Trying to figure out how to design Jon boat

[eagle19]

My goal is trying to build a 14ft Jon boat under $400. However, I don't just want a regular jon boat so it's hard to find plans. I want to have a modified-v hull, but I still want it to be flat bottom. I would use it to fish and hunt in rivers and sometimes on lakes, flat bottoms hulls on semi-choppy lakes aren't fun. Most of the plans I have found have horizontal benches to help support the side. Well I don't want horizontal benches because they are a pain to jump over when you're on a boat by yourself. I want to have a bench at the back of the boat by the motor and the front decked out about 3 foot. I also wouldn't want framing on the bottom of the boat because I don't like tripping on them. I'm sure they are much more smaller on wooden boats compared to aluminum frame pieces so it may not be as bad as I think. If some one else comes with me I'll just throw a cooler in the middle vertically for a bench, or maybe build a vertical bench onto it later on. And it's being powered by a 7hp long tail so the lighter the better.

So I have a couple questions:

What is the best way to build the boat, frame it out or stitch and glue?


Since I don't want floor supports sticking up is there a different way to support the sides of the boat or should the front decking of the boat and back bench be enough to support the sides?

Anybody seen any plans similar to what I described? I saw 15ft Garvey plans that look kinda like what I want but I want one thats 14ft and it's cost of build was estimated at $1200 and it wasn't a flat bottom.

 

[gonzo]

You can make the bottom thicker and have outside longitudinal strips to stiffen the bottom.

 

[ThomD]

If you stitch and glue it, which would be worth it to me, then doing it for 400 might be a problem. I'm in Canada, so my prices are higher, but you have to really watch the pennies to hit that number. Depends what stuff you can get cheaply. For instance 2 sheets of ply, and you might need part of 3, is like 250-300, and you haven't bought anything else. Of course there are products one can substitute for a lot less, but then that comes down to what you know about materials, and what you can find. Locally I can get a good panel for 15 bucks in 1/4, but 3/8 is a lot more expensive. It just depends what local yards have, since they aren't buying it for boats at that price, they can decide to get something new for underlayment, save a buck, and there goes one's source for a material, for ever.

Some of the advantages to S&G is that the product will last several lifetimes, and it is far better at structuring the clean interior you seem to want.

 

[nimblemotors]

You would essentially just use a flat sheet over the stringers to give you the smooth bottom. It would increase the weight and is more work than required, but if that is what you want. This photo shows overkill for a calm water boat, but gives the idea. Much easier to do for a flat bottom boat.
You are essentially creating a kind of honeycomb flat panel.
Just make sure all water can drain out!

 

[eagle19]

Thanks Nimblemotors, Thats kinda what I was thinking might have to happen.

After Gonzo's post I got to thinking, what if I get 2x4's (which I can get free scraps from my job) and put them inside the starboard and port side walls vertically? They would help brace the sides and I could screw the bottom plywood to those 2x4's. I would think with the transom and a bench holding the sides together in the back and the deck holding the front sides together the 2x4's in the middle should hold?

Honestly I would think stitch and glue might end up being cheaper for me? I would want to fiberglass the bottom of the boat at least so I will have to buy resin already.

Would a plywood from a lumber yard work best? I'm not looking for something to last forever, just something for me to last through college.

 

[messabout]

You want a vee hull but you want it to be flat bottomed. You can not have it both ways.

Do you mean that you want a vee bow that will transition to flat? A fourteen foot boat is fussy about the way that you distribute the weights. Unless you are an unusually lightweight person, the boat may not like you to sit near the transom.

 

[eagle19]

Google modified-v jon boat. It's a real shallow v hull, it more or less just breaks waves and helps on a little bit more on choppy water but it is still very flat.

 

[rwatson]

Google modified-v jon boat. It's a real shallow v hull, it more or less just breaks waves and helps on a little bit more on choppy water but it is still very flat.

So, not flat bottom. A very small V wont break waves much, and is hardly worth all the extra bother for a novice builder.

Using inferior materials is the best way to build cheaper - it just wont last as long. Well painted exterior ply will last a while.

If you can get free 2 x 4's, you will need to be able to saw and plane them thinner if you dont want a boat that is too heavy to carry or transport comfortably.

Its possible to build a whole boat out of 2 x 4's but it would take 4 men to lift it.

