GRP v Aluminium?

GRP v Aluminium

  • GRP

    Votes: 47 72.3%

  • Aluminium

    Votes: 18 27.7%
  • Total voters
    65
PhilipH said:
ah yes, maturity .... forgotten how mature and reasoned the posts are on here ... and the penetrating insults ... and the knowledge and expertise ... and the helpful comments ... oh, why bother?
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Nothing is so guaranteed to enrage an otherwise genial man as a criticism of his choice of boat. One poster on this forum virtually exploded with rage when I suggested that Prouts are slow. And the worst criticism of all is 'ugly'.
 
I once sailed on a boat that was made from riveted bronze. The plates were butt jointed above the waterline and lapped below.

Though I'd like an ally boat for cruising, I can repair GRP easily.
 
prv said:
From what I've read (including an article by Tom Cunliffe, whose last boat Westernman was built this way) the problem is more to do with fittings. So skin fittings, chainplates, glands and bolts connected with the rudder and prop, possibly the hull-to-deck joint depending on how that's constructed. Obviously dozens of fittings on deck if you build the deck using the same technique but I don't know if that's normal. Of course these can all be installed correctly and well maintained so that they never cause any problem at all - I'm not suggesting that this is a fatal drawback of the technique by any means. Just that no boatbuilding material is perfect and worry-free.

Pete
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Philip Walwyn, who started building epoxy coated timber strip catamarans, decades and eons ago, and recently built KATE (12 metre America's Cup First Rule gaff rigged yacht) the same way use a great method.

He would drill a way to big oversized hole, fill with solid glassfibre/epoxy, let it dry then drill correct size hole and screw or bolt on the fitting etc.
 
Rum_Pirate said:
Philip Walwyn, who started building epoxy coated timber strip catamarans, decades and eons ago, and recently built KATE (12 metre America's Cup First Rule gaff rigged yacht) the same way use a great method.

He would drill a way to big oversized hole, fill with solid glassfibre/epoxy, let it dry then drill correct size hole and screw or bolt on the fitting etc.
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Yes, this is consistent with the Gougon brothers research also.
 
yodave said:
If you take cost out of the equation, would you rather have a GRP or aluminium yacht?

(Yacht = sailboat between 30 - 40ft)
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You can never take cost out of the equation but for me it would be grp or better epoxy every time.

1/ insulation
2/ corrosion
3/ ease of repair
4/ appearance

I looked at buying an Ovni but did not because my experience in the metals industry told me that dealing with paint on aluminium would be a nightmare, and because I did not know what could be done to give an invisible reapoir to an ally hull after a dent. You local panel beater from the car repair place?

There is a reason that 95% of boats at all price levels are made of grp
 
VicS said:
Titanium.
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:cool: :)

Did hear of one once, out of a Russian submarine factory from off cuts. Might have been folklore though.

As for metal, I'd like an aluminium maybe , live on a steel at the moment. Ovni's are nice, a possibility of problems with a lifting keel could be offset by being able to run it up a beach anywhere for a scrape. Also no one has mentioned a big plus of metal in being able to still keep the drips at bay even after weeks of pounding across an ocean.
All from a cruising perspective, coastal seems to have "pretty" as a major consideration. Weeks away from land this opinion can sometimes morph from "pretty" to "Really $%#^@&* Strong!!!" :)
 
Rum_Pirate said:
Philip Walwyn, who started building epoxy coated timber strip catamarans, decades and eons ago, and recently built KATE (12 metre America's Cup First Rule gaff rigged yacht) the same way use a great method.

He would drill a way to big oversized hole, fill with solid glassfibre/epoxy, let it dry then drill correct size hole and screw or bolt on the fitting etc.
Click to expand...

Actually, the best thing is to build with no (or very very few) bolt holes at all. This is one of the brilliant thing about aluminum - you can have a truely watertight deck with (almost) no holes thru it. You can do this with glass also but almost no-one does because it is more labor intensive. But integral carbon chainplates for instance are well proven - reliable and don't leak at all. As are integral stanchion bases (several methods but g10 rod is IMHO the best). For genoa tracks you do as in aluminum - flat bar integral to the deck with with pre drilled holes with helicoils - you can in fact built completely integral tracks but it is rarer - more labor and if they are damaged it becomes a bit of a pain to replace them.

The KEY question about boat building is NOT the material, but the care, quality and attention to detail. The material is really not highly relevant if the boat is well built (unless you are trying to build ultra ultra light).

I personally have never liked the way 'standard' cored hulls are made - it is easy to screw up and it is easy later for core shear and water migration - but it is perfectly possible to do it 'more properly' to avoid all these problems.
 
Last edited:
Hello...

I'm having problems replying to this thread. I previously typed up a reply and for some reason that didn't upload to the forum. Forgive me for my summary of that earlier reply, but it's late and I'm a little frustrated.

Thank you very much to everyone who voted or replied. That's useful information/feedback. The bottom line is that the broad perception is that GRP has the edge over aluminium. GRP is favoured for coastal cruising and aluminium has the edge for more challenging environments. It's perhaps worth pointing out this is possibly more about perception rather than solely the hard facts.

The votes as they stand from a total of 45 cast are:

33 for GRP (73%)

12 for Aluminium (26%)

Thanks very much once again and Happy New Year to each and every one of you.
 
> GRP is favoured for coastal cruising and aluminium has the edge for more challenging environments. It's perhaps worth pointing out this is possibly more about perception rather than solely the hard facts.


Not perception, as I said a survey of boats passing through NZ said the majority are metal, it also said that 90% of metal boats that hit a reef get off and 90% of GRP boats don't.
 
It would be interesting to see same question asked in a French forum, almost all of the boats under 10 years old that we see in Brittany are Aluminium. I've been converted to the material over the last few years, although my wife calls them "tin boats".
 
I think a lot depends if you plan to crunch through ice or not, or bounce off a lot of coral reefs. In both these circumstances alloy is excellent, far better than GRP. But for ordinary cruising GRP with some good modern resins and maybe some carbon/kevlar stiffening is a pretty fantastic material - for overall usability and minimal maintenance.
 
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