cold moulding vs fiber glass

[nautical]

hi everyone,

What are the advantages of coulding over fiber glass construction for say a 30 m vessel.

All your valued ideas, links and anykind of documents will be appriciated,

Thank you

[PAR]

Both will be heavier then other construction methods, in a vessel that size.

[nautical]

well that didnt help much, but thanks for the reply

[PAR]

All construction methods have advantages and disadvantages. No particular method is more valid than another, without some sort of qualifier. Is there something specific you'd like to know?

[nautical]

ok let me change the question. say I want more knowlage about the method. and i only have access to 20 years old books. and i am sure most glues epoxies have changed.

[Raggi_Thor]

For a 30m vessel global stiffness becomes more important than in smaller vessels at say 10m. For longitudinal stiffness you may want to read about strip-planking, but steel or aluminium is more common choices for this size.

To get answers here it's better to be more specific, and also try the search button first :-9

[PAR]

Cold molding still relies on the same principles, it did 20 years ago. 'Glass boats have experienced changes in the resin used by some manufactures, but the principles are the same. I know of a 130' cold molded hull and a 120' strip planked hull, both turned out to be fine examples of their type, but equally could have been lighter and less costly in metal. Dave Geer's book "Elements of Boat Strength" can bring you up to speed on some of these methods, as well as the technical details of sizing the individual pieces, that make up the vessel. There are several good books on both subjects. Try a search in the BoatDesign.net book store or your favorite book seller.

[nautical]

Thanks again PAR i will sure find that book very soon. I checked our library and I didnt find the book or found some books on plywood boat building. Sure I will get that book oneday.
And Raggi I cant be very specific be becuse I am just starting this. But to be more specific I am more curious about the sheathing. (fiberglass covering) If i am right.

[Raggi_Thor]

OK,
I think PAR is right, over a certain size metal will be lighter (and cheaper) than glass or wood.

[PAR]

I'm not trying to be coy Nautical. It's a complicated subject, covering several engineering disciplines. This isn't the best format to gain a reasonable understanding of the concepts, principles and engineering fundamentals on the topics you desire.

In other words, I could offer a several thousand word explanation on the subject and you'd still have questions.

If interested in books, try http://www.addall.com/, which is All Book Search. Type in the subject you want and you'll find many hits. I typed in the word "fiberglass" and got 17 books.

[nautical]

Thanks par. you have been very helpful. I have collected a few books and got the dave gerrs book too. very nicely explained.

[frosh]

Nautical, with all due respect, I don't think it is at all wise to be considering building a 30m vessel, and asking Forum Members for opinions on the best construction method. Really! 30 meters long and you are not consulting with a top Naval Architect about this vital detail. You have got to be joking!

[nautical]

frosh. you are wrong I am not asking anyone for the best construction method. I asked for some pro and cons. and asked for some sources. And there are top naval architects here ? this forum is not all about amature boat builders and some of them can be really helpful. (btw I have talked to Naval Architects abt this)

[Raggi_Thor]

Nautical, do you have a name?
I agree with you, we discuss everything, just out of curiosity.
If you are going to build a 30 meter boat there are a lot of other questions also, like time and money :-)

[nautical]

Raggi Thor I am very aware of those things. I am not building anything yet or maybe not anytime soon. I am learning