Keel Band for Workboat

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Stoshak

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We have a simulated clinker GRP workboat, about 19ft with an inboard engine.

The keelband appears to be mild steel (may have been galvanised originally), about 2in by 1/4, running from stem to stern. It is badly corroded and needs to be replaced. Not easy to see how it is held on.

We probably need to replace it with a similar galvanised section, but how to attach it?

Countersunk head fasteners, because she is frequently beached. Through bolts best I suppose, but could we get away with screwing into the keel?

Advice much appreciated
 
Albeit on a somewhat smaller grp boat which I could invert, I used water bar from a builders' merchant - already galvanised. I then, against the advice of this forum, epoxied it in place after abraiding the keel. Still in place when I sold boat three years later.
 
Stoshak said:
Countersunk head fasteners, because she is frequently beached. Through bolts best I suppose, but could we get away with screwing into the keel?
Click to expand...

I've got the same grp/clinker set-up as yourself, except the hull is just 15ft long. The keel band is one piece flat s/s, and has to be flat as, although there's no keel rocker as such, the keel (and band) does turn upwards at both ends. From memory it's about 1.25 to 1.5" wide - as you say, held on by c/sunk screws of some kind. There's a full-length plywood floor a few inches above the keel, with the void being filled-in with injected foam - so any re-attachment would need to be done from underneath only.

The boat is some 20 years old and has been worked hard and no doubt beached frequently. But I'd say the keel band is original and still doesn't need replacing - but if it did, then I'd drill slightly oversize holes and fill em with epoxy putty, then insert the screw (coarse woodscrew, I guess) and support from beneath until the epoxy had set.

If you've got access from above, then through-bolting with epoxy or 3200 lining the holes would make a superb job. If you can afford it, I'd go for a stainless band, then you can forget all about it ...
 
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Stoshak said:
We have a simulated clinker GRP workboat, about 19ft with an inboard engine.

Advice much appreciated
Click to expand...

Here you go,bottom plate Mild steel 1/2" thick then all galvanised, bolts 15mm Stainless steel, not cheap but will last for ages.

Mike

keelshoe006.jpg
 
Bobobolinsky said:
How about cheap softwood sacrificial band, screwed and Sika'd in place, Fixings counterbored and filled with Sika. When it thins replace it
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Another approach (seeing as the OP wants a 2" wide keelband) is to bond lengths of car seat-belt webbing to the keel soaked in epoxy - as you say, if and when it thins, replace it - or simply add more to it. I did this to the keel of a tender donkey's years ago, and it ain't worn out yet.
 
Caer Urfa said:
Here you go,bottom plate Mild steel 1/2" thick then all galvanised, bolts 15mm Stainless steel, not cheap but will last for ages.

Mike

keelshoe006.jpg
Click to expand...

If frequently beached the galvo will soon disappear. Beach boats here, up to about 4 tons and 25ft have 12mm mild steel band with lugs, (or side plates) the band is wider than the keel so the lugs sit on top as in the pic and don't snag the ground or launching timbers. Having a wooden false keel is a help, if the lugs are bolted to the GRP keel and any slack ensues they wear the holes oval with repeated launch/recovery. Best is instead of lugs, side plates end to end, so no detritus/shingle can get between the steel and GRP/wood. I did one boat with channel iron, I formed the wood keel into it then put the wood on the boat, but you need a good tight fit as the bolts will not compress the channel.
I did my 32ft 12 ton keel band, lugs bolted through the GRP keel. Don't forget the electrical bonding.
 
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