 

[Village_Idiot]

I built a wooden jon boat (garvey style) in high school shop class, with no plans. It was only eight feet long and maybe 42 inches wide. I think I used 3/8" marine plywood for the bottom, and yellow pine 1x12's for the sides, bow and transom. I used 2x2's on 12" for transverse stringers. Screwed it all together with 3" galvanized screws, added a few handles and oarlocks, epoxied all of the joints and screw heads, then topped it all off with some forest green paint and marine spar varnish. Used it on local lakes and small rivers (just paddling) for a few years, then it sat in the farmyard for another 20 years, mostly used to cover a well, then my brother scabbed it to make a trough for feeding his hogs. Held up for a couple more years before the hogs finally busted it up. Paint still looked good, no signs of rot anywhere. Total cost for building the boat was around $120, but that was back in the early 1980s.

I've seen longitudinal stringers on current custom aluminum builds; would reduce tripping hazards - don't know how that would translate over to wood, though. You might also consider something as simple as bookshelf brackets to tie the sides to the sole.

 

[eagle19]

Ok after doing a little research I found a buddy with a modified V- aluminum jon boat. He said it's got a 3 degree v but he has a 35 horse motor on it. I have a 7hp long tail motor, I just got a bigger prop and haven't tried it on the 16ft boat it's on now. So I'm not sure if it will plane out or not, with my 6.25inch prop it would some times but now in have a 7.5 inch prop on there. I plan on modding the engine to hopefully get 9-10hp later on too.

With all that said, with a 10 horse motor and a 3 degree v would I see much of a difference compared to a flat bottom? Would I plane out any easier or handle waves any easier at all?

I don't think it would make a difference in the rivers due to the fact of currents and I have to go so slow half the time anyways because of fallen trees and what not. But I don't know too much about lakes which I would like to get more into.

 

[nimblemotors]

It is a lot more complicated to build, but a catamaran would handle chop much better than a shallow vee. See for example, the livingston boats, this 12footer,

http://www.livingstonboats.com/pages/livingston-12-boat

 

[eagle19]

I just wonder how well a catamaran would handle in the river, how much more complicated it is to build, and if it needs to be wider than 4ft.

 

[messabout]

Three degrees of deadrise is not even worth considering if intended for mitigation of pounding. A three degree vee on a 48 inch bottom would raise the chine only about 1.25 inches. Not worth the trouble. Such a bottom will not plane better or sooner.

There are structural advantages with deeper vees. The panel is put partially in compression and diminished in bending load. A tiny 3 degree vee will not change that by enough to matter. A 25 degree vee would matter but of course your draft would increase if the vee continued toward the transom. A deep vee will also require considerably more power to get on a plane.

 

[DCockey]

.....

There are structural advantages with deeper vees. The panel is put partially in compression and diminished in bending load. A tiny 3 degree vee will not change that by enough to matter. A 25 degree vee would matter but of course your draft would increase if the vee continued toward the transom. A deep vee will also require considerably more power to get on a plane.

How is the bottom panel of a deep vee hull put partially in compression and diminished in bending load?

 

[Petros]

it seems to me $400 would be tough to meet unless you just go plywood over frames and stringers, without fiberglass. Just use 7 to 8 coats of quality extierior gloss house paint. The problem is it will require more maintaince and should be stored out of the water and out of the weather when not using it, or it will not hold up very well.

You can get by without any ribs to give you a flat floor and more volumn by making the keel, chine logs and gunwales larger and stiffer, and perhaps use the next size thicker for the floor. You will need at least one or two thwarts to hold the shape. All this would add some weight of course, so there is compromise to getting smooth surfaces inside the hull.

Another approach, but much more work, is to use smaller ribs closer together and than put a floor over them. Though you still loose some inside volume, this can usually be built much lighter.

You can use carefully selected lumber yard sawn lumber and even construction scraps and discards by remilling the lumber on a table saw, selecting around the run-out, knots, sap pockets and other defects, so your final pieces are fairly clear and straight grained wood. I have built 18 small boats mostly from salvaged lumber or lumber yard stock, carefully selecting the wood, or re-milling it to cut out the defects. I have built kayaks and small sailboat for $100-200 by salvaging all of the materials. Perhaps not a durable as a marine plywood and epoxy/fibergalss dingy with Dacron sails, but we got many years of happy service out them at very little cost.