GRP NB

[W+T]

Hi all, to continue from another thread about self build

 

Has anyone built there own boat on a large scale, say above 30`, how did you do this, with a mold or layed upon a polyuarthane shell/frame, which is my idea.

 

Form a shell from poly sheets (kingspan), shape it to how you want, obviously with braces inside etc, then lay up on that, in this way you get a fully insulated boat.

For strength stainless steal floor braces etc.

 

I have worked out that in materials i could build a 45` for around £2500, not bad towards steel at over £6000, yes a lot messyer but you cant have everything.

I know i will get some `dont do it etc etc` `why` but i just like to try and do something different if at all possible.

 

My head is always full of ideas, i prefer to build than buy already done.

 

Go on give me your thoughts.

 

wayne

[Madmark62]

Hi all, to continue from another thread about self build

 

Has anyone built there own boat on a large scale, say above 30`, how did you do this, with a mold or layed upon a polyuarthane shell/frame, which is my idea.

 

Form a shell from poly sheets (kingspan), shape it to how you want, obviously with braces inside etc, then lay up on that, in this way you get a fully insulated boat.

For strength stainless steal floor braces etc.

 

I have worked out that in materials i could build a 45` for around £2500, not bad towards steel at over £6000, yes a lot messyer but you cant have everything.

I know i will get some `dont do it etc etc` `why` but i just like to try and do something different if at all possible.

 

My head is always full of ideas, i prefer to build than buy already done.

 

Go on give me your thoughts.

 

wayne

 

I have no experience in building any boats, but I say go for it mate.

I think you will get a lot of satisfaction in building your own boat and if you have the skills required , then why not just do it!

[soldthehouse]

Go for it Wayne....

 

 

 

 

 

Stuart

[W+T]

thanks guys, would be great to do it, some acheivment and what a buzz. even had a thought of making a BIG one in a 40` garden, the boat being 50` ish, ????????? i hear you say.

 

Well i build a stainless superstructure of about 2" box for the center of the boat, build it in 2 halfs and move each half as when to a yard to bolt together to finish of, a lot more to it but you get the jist...i hope.

 

yep i am puddled, but i love it, and anything is possible if you know how.......do i? LOL

[carlt]

I can't really help you with grp oat construction as my experience is with wood, but I can recommend a book: "The Elements of Boat Strength" bt Dave Gerr, which goes into great detail about Scantlings, Design Considerations and construction methods in GRP, Wood, Aluminium and Steel.

 

It delves deep into the science of designing a nd building a boat and is quite a heavy read but I thought it well worth the effort.

[W+T]

I can't really help you with grp oat construction as my experience is with wood, but I can recommend a book: "The Elements of Boat Strength" bt Dave Gerr, which goes into great detail about Scantlings, Design Considerations and construction methods in GRP, Wood, Aluminium and Steel.

 

It delves deep into the science of designing a nd building a boat and is quite a heavy read but I thought it well worth the effort.

 

 

Forgot to say it will be a NB or wde beam, i lot have been saying to forget it as thought it was a sea going vessel.

 

I will search out the book carl , thanks for that.

Granted it wont be easy but then nothing is thats worth it is easy.

 

 

wayne

[jez1954]

I have worked out that in materials i could build a 45` for around £2500, not bad towards steel at over £6000, yes a lot messyer but you cant have everything.

I know i will get some `dont do it etc etc` `why` but i just like to try and do something different if at all possible.

 

wayne

 

JFDI!! What have you got to lose? It sounds like you'll get hours of fun out of it and if it doesn't work out you've only lost £2,500 - there are a lot more hobbies that cost more than that (I know, I go diving AND have a boat!).

 

Jez

[Teadaemon]

I can't really help you with grp oat construction as my experience is with wood, but I can recommend a book: "The Elements of Boat Strength" bt Dave Gerr, which goes into great detail about Scantlings, Design Considerations and construction methods in GRP, Wood, Aluminium and Steel.

 

It delves deep into the science of designing a nd building a boat and is quite a heavy read but I thought it well worth the effort.

 

I'll second that recommendation, and add that 'The Nature of Boats' by the same author is also worth looking into, as a very accessible introduction to some of the more important aspects of naval architecture.

 

Constructing a one-off GRP boat by glassing over a foam core is a recognised technique, albeit not one that's used very often. The bit that gets very time-consuming is all of the sanding and fairing required to give an acceptable finish to the outside.

