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Old 14-07-2012, 17:35   #16
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Re: Solid GRP decks?

Good point about the dimples under the fittings. They make perfect little saucers for holding water. As long as we are dicussing decks and coring, is plywood better than balsa or vice versa?

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Old 14-07-2012, 18:07   #17
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Re: Solid GRP decks?

Calibers are cored with marine plywood, with each piece individually encapsulated before putting it in the core. Heavy, but problems are rare.

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Old 14-07-2012, 18:18   #18
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Re: Solid GRP decks?

Plywood is better where there is compressability issues like under mast steps or where hardware like winches could be expected to be mounted. Unfortunately, it's more prone to large area rot problems should there be a leak. The water wicks along the grain of the wood eventually rotting over larger areas. Plywood is also much heavier so it counteracts, somewhat, the weight of the keel if used in the deck.

Balsa core is vertical grain so water intrusion is more likely to stay localized. Rot will spread more slowly as the water largely only migrates as the cellulose in the vertical grain cell walls break down from rot. Balsa core is pretty stiff but is compressable so needs backing plates, the larger the better within reason, to spread the compression loads and an easy hand tightening down fasteners. Balsa core is way lighter than plywood which makes for a stiffer boat though that's probably only a really significant issue for racers.

Given my druthers, I'd opt for balsa core but would install all the hardware my self. Essentially what I've done on my new, to me, boat. The core hasn't been an issue. My previous boat is going on 40 years old with a plywood core and is doing just fine. Of course, I installed most all the hardware on that boat and the subsequent owners were equally as careful with what they added to the deck.

Foam cores don't have rot problems but other issues. The biggest one is breaking down of the surface of the foam so the fiberglass laminate is no longer adhered to the foam. Negates the 'I' beam stiffening effect of having the core with the inner and outer FRP layups. Foam is also compressable though don't know whether more or less than Balsa.

Non cored frp layups have very low stiffness so need reinforcing at regular intervals. Not so serious with a hull as the loads are spread over larger areas. Still, many FRP boats used glassed in grid systems and/or laminate the interior furniture to the hull to give added stiffness. On a deck, the reinforcing grid has to be at much more frequent intervals as the point loads are way higher unless you only sail with 100lb models and stay at the wheel ordering your harem about. You can add stiffness by increasing the laminate thickness but it's a very heavy and inefficient way to add rigidity to a laminate.
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Old 14-07-2012, 20:19   #19
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Re: Solid GRP decks?

As for alternatives to the Rivals CAL's are lovely boats in IMO. I would look for a CAL 35 with a pilot house, they are rare but a friend of mine has one and it sails beautifully. I also hope to get one soon.
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Old 14-07-2012, 21:15   #20
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Re: Solid GRP decks?

Originally Posted by Yachtboy View Post
As such I find myself reconsidering the Rivals..

Rivals are seen is an older, high quality boat. But I would never suggest a Cal. Especially the last year they were made. They had many flaws.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming: Wow - what a ride!"
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Old 15-07-2012, 12:05   #21
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Re: Solid GRP decks?

I have an Alberg 30 and have found it to be a superb sea boat. I've been looking for a vertue for quite some time. Perhaps we should talk about trading boats. The Alberg is a supberb sea boat and an excellent liveaboard. Perfeft size for single handing.

Mine is well built - overbuilt actually, with 1" solid glass hull and cored decks. no blisters, still a large fleet of around 600 boats, mostly on the east coast, but some on the west coast, and a strongly engaged and active owners association and list serve. We exchange maintenance ideas and practical experience several times a week with other Alberg owners. Its great, like belonging to an online yacht club and virtual repair facility all in one shop.

Albergs were built with cored decks as coring adds tremendous strength to the layup, while keeping weight and cost down. Strength in fiberglass arises from the cross section, so using 1/2" core and a few layers of roving and mat produces a much stronger lamanite than using many layers of mat and roving. End grain balsa core is now often replaced with non absorbant foam core, which does not absorb water hence can not rot and delaminate--the old bug a boo of balsa core.

so dont worry about cored decks, just tap on them to see if they are bonded well. If not, cut out the top layer of glass, remove the coring material athen bed in new foam core with structural FG putty then glass back over the deck layer and fair it out Not a big deal really once you get into it.

BTW, a common fix for stanchion and otgher thru deck mounting is to drill out the stanchuion mounting holes say to 5/16 or 3/8", seal the bottom with tape and refill with epoxy to create a solid column, then redrill the mounting holes and re-install. creates a solid core underneath the base and seals the surrounding area to prevent water infilitration.

I would be interested in talking about a trade if you are looking for a FG cruising boat.
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Old 16-07-2012, 03:52   #22
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Re: Solid GRP decks?

Hi Glen, Thanks for your helpful reply.
Seem unable to read your meesssge. Perhaps drop me a line on note that # to be replaced with ampersand.
Forgive typos, Samsung Galaxy playing up!

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