Wood - lighter, stronger and more durable than grp?

[Deleted User YDKXO]

Interesting video here on the cold moulded wood construction technique used to build Vicem boats in Turkey

http://www.boattest.com/boats/boat_video.aspx?ID=2473

Does the panel agree that their statement that wooden built hulls are 'lighter, stronger and more durable' than grp is correct? I'm assuming that boats manufactured using this technique are generally more expensive than grp so it is understandable that production boat builders went over to grp many years ago but why are there not more manufacturers at the top end of the market using this technique if it has so many advantages?

 

[DAKA]

Any one who has owned a wooden boat knows why they are not for 99% of leisure users.

The maintenance is horrendous.

Really need to store it 5 months over winter in a heated hanger with a team of painters and have a short working life.

Regardless of my perception being accurate today (my wooden boats were years ago and old when I bought them) but my perception is common hence builders cant sell them.

 

[gjgm]

I thought the main advantage in production terms of grp is that once you have made a mould, you can churn out identical hulls/fittings, and its alot quicker= cheaper.

 

[Tranona]

Cold moulded boats should not be confused with "wooden boats" in general. They are in fact composites in a similar fashion to GRP boats except that wood is used instead of glass and foam as the strenghtening core. Properly done there is no reason why they should not last as well as glass reinforced boats. There are also many variations on the broad technique with their own individual characteristics. For example there are many Fairey built hot moulded boats around from the 50's and 60's that are as good as the day they were (expensively) built.

The great advantage of wood epoxy composite construction is that you can build one offs with the strength and durability of GRP without a mould, or only a basic framework. This sometimes works against the builder because it encourages people to have odd designs built which can give the techniques an undeserved reputation.

Generally there are few problems with hulls because they are completely sealed in epoxy. The weakness as with any fabricated structure is with the superstructure where it is difficult to seal all the joints and as we know, fresh water can kill wood if it gets in. The solution sometimes is to use GRP for the superstructure, or sheath the whole lot in glass and epoxy. However this is difficult and expensive with complex superstructures.

One of the reasons why this method is popular in Turkey (and other warm countries such as Malaysia) is that it is labour intensive and needs higher ambient temperatures to cure the resins. So less suitable in cold high labour cost countries.

If I had the money (and the patience!) to custom build this would be my preferred method of construction, particularly as it lends itself to my preferred style of boat. One of the leading builders in this medium lives near me and some of his creations are awesome - if you like that kind of thing!

 

[grumpy_o_g]

Totally agree with Tranona except that I would say the strength comes at least as much from the wood laminate structure itself as the sheathing, whereas with foam core the strength for the sheathing and to an extent from the core. In simple terms most cold-moulded boats would be fine without any sheathing until the rot got to them, whereas foam core GRP without the core would lack strength and stiffness I would think.

 

[PowerYachtBlog]

This technique is used on a wide variety of sport fishermans and was pioneered in the USA, first by the likes of Rybovich and Merritt who started sealing the outside with epoxy in the 70s and then by the North Carolina builders.
Cold molding with glass and resin as today started life in the eighties.
Most US cold molded sport fish builds today are indeed covered with glass. They use wood as the inner structure.
The shear strenght of wood is indeed superior to anything there is out their, and most of these sport fishers are built for charter and they do last as much as a GRP boat.
Some names to check for superior magnificent Cold molded builds are Jarrett Bay, American Custom Yachts, Weaver, F & S, and Paul Mann. Google them and u can see some inbuild pictures which do impress u.
Most cold molded builds today are made with the jig method (which makes for better production), and Paul Mann is one of the few who still builds in the traditional frame and plank way.
As for the cold weather I think they have similar temperatures up North in USA so this is not in line with the facts, and then epoxy has a fame of curing even in the worst temperatures.

 

[Tranona]

As for the cold weather I think they have similar temperatures up North in USA so this is not in line with the facts, and then epoxy has a fame of curing even in the worst temperatures.

The big difference is that in cold climates, particularly where there is a big seasonal difference in temperature and humidity you need to have climate control of some sort to ensure proper cure - this is true of polyester as well as epoxy. In semi tropical climate where there is little change in ambient temperatures no heating (or cooling) is required.

The combination of locally available timber, low cost highly skilled labour, low cost premises and benign conditions encourage this method of build. There are of course negatives, particularly in management and logistics, but some stunning custom builds have come out of places such as Turkey, Sri Lanka, Burma, Malaysia etc.

 

[Bassplayer]

Well, my Fairey's hull is as sound today as when she was built in 1975. 9 layers of 1/8" ply = a strong and light hull.
And it doesn't smell of GRP either, just a nice waft of the teak as you board. Lovely. Especially if you have just regained your sense of smell after 20 years as I have!
Oh help I've gone all Gordon Currey now. Off out on the Medway tomorrow for a pleasant 25knot thrash.
Nurse! My medication! Just 2 spoons of linseed oil tonight.......

 

[MapisM]

And it doesn't smell of GRP either, just a nice waft of the teak as you board. Lovely.

Coming to think of it, whilst I can't say to have ever felt so much of a GRP smell with any of my plastic boats, I did often experience an unpleasant sensation of damp environment, particularly after the boats were left closed for some time.
That's something totally unknown to my current carvel planked boat, no matter for how long she sits unattended in the water.