What Type of Material for a Boat Build?

[Rollbar]

I have several plans in stock and trying to decide which boat I want to build (16'-18' Flats/Bay Boat).
The plans call for plywood/plywood on frame for some plans, and stitch-n-glue for others.
I can buy other plans if needed or design my own (I think).
I really don't want to use wood.
So what material can I use and glass over, or is there a special procedure I will have to do?
Thanks, new builder, but have the time to work the material into what it needs to be if the coast isn't to high.
JB

 

[Mr Efficiency]

Why the prejudice against wood ? It would make it a lot simpler, and quicker.

 

[Rollbar]

Want to go as lite as I can and least wood possible.

 

[Mr Efficiency]

You can't get much lighter than ply, and it will last OK. Why the prejudice against wood ?

 

[upchurchmr]

The best material to glass over is wood.

The next best material is polyurethane foam (not styrofoam). But it will cost more, but it will float higher in a capsize.

I had a coworker who had a welded aluminum pirogue.
Didn't need glass.
It was strong as a tank.
But it would have sunk just as fast.

What's your problem with wood. (Prejudice is a politically insensitive word now days!)

 

[Mr Efficiency]

(Prejudice is a politically insensitive word now days!)

Don't you just love how virtue-signallers have decided for us, what words can be used, and how.

 

[Rollbar]

Thanks for the replies.
-Not prejudice against wood, just thought there was something I could use to bend/flex easier and lighter than wood and to also reduce weight as much as I can.
-Can I go thinner on the wood's thickness (3/8"-1/4") and double up on the glass, or will that put me right back where I started?

 

[bajansailor]

You could laminate your own fibreglass sheets from (eg) stitchmat, and use these instead of plywood - one advantage of doing this is that everything can be done with polyester resin, whereas with plywood you should ideally use epoxy.

I am not sure though that there would be any weight saving; rather, single skin fibreglass sheets would probably work out to be heavier than plywood for the same stiffness?
Or make the fibreglass sheets a bit lighter, and glass in some foam stiffeners as required on large flat areas?
This could be a '6 of one and a half dozen of the other' idea though re weight saving.

How strong does your Flats Boat have to be? If you want it to happily survive a collision with a floating object at 15 knots then it will have to be pretty strong (and hence heavier).

 

[upchurchmr]

Mr E,

It was a joke - lighten up.

Virtue signaling my ***.

I hate being automatically censored - it seems so impersonal. Give me personal hate and intolerance any time. At least it is honest.

 

[upchurchmr]

Single skin fiberglass will always be heavier than plywood fiberglass.

You need to get the density of wood, fiberglass, and look at some typical thicknesses.
Then calculate weights.
No guessing about it.

You could make strip planked panels coated in fiberglass. Strip planked in the usual thicknesses can be bent to almost any useful curveature.

 

[Rollbar]

Ok thank you all for the help.

 

[bajansailor]

Upchurch noted that "You could make strip planked panels coated in fiberglass. Strip planked in the usual thicknesses can be bent to almost any useful curvature."

For a good example of this, have a look at Dog Cavalry's epic thread about the strip planked Sea Sled that he is building.

Sea Sled madness. It’s in my brain. https://www.boatdesign.net/threads/sea-sled-madness-it%E2%80%99s-in-my-brain.63079/

 

[Rollbar]

Thank you I will.
Appreciate it everyone.

 

[Will Gilmore]

You could look into this:
Lightweight Aluminum Honeycomb Panels For Ship Building Industry

Lightweight Aluminum Honeycomb Panels For Ship Building Industry http://m.aluminumcladdingmaterial.com/sale-11256238-lightweight-aluminum-honeycomb-panels-for-ship-building-industry.html

And be sure to tell us how it worked out. I, for one, am very curious to know.

-Will (Dragonfly)

 

[bajansailor]

Will, I don't think that these panels will bend (even slightly) very easily.
The panels appear to be 3m x 1..5m in size, with thicknesses varying from 10 to 35 mm.
I wonder how easily fibreglass (or epoxy even) will stick to these panels?

However they also mention that the minimum order quantity is 600 square metres - that is more than 6,000 square feet..........