wooden Boat Construction', or in one of the many free pamphlets detailing the same, from any marine vendor of epoxy/glass repair kits.

However, the glass lay-up which has been exposed to water ingress needs to be thoroughly cleaned and dried. A cheap hairdryer ( every boat should have one! ) usually does the trick.

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No, just either type 304 (above waterline) or 316 (below or waterline) stainless steel. /forums/images/graemlins/grin.gif

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Please excuse me questioning the above statement but I've never heard, other than on this forum, SS being specified for marine or any harsh environment use in the above terms. Could you please explain to me why 304 SS, which can pit badly in marine environments, should be considered fit for use above the waterline and above decks? And why below the waterline is considered a more harsh environment than above?

Is it becasue we are only talking about little fixings here or would you use 304ss for say a pushpit?
 
Thanks.

actually it occurs to me that maybe drilling through is not such a good idea since it would mean getting access both sides if it ever needed replacing again and that's a real pain here.

Can i get the fibre glass filler at anywhere other than a chandlers? What's the best type?
 
316 grade is more resistant to chlorides hence is preferable to 304 grade for below the waterline use. Above the waterline, while there is salt spray around, 304 generally suffices although having said that there is bugger-all difference in the cost. In either case one should make sure the fasteners are fully passivated or failing that passivate them oneself before use - and don't use carbon or tool steel tools to fix the fastener.
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"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
 
I've used a car-based readymade grp repair paste with chopped glass fibres incorporated. It's cheap, goes off in minutes and is durable.

Hole in tender after storms 2005. Stuffed it full of polystyrene insulation board and dobbed the filler on top.

Tenderholed01.jpg


I didn't bother finishing off or painting on the scruffy tender principle

Tenderholed03.jpg


Hasn't leaked or deteriorated in 2 years.
 
Thanks for all the advice guys. Off to shops. Will fill later today, and thenlog in later to see if anyone's posted more advice on fitting the fender.

Still not decided whether to go for surface mount or drill through. All the others are surface mounted. I'm wondering if the boat should ever have a bad scrape against a wall whether it would be better if the fender tore away leaving minimal damage, rather than took some hull with it, like it might do if bolted through...

Fenders are meant to be a bit disposable aren't they?

Here's where my lack of experience in boating accidents shows up...
 
G'day ChasB,

You could drill out the old holes to remove any contamination then refill them with resin and Micro Fibres after sticking some tape on the inside to avoid a mess.

Then re drill and tap a thread for a suitable bolt, add some thread loctite to the bolt to ensure it stays tight, you can heat it and soften the loctite if you need to remove it later.

Any self tapper will most likely pull out, fall out or crack your gelcoat, threading or thru' bolting works thou.

I have used the 'New Metal' paste used to repair crossed or corroded threads in nuts or bolt holes with good results too.

Use an epoxy resin, stronger bind and stronger finish.

Avagoodweekend......
 
Corner jobbies....

If this was on a stern quarter, did the transom screws go into the reinforcement, and is it a plywood sheet, and has it become impregnated with water?

If so you could do with opening out the external holes a bit to have a dig about to check, and to aid drying. Once filled with Plastic Padding the fender will cover the mess up.
 
Re: Corner jobbies....

Thanks for the help guys - just got back from staying on the boat.

Two things have emerged...

1) the leak is not in fact from the fenders, but from somewhere else very close by where sections of the hull were screwed together. Fixable, but a couple of days work (including access and letting stuff dry). The kind of thing that makes you wonder why you ever chose ownership over rental...

2) there are six fenders - three on each rear corner. Each has ten screws, and they all penetrate the hull. they are not fitted in pictures in the original brochure, and appear to have been put on since. They're about 10 years old, above the waterline, and appear to be watertight. For now.

But now I'm worried. If they go wrong - after a heavy bump say - and start leaking you can bet it'll be just when it's most inconvenient. It could be that they are slowly allowing water to enter the hull itself, but how would I know?

60 screws...
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Andy, what do you mean by the 'reinforcement'. It's all glass fibre. Here's a pic:
fenders.jpg
 
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