Basic GRP layup

Sonar · 06 February 2010, 07:32

Can any of the forum members help me with this one.

Grp laying up a hull of 18foot. ( home build )

I have been told layup to a 6 oz then fit stiffeners and then lay up another 4 oz .

A total of 10 oz.

another 2 oz along the keel and transom.

Is this strong enough ?
or over the top for an 18 foot rib?

biffer · 06 February 2010, 14:28

Quote:

Originally Posted by Sonar

Can any of the forum members help me with this one.

Grp laying up a hull of 18foot. ( home build )

I have been told layup to a 6 oz then fit stiffeners and then lay up another 4 oz .

A total of 10 oz.

another 2 oz along the keel and transom.

Is this strong enough ?
or over the top for an 18 foot rib?

what are you going to do with all this information you are collecting?

the layup for a small fisher, i reckon something like 2x 600, 1x 800/300 combi, 1x 600 (600 is 2oz)
i would lay 600chop,800/300combi, 600chop over stiffeners
dont worry about the 2oz over the keel as the overlap from each side should come up 300mm either side.
it's a light layup and nowhere near what a rib hull gets, but i'm assuming there's gunnels and things above deck to give it some rigidity
thats a simple answer but it's not quite that easy, you still have fillins for spray rails and chines, transom woods, stringers, floor supports and lots more but as you ask i thought someone should answer

chewy · 06 February 2010, 15:11

For my tender I was going to use 600g CSM then 600g Woven roving then 600g CSM.

Sonar · 06 February 2010, 15:43

Quote:

Originally Posted by biffer

what are you going to do with all this information you are collecting?

the layup for a small fisher, i reckon something like 2x 600, 1x 800/300 combi, 1x 600 (600 is 2oz)
i would lay 600chop,800/300combi, 600chop over stiffeners
dont worry about the 2oz over the keel as the overlap from each side should come up 300mm either side.
it's a light layup and nowhere near what a rib hull gets, but i'm assuming there's gunnels and things above deck to give it some rigidity
thats a simple answer but it's not quite that easy, you still have fillins for spray rails and chines, transom woods, stringers, floor supports and lots more but as you ask i thought someone should answer

I am thinking on a home build rib.
More information gained will decide if i take it to task or not.
Thanks for the reply.

Poly · 06 February 2010, 19:44

Quote:

Originally Posted by Sonar

I am thinking on a home build rib.
More information gained will decide if i take it to task or not.
Thanks for the reply.

A couple of things to bear in mind:

(1) The RCD essentially means that you either have to get it CE marked (relatively expensive for a one off) or not sell it for five years. If it turns out not to do what you need or your circumstances change this might be a PITA.

(2) IMHO - generally speaking - a one off boat especially one with no reputable builder behind it won't be as valuable/hold its value as well as a boat from a recognised brand/builder/designer.

Add to that the costs of tooling up for a single GRP boat and I don't think it will actually be that ecconomical to build a boat from scratch, compared to e.g. buying an osprey/humber/shakespeare bare hull and rigging it / fitting it out yourself. Possibly using your own console, seat pod moulding etc - if you want to do something clever there.

Unless of course you are planning to do something significantly different with the hull design - but it doesn't sound like it from your other posts.

Sonar · 06 February 2010, 19:59

Quote:

Originally Posted by Polwart

A couple of things to bear in mind:

(1) The RCD essentially means that you either have to get it CE marked (relatively expensive for a one off) or not sell it for five years. If it turns out not to do what you need or your circumstances change this might be a PITA.

(2) IMHO - generally speaking - a one off boat especially one with no reputable builder behind it won't be as valuable/hold its value as well as a boat from a recognised brand/builder/designer.

Add to that the costs of tooling up for a single GRP boat and I don't think it will actually be that ecconomical to build a boat from scratch, compared to e.g. buying an osprey/humber/shakespeare bare hull and rigging it / fitting it out yourself. Possibly using your own console, seat pod moulding etc - if you want to do something clever there.

Unless of course you are planning to do something significantly different with the hull design - but it doesn't sound like it from your other posts.

I just want to make a rib to my personal specs as you said not worth a thing to anybody else.

I have a bit of time i would like to spend doing a project.

I was wanting the hull only

Min basic thing. or even a cheap mishap.

I have as yet not decided to build one myself until as you can see have delved into the pros and cons.

But It looks like if you want to build one its better to start with a makers hull.

Still got a few questions I need to ask But looking doubtful now.

Thanks

Robert

Downhilldai · 07 February 2010, 23:41

What are you doing about a mould?

Sonar · 08 February 2010, 06:50

Quote:

Originally Posted by Downhilldai

What are you doing about a mould?

I was going to make a rib from scratch but after receiving advise from the forum I decided not to so i am looking at making a fishing boat now .

well having said that possibly .....

biffer · 08 February 2010, 08:37

go for it! will cost you a fortune but if your having fun, why not, the boys are right though, you could sell it as a prototype and you'll have trouble insuring it but what the hell, we're a long time dead!

Sonar · 09 February 2010, 15:19

Quote:

Originally Posted by Sonar

Can any of the forum members help me with this one.

Grp laying up a hull of 18foot. ( home build )

I have been told layup to a 6 oz then fit stiffeners and then lay up another 4 oz .

A total of 10 oz.

another 2 oz along the keel and transom.

Is this strong enough ?
or over the top for an 18 foot rib?

This is NOT me !!!!
I was looking at something else..
Defending myself here because the questions on the bottom are asked by Robert.

But not this Robert..

http://cgi.ebay.co.uk/ws/eBayISAPI.d...=STRK:MEWNX:IT

Pablo · 10 February 2010, 16:32

You could do your own RIB by buy the parts from these Guys: http://www.ggfboatrepairs.co.uk/page_1818315.html

Downhilldai · 10 February 2010, 17:09

Quote:

Originally Posted by Pablo

You could do your own RIB by buy the parts from these Guys: http://www.ggfboatrepairs.co.uk/page_1818315.html

That looks interesting: a 5.5m Dory rib, rated to 150hp