Looking to build a pontoon type boat with catamaran hulls

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griggsmars

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I am looking to build a pontoon type boat approx 24' to 30', with a small outboard. It will be used mostly as a floating island, from which you can launch jet skiis, hang out in the sun, swim, etc. The boat will be kept in Shark River bay most of the time, but I would like to be able to bring it out into the ocean when it's not too rough. I have been navigating and surfing these waters for 30+ years so I am well aware of the rapidly changing conditions. Here comes the question- would using catamaran style hulls as opposed to pontoons give the boat more stability, and better handling in choppy water? I have no problem with a deeper draft to gain these things. Thanks, MIke
 
poontoon

poontoon

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Re: Looking to build a pontoon type boat with catamaran hulls

A pontoon is essentially a catamaran hull, just that it's constructed out of aluminum verses fiberglass. For choppy water, The handling characteristics of a true catamaran fiberglass hull are usually not realized until you reach a speed where it's trapping enough air to provide a sort of cushion to ride on. My cat starts riding like a caddy at 60. Anything below that it's a coin toss based on the conditions.
 
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mrdancer

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Re: Looking to build a pontoon type boat with catamaran hulls

The biggest difference will be that most pontoon hulls are just round tubes, meaning that once they are submerged by more than halfway, they have decreasing reserve buoyancy. Not a big deal in most situations, but could be if you run heavily loaded.

Personally, I think the aft end of a pontoon hull should be shaped like an upside-down T - that would give you a planing surface if you had the power to do so, and a tapering hull at displacement speeds to give better efficiency. However, it would cost a little more to manufacture, which is why I think you don't see it put into practice.
 
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mrdancer

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Re: Looking to build a pontoon type boat with catamaran hulls

p.s. - there are regs out there that specify what your boat needs equipment-wise depending on size. 26' is the magic number - go over that and you will need more/better safety equipment, depending on where you live. Check your local regs...
 
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shrew

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Re: Looking to build a pontoon type boat with catamaran hulls

I'm not sure if there is enough information to provide a reasonable answer. In my opinion the Max. Load of the vessel is probably the most accurate number. It sounds like it's going to be used as a 'mothership' of sorts for surfing and jetskiing. The Hobie 16 (for example) has a Max Load of 800Lbs. A Sun Tracker 18 has a Max. Load of 1700lbs.

Without really being able to compare apples to oranges it's difficult to say.
 
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Chris1956

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Re: Looking to build a pontoon type boat with catamaran hulls

The answer is yes, PowerCat-type hulls will give a better ride than pontoon hulls. The deeper vee of a cat will cut the water better and ride better.

Cat hulls will also increase freeboard which is a good thing. However, it will make launching a jet ski a challenge. You will need a V4 outboard(twin OBs will be much better) to have any decent performance and it will be better to fight the currents by the bridges.
 
DuckHunterJon

DuckHunterJon

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Re: Looking to build a pontoon type boat with catamaran hulls

Heed Chris's advice. When I was younger, my boss lived on the river. One summer, we decided to build a floating platform to swim from. He had access to pontoons, so we put 3 pontoons under a 16' x 20' platform. It worked great, we pushed it out into a cove, anchored it down, and swam/hung out on it after work many days. One day, my boss gets to tinkering, and in a few minutes, he has an aluminum plate fabbed up on the back of the platform to mount one of the rental boat motors (merc 9.9's). We figure load up a cooler, and take it out to the mouth of the river (about 1/2 mile down from his house) and hang out at the sand bar. Going out was no problem. Getting back was. The 9.9 would not move it one inch forward against the current. We ended up calling his wife to come out with their Penn Yann and tow us back. We still made the same trip several more times, but planned ahead for a tow home. All and all, it was great fun. I think he's still using it and that was 15 years ago.
 
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griggsmars

Petty Officer 3rd Class
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Re: Looking to build a pontoon type boat with catamaran hulls

Thank you, everyone has great advise, I will probably go with that 26' number, I hope to be able to hold at least 10 people plus seating, coolers etc. I would also up the engine size to gain more power, ( at least 150hp or maybe 2 smaller motors) as it is true getting in and out of the inlet can be difficult. The problem is, I don't think a standard pontoon boat is going to be able to handle what I'm asking of it. Now the question is- will I gain enough in performance, and stability in the ocean by using the catamaran hulls to make this venture worth while. Also, will I have the necessary bouyancy? I would rather spend more money and greater effort to end up with a vessel that will have more versatility, and the ability to venture into the ocean. Then, where do I get these hulls, or do I have to build them? Thanks again, Mike
 
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