What's wrong with my topsides?

[Avocet]

What\'s wrong with my topsides?

Well, OK, the boat's topsides! (I know all too well what's wrong with mine!)

The boat is a white gelcoat-finished sailing cruiser from 1972. The lower parts of the topsides are still very good - in fact after a quick buffing, the bit under the transom but above the waterline looks like it has just come out of the mould!

The upper parts, however, are covered in fine cracks - just like impact damage or stress cracks but different. First of all, they cover a huge area (like about the middle 15 feet of each side (but worse on the Port side)). Secondly, stress cracks tend to look like a spider's web radiating out from the initial point of impact. These are much more random. In a different area, there are small pinholes in the gelcoat (well about 0.5mm across) and the cracks radiate out from them.

I've attached some pictures below (or at least tried to!) and I'd be ever so grateful for opinions from any GRP experts! I can sand the cracks away with fine wet-or-dry paper but they come back (I tried it on a small patch). The fact that they are nearer the gunwhale suggests maybe ultra-violet damage, but the decks haven't suffered (although these are grey-pigmented gel).

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[Jacket]

Re: What\'s wrong with my topsides?

I've got a similar problem on my boat (1978). I'd put it down to slight flexing of the hull when its being lifted out the water, squeezed between boats in a raft, and so on. Nearer the waterline the huls more sharply curved, so stiffer, which may explain the lack of cracks there.

I've no idea if the decks in a similar state, as its covered in non slip paint.



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[dieselhead]

Re: What\'s wrong with my topsides?

are those blisters on the port bow?, looks like old age to me, pin holes come from the original layup bing done badly but usually show up earlier, have they just come up or are the cracks just new? coul dbe a thin gelcoat layer getting old?

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[Avocet]

Re: What\'s wrong with my topsides?

Oh well, I can take some comfort from the fact that I'm not alone! I'm not sure, however, that I subscribe to the theory of these being repeated low-force stress cracks because they are worst near where the deck and hull join. I would have thought this would be one of the stiffest parts of the hull - especially considering there are two bulkheads bonded inside it and the crazing is no better or worse round these areas than any of the others...

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[Avocet]

Re: What\'s wrong with my topsides?

C'mon! there must be SOME experts out there!

Please?



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[tcm]

Re:GRP crazing

I had a look at google using "GRP crazing". Generally seems that it's not very serious, can be ground out and a new gelcoat sprayed on, but will need an expert with the right kit. If you sand down and then it "comes back" - you haven't ground it out - you've filled the bottom of the cracks with debris.

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[david_e]

Re: What\'s wrong with my topsides?

Think that because most peeps on here have newer boats they are probably not familiar with this, I'm not, except that I hope it doesn't happen to me!

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[oldsaltoz]

Re: What\'s wrong with my topsides?

G,day Ian,

The crazy paving effect looks like a bad layup problem, not uncommon with the onset of age. Can be caused earlier in the material under it is not stable.

The in line cracks look very much like stress cracks, the location of the bulkhead may not effect this as the stress is not on the bulkhead but the strip between hull/deck join and cabin, this would (I think) have ply glassed in on the underside, it might be time to check it's condition.

The holes and star cracks is not one I have ever seen, well, not that bad. However it looks like the holes are the start of the cracks, not the result of them. This (Holes in gelcoat) is another bad layup problem.

The good news is that all can be repaired, but I think I would look to stiffen a few areas, or at least establish why they are flexing now.

Lifting and storing on the hard will cause damage after a time, how much depends entirely on how well she sits and what support she has.

I hope this helps

Avagoodweekend Old Salt Oz /forums/images/icons/cool.gif

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[johnlilley]

Re: What\'s wrong with my topsides?

Looks like it could be brittle gel coat to. Some gel coats are harder than others, the hard gel coats give a very glossy finish when buffed but can be subject to UV deterioration, being very hard they can also be very brittle and the normal expansion and contraction with the inevitable flexing give results similar to those here. Quite likely the underlying laminate is fine. Strangely enough the gel coats which are soft and cannot buff to such a high gloss are often free from this cracking as they remain more flexible.
Hope this is of help. Unfortunately it is difficult to obscure as the cracks are not easy to paint over, they just keep coming back. A degree of gel coat removal is usually the only way followed by resurfacing and repainting.
Regards John Lilley

<hr width=100% size=1>John Lilley, John Lilley & Associates, Web site www.seasurveys.co.uk for osmosis /timber problems

 

[castaway]

Re: What\'s wrong with my topsides?

Are you quite sure the your boat has not been repainted(sprayed) at some time in a previous ownership?

The inside of my wheelhouse (which has been sprayed) has a similar finish, due to some failure in the paint...

Sounds like yr surface has given up due to UV exposure rather than impact or pressure IMHO

Regds Nick

<A target="_blank" HREF=http://www.yachtsite.co.uk/fairweather>http://www.yachtsite.co.uk/fairweather</A>




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