 

Building a narrowboat using this method of construction is certainly possible, but such a creation would definitely need a lot of thought at the design stage, and I would question the durability of PU-cored GRP in a canal environment.

 

As a final point, how have you managed to cost the materials for the hull without a detailed design (detailed enough to include a layup schedule, size and number of structural bulkheads, size and number of internal stiffeners, etc)? Does that price include materials for the plug you're going to mould the hull around, or all of the PPE, brushes, rollers, acetone for washing up, etc? Personally, I'd suggest that £2,500 for a 30' narrowboat hull is a very optimistic price, and that £5-10,000 might be more accurate.

[buccaneer]

Looking for something else I came across this

 

http://www.youtube.com/watch?v=dEhSaFfaSKg...feature=related

 

It took just over 5mins

[W+T]

I have tryed to edit my first post in this topic but it will not let me.

 

The price i have given is for just the matting and resin plus some tools, not all equipment, but foam sheets and ply i can get at a very good price., i am doing a costing at the moment to see what it will realy cost, buthten you neevr go of a costing as we all know they always go over budget. So money aside for know, it the build whats more important.

 

I asked a similar question about doing one out of steel, now most of the suggestion were to get a navale architect to set out plans, but it hasnt been suggested with GRP????

A lot of folk said which i believe is true for a NB or wide beam is that in all sense its a skip on water, so why need an architect. but thats on steel.

If was to use same floor bearers etc etc as with steel i cant see why it would be much different, it cant be rocket science to build a boat with a few bulkheads ionplace, made from 3/4 ply and laminated inplace.

If costs are ok with me i will give it a go i think, just wanted to see if anyone had done similar, leave it with me and i will research more and see how to go about it.

 

Thanks folks for the replys

wayne

[Teadaemon]

I have tryed to edit my first post in this topic but it will not let me.

 

The price i have given is for just the matting and resin plus some tools, not all equipment, but foam sheets and ply i can get at a very good price., i am doing a costing at the moment to see what it will realy cost, buthten you neevr go of a costing as we all know they always go over budget. So money aside for know, it the build whats more important.

 

I asked a similar question about doing one out of steel, now most of the suggestion were to get a navale architect to set out plans, but it hasnt been suggested with GRP????

A lot of folk said which i believe is true for a NB or wide beam is that in all sense its a skip on water, so why need an architect. but thats on steel.

If was to use same floor bearers etc etc as with steel i cant see why it would be much different, it cant be rocket science to build a boat with a few bulkheads ionplace, made from 3/4 ply and laminated inplace.

If costs are ok with me i will give it a go i think, just wanted to see if anyone had done similar, leave it with me and i will research more and see how to go about it.

 

Thanks folks for the replys

wayne

 

I did wonder whether to mention the services of a naval architect, but to be quite honest I can't see many naval architects who'd want to spend time on such a design, at least not without a considerable fee (as they're unlikely ever to sell the plans to anybody else). In the absence of a naval architect, I'd still recommend that you draw up a detailed set of plans, and do all the necessary calculations to determine adequate scantlings, displacement, etc.

 

Basically, you have two choices, whatever material you build a boat from:

 

1) Do the maths (or pay somebody to do it for you) and have a reasonable expectation that if built as designed your boat will be usable and work correctly.

 

2) Guess and hope for the best.

 

Copying an existing vessel will be difficult if not impossible, as I don't know of any similar vessels that have been built, and PU foam cored GRP has such radically different characteristics to steel that copying a steel narrowboat is definitely not a sane or sensible option.

 

The more I think about it, the less happy I am at the idea of a foam-cored GRP narrowboat, even one 30' long. Whilst it is technically possible to build such a boat, I cannot think of any reason why one would choose to do so - it's more difficult, has a very large potential for serious problems (widespread delamination and disintegration of the foam core, that sort of thing), and once you've costed up everything, it isn't going to be cheap.

 

If you want to build a 30' narrowboat then realistically your choices are steel or wood (including several variations of wood/glass/epoxy composite), check out http://www.selway-fisher.com/Mcover30.htm for several designs that might be suitable (possibly with some minor alterations - consult with the designer). I do like the Steel Canal Tug with a centre cockpit, and the Hawfinch design for ply on frame is probably fairly close to how I'd construct a wooden narrowboat. There are other designs available, Paul Fisher's site was just the first one I thought of. As you'll see, he does sell study plans, so you can have a good look at what you're getting for your money.

