Sailboat Pontoons to Deck Boat Conversion

[tuort]

I have a pair of G Cat pontoons and the three cross members that connect them which when connected they will be 8 feet wide. I am thinking of building a deck on top of them!!! They are 16.5 feet long and they were free. I think I need some additional flotation so am thinking of using my old but good 12 foot flat bottom fishing boat as additional flotation. This would mount between the pontoons and would allow me to mount a 9.9 hp motor I have on the transom of the 12 foot boat. This distance between the pontoons is more than enough to mount the 12 foot boat to the cross members of the pontoons. I also have a 14 foot flat bottom boat that could be used. I intend to float the pontoons with the deck load and see what the center of balance is and where the water line on the pontoons are. With that info I can then calculate how to mount the flat bottom to the cross members so when its in the water the pontoons and the flat bottom will hopefully be at their natural flotation buoyancy. The initial measurements show that the flat bottom boat will be about right for the distance from the cross members of the pontoons to the water. My problem is to reassemble the pontoons to the cross members since I got the catamaran sailboat in a completely dis-assembled condition. The boat is all here but I don't sail and please don't be to hard on me for taking a perfectly good sailboat and turning it into something else. (Maybe the sailboat guys and sail puritans won't read this) I need all the critical comments I can get so lets hear it.

 

[BobGinCO]

Re: Sailboat Pontoons to Deck Boat Conversion

Make sure you put plenty of NASCAR decals on it...

 

[tuort]

Re: Sailboat Pontoons to Deck Boat Conversion

Make sure you put plenty of NASCAR decals on it...

I guess I don't get it. (NASCAR Decals????? Maybe that's a reference to being from the south?? I would like some critical comments as to the feasibility of this design. Its almost all free stuff and since I am almost 75 years old I don't sail and don't intend to learn how. I thought this would be a neat project to try. I haven't received any post on this idea except yours and apparently there is no interest in it so that in itself tells me to think this over pretty good before I start.

 

[Water logged]

Re: Sailboat Pontoons to Deck Boat Conversion

Ok let me try here. If the pontoons are coming from the cat I'm thinking of you will definitly need additional floatation in order to have a reasonable load capacity. If you use the jon boat idea you will either need to enclose and seal the top of the boat, or have a really heavy duty bilge pump system. Otherwise the jon boat will usually be full of water and tend to drag those little pontoons under. I don't even want to think about what would happen if you were on a waterway that was patrolled and they saw you running that.

Glenn

 

[IslandManMitch]

Re: Sailboat Pontoons to Deck Boat Conversion

I don't think it is a crazy idea. But then again I have thought about mounting a mast and sail on my pontoon boat.

 

[BobGinCO]

Re: Sailboat Pontoons to Deck Boat Conversion

I guess I don't get it. (NASCAR Decals????? ... Its almost all free stuff and since I am almost 75 years old I don't sail and don't intend to learn how.

OK, sorry to put it that way. I think this is a really bad idea, and critically unsafe at best. Heck, I didn't even know you were from the south, but the saying "Hey Bubba, hold my beer and watch this!" DID pop into my head. Strapping a jon boat between cat pontoons would mean that the pontoons would be trying to support the weight of the jon boat filled with water...because it probably WILL happen. The idea is setting off all kinds of alarms in my head. Not intending to be disrespectful or anything, just trying to suggest that this is probably NOT your best approach to getting on the water.

 

[BobGinCO]

Re: Sailboat Pontoons to Deck Boat Conversion

I don't think it is a crazy idea. But then again I have thought about mounting a mast and sail on my pontoon boat.

Seeing as how a typical pontoon boat IS a sail, with all that vertical tin above the waterline, it doesn't seem that far fetched. I know that recovering mine in a cross breeze is a real challenge!

