Best balance of a Pontoon Boat

[Mark Emaus]

I have the luxury of being able to put the engine anywhere on the boat.

Having said that, what is the best way for a pontoon boat to travel through the water. Should the pontoon be able to plane out and is it better to have the majority of the weight in the back or have the power pull it out of the water and the weight as even as possible around the boat? thanks

Mark

[marshmat]

Hi Mark,

The outboard engine on a pontoon boat, like most small craft, is generally located on the centreline near the stern. A bracket on the aft crossbeam is the customary way to mount it, sometimes with a small pod to shield the engine from the wave action between the hulls.

Midships- and forward-mounted outboards have been tried, but haven't caught on, as they seem to offer no real advantage and numerous disadvantages (steering being the main one, a midships-mounted outboard has no leverage to turn the boat).

A round bottom pontoon won't really plane out, it'll just plow along faster and faster (the bows will rise somewhat, and it'll cross its bow wake, but there's not really any significant planing lift). If you're fortunate enough to have one of the new V-bottom pontoons, these can plane pretty well (albeit not as well as a ski boat or runabout).

A pontoon boat's engine is a relatively small fraction of its total weight, typically less than 10%. The seating layout and/or cargo placement is the only real control you have over the balance and trim of such a craft.

[Mark Emaus]

Matt,

Thanks you foryour help.

I should have put more info in my thread. The toons are of a the high tech design. The engine we have is on deck and will be treaded like an inboard. However, we are looking at Hyd power so placement of the engine can go anywhere. The reason for hyd, (before anyone jumps on me) is where we will use thye boat. We need to go through mud and junk in shallow water.
We have not set in stone the the hyd. option, but I am treating this thread as if we are going to use hyd.

[marshmat]

If you're using a hydraulic drive setup, thus giving complete freedom in engine positioning, you may as well put the engine somewhere easy to reach and out of the way. Under the helm console would seem to be a logical choice, but it'd be nice to see some sketches of the boat.

I'd be really curious to hear more about how you're thinking of setting up the hydraulics, such as what motors you're using, how you're doing the shaft/prop/seals, etc.

[Village_Idiot]

I'd be curious to know how you are going to cool the engine, since that is generally a bigger obstacle to running in shallow, dirty, muddy waters than the propulsion unit itself.

You might do a search on the 2coolfishing boating forum. There is a fellow on there who did a "pocket" tunnel on a pontoon boat to run in shallow water with an outboard. He said it worked well, although it looked like there was a lot of room for flow improvement around the prop.

If I were doing it, I'd utilize wide low-height pontoons with a shallow-v bottom (like Clark's pontoon boats), then craft the space between the pontoons to direct flow upward to the rear, where an outboard on a jackplate can run well above the bottoms of the pontoons themselves (like a Flatscat). Add a good cupped prop and you should be able to run in six inches of water on plane, if the rest of the boat is well-designed.

[Mark Emaus]

We are using a VW engine which is air cooled. The engine will drive the Hyds. and should staycool enough to operate in the conditions we are asking it to do.

[Oyster]

There is a simular hull using a corvair engine and airplane props simular to airboats, even one that I saw last fall incorporating foils with its own fan for the bottom. Maybe an alternative???