[RLWP]

Cross winding it entering a lock could be interesting. Tawny Owl's hull is quite bent in on the front ten feet of cabin section where years of inexperienced crews have been caught out by by-washes. Her hull bent. What would a GRP one do?

 

Richard

[W+T]

I did wonder whether to mention the services of a naval architect, but to be quite honest I can't see many naval architects who'd want to spend time on such a design, at least not without a considerable fee (as they're unlikely ever to sell the plans to anybody else). In the absence of a naval architect, I'd still recommend that you draw up a detailed set of plans, and do all the necessary calculations to determine adequate scantlings, displacement, etc.

 

Basically, you have two choices, whatever material you build a boat from:

 

1) Do the maths (or pay somebody to do it for you) and have a reasonable expectation that if built as designed your boat will be usable and work correctly.

 

2) Guess and hope for the best.

 

Copying an existing vessel will be difficult if not impossible, as I don't know of any similar vessels that have been built, and PU foam cored GRP has such radically different characteristics to steel that copying a steel narrowboat is definitely not a sane or sensible option.

 

The more I think about it, the less happy I am at the idea of a foam-cored GRP narrowboat, even one 30' long. Whilst it is technically possible to build such a boat, I cannot think of any reason why one would choose to do so - it's more difficult, has a very large potential for serious problems (widespread delamination and disintegration of the foam core, that sort of thing), and once you've costed up everything, it isn't going to be cheap.

 

If you want to build a 30' narrowboat then realistically your choices are steel or wood (including several variations of wood/glass/epoxy composite), check out http://www.selway-fisher.com/Mcover30.htm for several designs that might be suitable (possibly with some minor alterations - consult with the designer). I do like the Steel Canal Tug with a centre cockpit, and the Hawfinch design for ply on frame is probably fairly close to how I'd construct a wooden narrowboat. There are other designs available, Paul Fisher's site was just the first one I thought of. As you'll see, he does sell study plans, so you can have a good look at what you're getting for your money.

 

 

So it sounds like you think it will work with a foam inner, all depends how long it will take to disintergrate, i will see what they use on other craft of the same construction, i know the Burland boats are construted this way and are a good 30 year old boat, and a lot still going strong.

If foam is no good then why not ply with GRP, another choice.

 

I have looked at plans, all kinds but its the idea of builing your own design, its a one off very personal thing to those who like to design and build something, not just boats, i have have built many cars and the satisfaction when finished and used is a whole lot more from going into a show room and saying ill take that one or build me this or that.

 

As for durability on the canal for a GRP NB, there is loads of large GRP on the system, IMO its down to the person in control of the vessel if its going to stay in one piece. The first boat i got ended up with a six inch hole in the bow by hitting locks as it was the first time i had even been ij control of a proper boat, after a while not a problem, yes a few scrapes but thats boating.

 

 

From what it seams not many have gone down this route, if anyone, now this doesnt mean its not possible or safe or whatever, just that most like the easy way and use steel, there is a company tha makes GRP narrow boats, i just cant remmeber who they are.

 

Anyway its an idea as said, if i was to do this then i would just gather as much info as possible on building a flat bottomed GRP craft, where to place bearers etc and just do it, costing allowing.

 

 

wayne

[David Schweizer]

Hi all, to continue from another thread about self build

 

Has anyone built there own boat on a large scale, say above 30`, how did you do this, with a mold or layed upon a polyuarthane shell/frame, which is my idea.

 

Form a shell from poly sheets (kingspan), shape it to how you want, obviously with braces inside etc, then lay up on that, in this way you get a fully insulated boat.

For strength stainless steal floor braces etc.

 

I have worked out that in materials i could build a 45` for around £2500, not bad towards steel at over £6000, yes a lot messyer but you cant have everything.

I know i will get some `dont do it etc etc` `why` but i just like to try and do something different if at all possible.

 

My head is always full of ideas, i prefer to build than buy already done.

 

Go on give me your thoughts.

 

wayne

I have helped to build several smaller boats from fibreglass, but we always either used a fibreglass mould which had been taken from another boat, or built a timber mould and varnished it to a very high gloss finish.

 

How are you going to maintain the shape whilst the resin soaked glass is curing? it goes very floppy and I cannot see how you will manage to prevent a very distorted shape without using a reinforced mould.

 

If you try and lay glass fibre and resin onto an internal mould, you are going to have a lot of work afterwards sanding down to get a smooth surface. I have only done this once on two small panels, it took ages, and to be honest has never looked that good.

Edited February 25, 2010 by David Schweizer