Need help, First time boat builder

[justinfitz1]

I am trying to build a poling platform, for Floundering, similar to the sites listed below. I would like the craft to be fairly light weight. My question is were to start? what materials should I use?


http://www.texaskayakfisherman.com/f...0927&highlight

[TeddyDiver]

How long life you expect for it, and how much you are willing to invest?
If doing something like that I'd make the core from urethane (foam) isolation boards, and cover with glasfibre (biaxial 200g) with epoxy. Total weight would be around 6-10kg/14-22lbs...

[justinfitz1]

If I can get a couple years out of it would be nice, but if not? A couple hundred bucks is what I wanted to spend. I wanted the deminsions to be 12' long X 40" wide X and 6"-8" Deep. And wanted to keep the weight under 130lbs and need it to hold 600 to 700 lbs if possible. I plan to attach a trolling motor to the stern of the platform, and Rig a light setup for the bow.

[alan white]

I would agree with the last commenter, except I would use polystyrene foam, probably laminated from insulation board to the dimensions mentioned.
I would shape the bow, but otherwise build a simple rectangle thick enough to carry the desired payload at 1/2 submersion.
10 oz fiberglass cloth and epoxy would be adaquate sheathing with some extra overlap at the corners for abrasion resistance.
I would then paint the hull with single part urethane and add non-skid to the deck. The shape would displace a total of 1400 lbs, or about 22 cubic feet.
Seven inches appears to be about the target depth needed.
My guess is that the weight could be calculated based on the specified weight of styrene foam per cubic foot (22) and a calculation of the weight of 10 oz cloth and perhaps one gallon of epoxy (100 sq ft).
Add a piece of 3/4" plywood about 18" x 6" and two gussets to brace it (about 2-3 lbs) and there's your weight.

Alan

[longliner45]

justinfitz,,,ive seen kids in lousianna pull a12 ft jon boat,,the boy walked in the water pulling the boat behind him,,,,,spearing flounders,,,,,,,you dont need to design a boat for this,,,,,,just need to learn about flounders,,,,longliner

[justinfitz1]

longliner, Been Flounder Gigging since I was knee high to a grasshopper, and all I have ever done was walk. Had a lantern in one hand and a gig in the other, but never gigged more than 5 flounder. Having a small skiff with lights and trolling motor will allow me to cover more ground and hopefully gig more fish. Besides I'm tired of walking and gigging, time to gig in style!!!


Alan and Teddy, Thanks for the info! Found a place that has a solid piece of Expanded Polstyrene, here are the dimensions I plan to use 12' x 4' x 7" . They can even shape the bow for me, for a extra cost. Alan I know this might be a stupid question, but what is the (plywood about 18" x 6" and two gussets to brace it) for?

[alan white]

Originally Posted by justinfitz1

longliner, Been Flounder Gigging since I was knee high to a grasshopper, and all I have ever done was walk. Had a lantern in one hand and a gig in the other, but never gigged more than 5 flounder. Having a small skiff with lights and trolling motor will allow me to cover more ground and hopefully gig more fish. Besides I'm tired of walking and gigging, time to gig in style!!!


Alan and Teddy, Thanks for the info! Found a place that has a solid piece of Expanded Polstyrene, here are the dimensions I plan to use 12' x 4' x 7" . They can even shape the bow for me, for a extra cost. Alan I know this might be a stupid question, but what is the (plywood about 18" x 6" and two gussets to brace it) for?

Why that would be the motor mount!

[longliner45]

hey man Im not knoking you ,,,like I said seen kidds do it,,,,,,,put a trollingmotor on a jonboat and go at it,,,,,,good luck ,,,longliner

[justinfitz1]

Thanks guys, this forum and its members have really helped me out. I have one more question. Im trying to keep the cost down on the materials (student sallery) can anyone recomend a good cheap epoxy, and cheap 10 oz cloth? And how much of each should I buy for my project ? Do I need to apply multiple coats? I am new to all of this and am just trying to get a game plan

[TeddyDiver]

Originally Posted by justinfitz1

can anyone recomend a good cheap epoxy, and cheap 10 oz cloth? And how much of each should I buy for my project ? Do I need to apply multiple coats?

Biaxial cloth is best and quite reasonably prized too, although I con't know anything about the prizes round there. If you happen to find someone doing a bigger project you might get the materials in reasonable cost, and if got some time to hang around there some valuable experience too.
Epoxy resin you need about as much as GF cloth in weight.

[erik818]

justinfitz1,
Epoxy is one of the few materials that will not let moisture through. You might get a breach in the epoxy/fibre skin, so check anyway that the expanded polystyrene you use has closed cells that will not absorb water. If it's intended to be used for ground insulation (something that might not be applicable to Texas), it probably is OK. I guess your platform will be out of the water most of the time, so it will last several years regardless of polystyrene foam quality.

Paint the exoxy to protect it from UV, or it will deteriorate rapidly in the sun. White is best as it keeps cooler in the sun, and usually is very good at absorbing UV.

Your problem comes after you have succeeded with this project, and within budget. Wasn't it quite easy to build something that floats?
Your apetite will grow.
Why not build a proper boat? Wouldn't it be nice to have something for cruising the Gulf of Mexico?
Now you have found your purpose in life, and something that can absorb all the money and time you have.

Good luck and get addicted,
Erik

[alan white]

Add enough coats to fill the weave completely, and then a bit more. That means at least three coats of epoxy.
For your type of boat, all the coats should be done "hot", meaning watch the previous coat and when it tacks up, immediately add the following coat. doing so will allow you to skip sanding, which wastes epoxy and is not fun anyhow. But wait too long, and the cured epoxy must be sanded to allow the following coat to adhere properly. With the right hardener, one long day and at least three coats could be applied. Alternately, if you go overnight, use a slow hardener and stretch the process over three days. Slower, but more controllable. It won't need sanding that way either.

Alan

[ted655]

I'd use 1" polystyrene laminated, stagger the joints of each layer. Use "PL" glue. Put a 1/8" luan plywood skin om it, add a skeg Paint it with good acrylic house paint, adding fine sand to the topsides.
I doubt you will escape for $200 though. Jon boats are noisy. Is it a ray or flounder? The next step will tell.
Mmmmmm, I love grilled flounder