Adding stability to a skinny boat using pontoons

[KillerBeeZ]

I have a 14 foot Jon boat with a 48in beam. I would like to add a deck, but I'm well aware of the stability issues with such a skinny boat.

So I had an idea I'd like to run by you experts.

What if I added pontoons to the side that retract up for transport? I realize it will slow the boat down... that is ok, I'm a fisherman not a racer lol

I drew a sketch, please forgive my horrid artistry, I'm much better with a pole than a pen... thoughts?

 

[Silvertip]

I'd be looking for a different boat. The cost to add pontoons would likely make up the difference between selling yours and the replacement.

 

[KillerBeeZ]

I could build my own pontoons... I'm pretty handy and have all sorts of tools and materials

 

[Grub54891]

I'd think attaching them would put a lot of stress on the gunnels. They aren't designed for that.

 

[Silver Eagle]

Why not just get a used bass boat.?

 

[KillerBeeZ]

my issue with getting another boat in general is money lol... as in I have a 6 year old ergo I have very little of it lol

Only reason I got this boat was because the guy owed me money

 

[KillerBeeZ]

I'd think attaching them would put a lot of stress on the gunnels. They aren't designed for that.

What if I attached them to the bench in the middle?

 

[HotTommy]

KillerBeez,
My opinion is that your idea is theoretically possible, but I doubt you'd be lucky enough to get everything right on the first attempt. By the time you do several trial and error mods, you might have more money in it than you'd want. My training is as an aerospace engineer rather than boat designer, but I know enough to predict a few of the major challenges you'll face.

1. It's unlikely you'll be able to attach an outrigger (pontoon on an arm) to the thin aluminum on the side of the boat without the aluminum failing. The configuration most likely to work would be one or more arms that run the full length from outrigger to outrigger. The arm(s) would attach to the sides, tops and seats of the boat to spread the load on the aluminum.
2. The pontoons will have to sit deep enough in the water to provide stability even before you place a load out toward the edge of your deck. Otherwise they will not resist the boat rocking until they are pushed down into the water by a load. But if you place them too deep, the arms will be supporting some of the weight of the boat all the time, putting stress on the arms and the boat where the arms are attached.
3. The amount of lift you will need from the pontoons can be calculated by the formula: Pontoon lift = W * d / ARM, where W is the weight of the load you are going to have away from the center of the boat, d is the distance that load is from the center of the boat, and ARM is the distance from the center of the boat to the center of the pontoon. For example, if your deck is to support a 200 pound man standing two feet from the center of the boat, a pontoon on a five foot long arm would need to displace (200*2/5) = 80 pounds of water. As water weighs about 62 pounds per cubic foot, your pontoons would need to displace almost 1.5 cubic feet of water at rest.
4. Your pontoons need to be water tight.
5. If you are going to have to assemble and disassemble this contraption every time you use it, you will likely tire of using it unless it is very easy to do.

Good luck in whatever you decide to do.

 

[Scott Danforth]

I would learn to flip lures while sitting. Or.... Sell the boat, convert it to cash, add a small bit of cash to the pile, convert slightly larger cash pile to a slightly larger boat.

 

[ahicks]

You could tie a piece of 8' PVC tubing to each side, then lash a beach ball or some other inflatable toy to the ends of the PVC tube. Substantially more stable at minimum cost, little extra weight. Anything more serious than that, and I'm of the opinion you might want to replace the boat as well.

 

[Reel Kahuna]

Ebay list "Canoe Outriggers" for less than $250. Check them out.

http://i.ebayimg.com/00/s/NDgwWDY0MA==/z/IcwAAOxyUI1TI2mq/$_12.JPG

 

[1983 ercoa 21']

If this is truly what you want to do it's pretty simple find water main PVC pipe think it's 10" cut to length possibly 4 to 6 foot the make end caps to seal the ends. Find the material that will spam the desired width use big hose clamps to attach the tubes to your Frame and use a clamping method to attach to the boat.

 

[1983 ercoa 21']

The frame that holds the tubs should span from tube to tube across the boat .

 

[lmuss53]

With that 10 inch PVC pipe you can drill through the top and bolt it to the crossmember instead of using clamps. Use something like aluminum C channel or square tube for the crossmember. Bolt it down through your middle seat and see how it works.

I think you'll prove to yourself that it isn't real helpful or practical, but it can be done.

 

[airshot]

Yep.....they are already out there but not aluminum pontoons. Most are made from a blow molded plastic or are an inflatable device. Made for canoes and kayaks.
A number of mfgs have them, if you are handy I am sure you could adapt or even copy their ideas. A friend has them on a kayak and can stand up while fishing in his. Now I wouldn't try that but he does..

 

[Silvertip]

Then there is the issue of transportation to and from the body of water you intend to splash this boat. Remove and install the outriggers each trip? Some things just seem like good ideas but in the end make more work than they are worth.

 

[1983 ercoa 21']

Then there is the issue of transportation to and from the body of water you intend to splash this boat. Remove and install the outriggers each trip? Some things just seem like good ideas but in the end make more work than they are worth.

The fun of it is to see if you can build it!
If built with the proper material it can be as easy as pulling a pen and retracting them in or out !