 

[tuort]

Re: Sailboat Pontoons to Deck Boat Conversion

bobginco and waterlogged. I do appreciate the input. I use my jon boat in really large waves on a huge lake and never have a problem. I just slow down unlike a lot of more knowledgeable fast guys that plow on through and fill up with water. I have a small bilge pump that does extremely well. The coast guard inspects all homebuilt water craft in my area and approves them for number of people on board and engine size and for registration. Otherwise you don't get on the water here. The 14 foot boat will extend out on each end of the deck by about 2 feet. So whats the problem with this arrangement. maybe my explanation of natural bouyance levels for each unit was not clear. Actually just look at it as outriggers on a jon boat.

 

[tuort]

Re: Sailboat Pontoons to Deck Boat Conversion

I don't think it is a crazy idea. But then again I have thought about mounting a mast and sail on my pontoon boat.

Yea Man, Go for it. I believe it would work but would need dagger boards to prevent side slip. Its probably been done before but I have found out through a lot of living that no idea is a bad idea until you try it yourself. Now I don't mean jumping off a 10 story building with a umbrella but just try anything that seems reasonable. Get comments and all the advice possible but if your idea still burns in your head as you are trying to go to sleep at night then just do it.

 

[lncoop]

Re: Sailboat Pontoons to Deck Boat Conversion

Welcome aboard tuort. I think you misunderstood Glenn. I believe his concern is once the john boat is fastened underneath the deck it will quickly fill with water as you cross wakes, encounter chop, etc. and place a massive amount of stress on your design, potentially causing it to sag in the middle or do any of a number of undesirable things. It has nothing to do with your piloting skills. Just take a look at the motor pod on a party barge while underway and you'll see what I mean. I know a sixteen foot tandem royalex canoe full of water literally weighs a ton, so a twelve foot john full of water must be as heavy or heavier. He was suggesting that you might need to find a way to prevent this from happening. Should be doable. After all, the typical pontoon boat is sitting on nothing more than two sealed aluminum tubes, but you'd need to think the john boat in the center idea through very carefully due to the serious implications. Also, you might consider installing some sort of baffle system in your "center pontoon" so a leak in one area wouldn't fill the whole thing with water. Good luck with your project, and let me know if you need some Nascar decals. They're a dime a dozen around here.

 

[tuort]

Re: Sailboat Pontoons to Deck Boat Conversion

Welcome aboard tuort. I think you misunderstood Glenn. I believe his concern is once the john boat is fastened underneath the deck it will quickly fill with water as you cross wakes, encounter chop, etc. and place a massive amount of stress on your design, potentially causing it to sag in the middle or do any of a number of undesirable things. It has nothing to do with your piloting skills. Just take a look at the motor pod on a party barge while underway and you'll see what I mean. I know a sixteen foot tandem royalex canoe full of water literally weighs a ton, so a twelve foot john full of water must be as heavy or heavier. He was suggesting that you might need to find a way to prevent this from happening. Should be doable. After all, the typical pontoon boat is sitting on nothing more than two sealed aluminum tubes, but you'd need to think the john boat in the center idea through very carefully due to the serious implications. Also, you might consider installing some sort of baffle system in your "center pontoon" so a leak in one area wouldn't fill the whole thing with water. Good luck with your project, and let me know if you need some Nascar decals. They're a dime a dozen around here.

I didn't misunderstand Glenn, I agree I may need some cover over the Jon boat. I had thought of that but didn't write it in my first post. I am not yet concerned with all the dire predictions coming my way on this potential project. I have built many things and I believe this is very do-able. I asked for comments and appreciate them no matter good or bad. I guess you may be joking but the NASCAR thing is sort of getting old and you know what you can do with them.

 

[lncoop]

Re: Sailboat Pontoons to Deck Boat Conversion

I was indeed joking as referenced by the winking emoticon. This is one of the kindest and gentlest forums around, especially in the Pontoon section, but we enjoy teasing each other. It's all in good fun and shouldn't be taken personally, so, while I apologize for offending you, my suggestion would be to dial the sensitivity back a bit if you want anyone to provide any more meaningful input.