Diesel jet drive or electric I/O?

I'm looking for propusion ideas for my 15.5' tri-hull. The boat this year will be used just for fishing with my young sons in local lakes and resevoirs with a trolling motor on the transom. However, boys being boys, I think we'll be doing more exploring than fishing. Steaming up tiny tributaries, landing on small islands just to walk around, and the inevitable "Daddy this looks like a good place to jump overboard and swim".

In rebuilding the stringers and deck, I will incorporate some sub-floor flotation foam near the sides to try and reduce the vessel's draft for the occasional shallow run. The floorplan I have laid out is very open, with only forward and aft casting decks outstanding.

In order to continue the exploratory adventures, I'd like to integrate a longer-range propulsion system for next year. I am open to any suggestions, especially if they involve shadetree fabrication.

 

Sorry, but this won't do anything to reduce your draft, it will only help keep the boat afloat if she were to become swamped. Personally as far as propulsion goes, I'd just hang an outboard on her as I'm pretty sure that's what she was designed for, since you didn't mention a stern drive. This is the simplest, and usually the cheapest route, especially if you're not going with a lot of power. Just my 2 cents, but I hope it's helpful.

 

Thanks Skipper. I guess I will scrap the floatation foam idea. I hadn't done any research on it yet, but thought it might help. Yes, the boat was originally designed for an outboard, and, as silly as it seems on such a small boat, it originally had a console with remote controls. I would feel like such a wannabe sitting behind the wheel of a boat that old that has no classic or nostalgic qualities. The completed version of this boat I have in mind is very bare bones--like an old Kenner or Ski Barge--but its uses will be more like a jon boat.

As far as outboards, I just turned down a 20 horse Johnson with stick steering and an old Ship Master control box, simply because I saw it as another time consuming item that would delay the boat's maiden voyage this year. If an outboard is my next propulsor, then I would love to have a Johnson 9.9 or 15, tiller steered, of course. The old ones that could be started by spinning the flywheel by hand. A newer four-stroke would be a good setup, too, since off-the-line torque is not desired. The quietness at trolling speed would be a nice bonus, too.

But I still want input on this topic. Who else has offbeat ideas? How about a Kobota diesel with a surface drive?

 

Passin through the threads and I saw your post.

My father had a 14 foot aluminum v-hull fishing boat with a 2-stroke 9.9 Evinrude outboard. While it was great for fishing, it wasn't going anywhere in a hurry.

From what I have heard 4-stroke engines have less "power" than the 2-strokes. Theoretically from the 2-stroke having a "power stroke" every rotation and the 4-strokes every other rotation. I've heard 4-strokes and they are quiet though!

So I might be careful on choosing the right horsepower engine for your vessel.

Hope this helps a bit.

 

Well i'll throw in my 2cents worth.

First, yes, the floatation thing wont help, unless you hole your boat or swamp it. However, it might be worth putting some form of floatation in there, as if yuo are going to be explorering the unknown so to speak, might be some added safety incase you hit something, should keep it afloat long enough to get to shore at least. Just an idea.

Engines. well outboard is for sure the way to go on that. least space, lightest weight, easiest solution. jobs a gooden. How big is the big question. My main concern is the hull. Without seeing the boat i dont know, but i assume it is a planing hull? These are great for going fast, but at slow speeds have a large wake normally. At very slow speeds like tick over up small inlets etc, no problems, but getting to the inlets might be hair raising to say the least. I would get an engine that is capable of getting the hull on the plane, so out on the open water, your not dragging your stern along producing a huge wake, and really straining the engine, which not only sounds nasty, wastes a lot of fuel too. you find you use more fuel trying to push a planing hull flat out with an engine that cant get it on the plane, than you do planing with a bigger engine. Boat that size 9.9hp isnt going to have what it takes to do this. I doubt the 15 would. it might with just the 2 of you and playing around with the weight on board to trim it right. i would go for around a 25hp personally. That should be enough to do what you need to do. a 4stroke would be quieter and cheaper to run. Depending on your budget. Obviously make sure the outboard has an easy way to trim it. be it manually or electronically. as from what you say, you are going to need to be able to trim this engine up out the way on short notice. Engine with a trolling lock position is ideal, so you can lock it trimmed right up to the water surface and still maintain drive, all be it not 100%, and keep it up out the way of what ever is below you. Just dont reverse to hard with it like that. else your all going to get very very wet.

Thats my opinion anyway