How is your boat built?

[burgundyben]

Green Marine in Lymington were vacuum bagging the hulls of the composite (kevlar, glass, epoxy) Mersey class lifeboats for the RNLI in the very early 90's before this patent was issued. The hulls were built in two longitudinal halves on moulds - one half at a time.
In summary, the prepreg cloth (already soaked in epoxy, and kept in the fridge) was laid out in the mould and then a vacuum bag was spread over the whole thing, and all the air sucked out. The hull component was then 'cooked' (at about Gas Mark 1..... ) in a rather large oven.

Vacuum bagging and curing glue in a big oven goes back a lot further than that.

Perhaps not with GRP and FRP but its decades older than the 90's.

http://www.faireyownersclub.co.uk/default.asp?content=archive&photo=2&max=4&min=1

 

[Bajansailor]

Ace photos Ben, tnx for the link!

Sorry, I had forgotten that Fairey Marine used to cook their hulls in the 60's as well.

I am sure that somebody will come along now with definitive proof that Noah hot moulded the Ark, and the world regressed for the next how-ever-many-years until epoxy was invented....

 

[Sultans_Kapitein]

Steel is the way

Steel is the best way to build a boat, not Balsa wood or grp cores or vaccum bagging, good hard steel

Mal

 

[[2068]]

Hmmm. One quality of fibreglass that is quite handy in a marine environment is that it doesn't oxidise on contact with salty water.

Not an issue if you are the grey funnel fleet, and can send a dozen matelots over the guard rail with paint, tho...

 

[MapisM]

Steel is the best way to build a boat

Seconded, particularly if you mean a proper boat.
But here as I understand it's a planing boat the OP is interested in, and that rules out steel (and wood as well, for that matter).
Apropos, with apologies for going OT a bit, how is the restoration of your little ship progressing?

 

[Bajansailor]

Re proper steel planing boats, there is the only steel Arun lifeboat 'Snolda' (no 52-30) that was stationed in the Shetlands, and the three (I think) Thames class vessels, and of course all the 44' Waveneys..... although I suppose these are all probably semi-displacement (or semi-planing) rather than planing hull forms.

I worked for a bit in a wee boatyard here building 27' and 37' fibreglass fishing vessels - we were very proud of the fact that the only timber used in their construction was the wooden rubbing strake. The hulls were single skin everywhere, the engine beds were hollow fibreglass top hat sections (with steel plates glassed in for the mounts), and the bulkheads and decks / cabin tops were all cored with either Nida-core or one of the proprietary brands of foam.
The hull to deck joint was an overlap of the two flanges with 5200 in between and through- bolted every 6" or so (incl the bolts securing the rubbing strake).

 

[burgundyben]

Sorry, I had forgotten that Fairey Marine used to cook their hulls in the 60's as well.

1950's.

(and wood as well, for that matter).

Why not wood for a planing boat?

 

[MapisM]

Why not wood for a planing boat?

Same reason as steel: planing boats efficiency - other things being equal - is inversely proportional to their weight.
It is indeed possible to use both steel (as Bajansailor pointed out) and wood (as a few pleasure boat builders still do) for planing boats, but these materials are inherently more appropriate for full displacement hulls.

 

[Nick_H]

Not a well known boat, but interesting anyway due to its different build process, is the Prinz. I went to the factory in Croatia a few years back.

Virtually every moulding on the boat is vacuum bagged using epoxy, with the hull also strengthened with Kevlar as well as normal glass matt. Even the internal bulkheads are all epoxy vacuum bagged, so it's a much more production line approach than any other European builders I know of. Their claim was that it would be stronger than other 50+ foot sport cruisers, but weigh 30% less. They didn't manage that on the first boats though, as the weight was only marginally less than similar sized boats. Not sure if they got any closer to the claim on later hulls, as I haven't heard much about them since.

 

[BartW]

This might be an interesting photo for this thread.

Mike,
is this your princess ?
on this picture she seems huge

I can see the two hubs for the shafts,
what is the purpose of that hub on the bottom on port side ?
(and there seems to be a similar one on SB side)

 

[MapisM]

P95 and exhausts respectively.
At least, that's what I thought when i saw the pic.

 

[Hurricane]

Yep - 95

I seem to remember that they said that on this one, they release the mould by forcing water in.

 

[Sultans_Kapitein]

Apropos, with apologies for going OT a bit, how is the restoration of your little ship progressing?

Well to be truthful the snail, at which pace it was progressing, has died!
Am waiting to get the engines out and into a workshop, but the yard say 'oh you can't go into the workshop on a Saturday or Sunday' and as I work all week that means I cannot go into the workshops. So they (the boat yard) said they are trying to find me a container to put them in, they are Leyland Six Cylinder Diesel engines (Ex-Bus/Truck) so too big to cart home! Never mind, anything worth having is worth the pain

Mal

 

[MapisM]

Never mind, anything worth having is worth the pain

How true!
All the very best, I really hope you'll be able to show us some pics of the "new" Sultan in full glory, in the near future.

 

[grumpy_o_g]

Same reason as steel: planing boats efficiency - other things being equal - is inversely proportional to their weight.
It is indeed possible to use both steel (as Bajansailor pointed out) and wood (as a few pleasure boat builders still do) for planing boats, but these materials are inherently more appropriate for full displacement hulls.

I'm not sure I'd agree it's weight so much as cost with a wood hull. To build a lightweight planing hull in wood is going to be much more expensive than even Kevlar I agree.

This is what happens when you ask a proper boatbuilder to build a power boat...

http://www.spirityachts.com/spirityachts_p40_ss.htm

 

[Csail]

Why does he want a 45 inch boat anyway???

 

[MapisM]

I'm not sure I'd agree it's weight so much as cost with a wood hull.

Well I guess we should agree upon the meaning of wood construction.
To me, multilayer plywood with phenolic resins (wihch is often used to achieve reasonable weight/strength ratios) isn't "real" wood.
But I see what you mean.

Nice, that Spirit Yachts! But the sterndrives, urgh...?!?
Probably the choice was efficiency driven, but I'd rather sacrifice some performance for a proper look, on a boat like that.
Possibly even considering - heaven forbid - IPS or Zeus, if shafts would be problematic for other reasons.