Fibreglass hull layup questions.

[conlan]

Hi all.

I have a question regarding a project that I have started.

Firstly, I am new to these boards. so I will introduce myself. I am a keen bass fisherman, and have wanted to build my own boat for many years as a project. I have no experience with glasing, and am primarily looking to develop a new skill that I can use with my hands, and not head. I work in communications with my focus as a Cisco router technician.

I am prepared to make, and expect to make many mistakes travelling down this path, but I will eventually be fishing with a boat that I have built from the ground up in the next few years.

Anyway, enough about me.

I would like to layup my own 13 foot by 5.5 foot semi deep vee hull. It will be decked out as a bass boat, and be running a 60HP outboard motor [109kg].

The critical factor for me will be weight, being such a small boat.

My fibreglass layout for the first hull is planned as follows:

Layer 1: Iso gelcoat

Layer 2: Iso gelcoat layer 2

Layer 3: Tissue glass layer to prevent print through of the glass pattern to the gelcoat

Layer 4: 300g/meter chopped strand matting [ISO resin]

Layer 5: 350g/meter woven roving, orientation from stem to stern [ISO resin]

Layer 6: 300g/meter chopped strand matting [ISO resin]

Layer 7: 350g/meter woven roving, orientation from stem to stern [ISO resin]

Final layer: 300g/meter chopped strand matting [ISO resin]

I am looking for any advice comments on my layup proposal. Of critical importance to me will be the weight of the hull, it being so small.

Will the above layout be strong enough to handle 60Hp of outboard motor?

Am I making any serious mistakes here?

Thanks for any input in advance.

Conlan

[tunnels]

I have a old 14ft powerboat with less glass and i have a 115 hp V4 yamaha on the back !! does that answer you question about the lay up you have !!

[conlan]

Sounds like I have a little over engineering on my hands here.

I have subsequently discovered something called the "scantling" number, and found some excellent litrature on glass by just reading through these boards.

The Marine Composites pdf looks very interesting, and I will read through that.

By the sound of things though, if I get my stringers correct, I can drop a layer of woven roving and chopped strand matting without endangering the hull integrity?

Once again, thanks for any advice in advance.

Conlan

[tunnels]

This is a lay up for most runabouts 12 foot to 16ft
Gelcoat
300 gram csm
450 gram csm
820 gram woven roving
450 gram csm

Thats about what we use on boats that size ! plus there were bits inside the boat that were glassed in that added to that. The boat i have now has a glass grid and that really makes a differance to the stiffness ,

The only thing i would add to that lay up now would be a Unidirectionall layer on the inside after the
820 gram woven roving
300gram csm
400 gram uni
300 gram csm

The uni need to run 90 degrees to the keel out to the chine and 50mm up the top sides , overlap all the layers of glass 100 mm in the keel line from stem to stern . By doubling layers it then forms a keel inside and thats really nessasary when sitting on a trailer .I also do all the overlaps in the chine as well this is a place that gets dinged a lot and the more layers the stiffer and stronger the hull side .