need advice

[stinkbait85]

i have been tossing this idea around in my head for a while now and have even done a little web surfing on the subject. however most of the pages i have found are on 12 to 14 ft jons and only show pics or videos. i am thinking about putting a jetski motor in a 2072 sea ark. the questions i have are:
1- how do you keep the intake from sucking up debris?
2-how to you rig up the steering? i wanna use a center console
3-how big of a jet ski motor should i use? considering a fully loaded boat for me would weigh in the 1700 to 2000 lbs range
i do alot of fishing in shallow rivers and go through several props every year and the cost of an outboard with a jet drive is too much for my wallet and since i get a bunch of crap from friends and family for hacking up perfectly good things to do what i call "necessary modifications", i figure...why not? so.....help me out. fuel my madness.

 

[osborn159]

Re: need advice

i dont know how to answer your ?? but i have seen these around here in smaller j boats, usually done just for effect(i think), id go as large as is fesable on the powerplant pushing that much load, ive always wanted to make one of these, cant justify the cost for a toy. love the concept tho.
D

 

[SBTOM]

Re: need advice

Haha... this sounds like a fun project! You should ask around in some of the PWC forums, but I think that some of those supercharged waverunners put out 110+ hp so that should get you up and moving. Not sure about torque though.... you might have better luck trying to get a motor/jet out of an old jet boat as it would already be set up for this type of thing. Definitely post pics when you get this thing going!

 

[huntxtrm]

Re: need advice

I'm fixin to do the same thing. I've got a seadoo gts, book says 57 hp and 587cc. lookin for about a 12 to 14' john to put mine in. May have one located. Like to know a few tricks myself. Maybe we can swap info and experiences? Wanna use mine for river fishin in the shallows, and bowfishin. I've been readin on it some. got a few tips here and there. when I start my build, I'll post it step by step. maybe we can compare notes? maybe we will get some constructive critisism? Maybe just hand slappin, who knows?

 

[huntxtrm]

Re: need advice

far as suckin up rocks, i've read about installing a grate over the intake 1/4" apart vertacle, horizontal will make it cavitate. I'm told. I plan on installing stainless impeller to chew up weed and debris that make it through.. slow in shallow water picks up debris, haulin you know what does not. apparantly intake is moving to fast to pick up rocks. Rest I'm gonna experiment with, i recon.

 

[erikgreen]

Re: need advice

As far as avoiding rocks, check out what type of grate or intake either jet skis or jet boats (like the ones from sugar sand) use to avoid that sort of thing. It's not actually that huge a problem.

FYI, a 2000 lb boat with a 100 hp motor isn't going to be really fast.. I'd go for the biggest jet ski motor you can find. The jet boats (the two seaters) you see have either the biggest motor around (or two of 'em), and they're small and light craft.

You can figure the HP equivalent of a jet ski drive to be about half or less of an outboard or prop drive at the speeds you'll be able to get... jet drives are only efficient at fairly high speeds, so until you get upwards of 20 knots you'll have power available equal to roughly a 40-50 horse outboard if you have a 110 hp drive. There's a reason why those fast jet boats from the 70s have 455 hp olds engines.

A lighter boat, like a jon boat, might work decent for this sort of thing, but if you want a shallow water motor, I'd consider either a mud motor or a much bigger engine... unless you like trolling at high RPM.

Erik