Predator powered jet boat

[firemanjim]

Long time no chit chat.... lol
Hey guys , I have a question. I'm currently building a smallish boat jet powered. I'm using the jet drive from a sea doo that had 60(maybe 65) HP.... and it was a 2 stroke. You know me, go kart nut at heart.... so I want to use twin 13HP predators with slight mods. Need to run a 1:3 drive ratio (no not 3:1) ...... I know this will drop HP and torque .
My real question is, do you think that's enough power to push a 4' wide semi v hull boat around ? Not looking for speed, just to put put my kids around. I have a jet ski engine, but that's what you'd normally use....
What do you guys think ?
And yes, still have the 32 and have changed directions a bit. I'll be working on that again real soon. And posting again....
EDIT
Boat should only sit about 6-7" in the water. I'll post some pics tomorrow, or go look at my videos on YouTube.... firemanjim324

 

[Whitetrashrocker]

I like your train of thought.

But. Water is heavy. Usually jet boats have rather large engines for a reason.
Just my 2¢.

 

[Nosandwich]

Great ! And if I reduce the force factor in a molecular atom splitter by 10% will it still work? JK IDK

Good to see you back Jim!!! Sounds doable to me


Gonna take it to Corpus, or a local lake?

 

[firemanjim]

I like your train of thought.

But. Water is heavy. Usually jet boats have rather large engines for a reason.
Just my 2¢.

Should plane fairly easy. Not looking for high speeds. I think I see what you're getting at with water being heat, but I've seen a 6.5 on jet driven boat of comparable size, but it only got about 4-5 mph.... and I don't think his gearing was right either.
I figured twin 13's running 4500 rpm , and at 1:3 , spin the drive shaft @13500 rpm.... The jet ski originally had 60ish HP and ran like 50mph or so . (Don't remember exact specs) The boat mimics the original ski bottom, sightly wider, but not much . The boats weight is projected to be approximately450-500 lbs. (Or about 100-150 lighter than ski )
If my thinking is correct, I should have no problem plaining out and cruise @ 15-20 mph.... I'm new to boat building. My first boat came out pretty good so I moved up to a bigger boat.
No sandwich..... the satire reminds me of someone.... lol
No not corpus, just around here more than likely. Maybe try out some bay fishing too.

 

[Nosandwich]

Why does everybody think I'm Poboy? ((Just because Nosandwich is a thinly veiled N.O. Sandwich? )

New Orleans Sandwich??? Couldn't possibly be aPoboy.

 

[firemanjim]

Why does everybody think I'm Poboy? ((Just because Nosandwich is a thinly veiled N.O. Sandwich? )

New Orleans Sandwich??? Couldn't possibly be aPoboy.

See, I never said who..... lol.....

 

[anickode]

Just a thought... For what 2 420s and mods cost, you could buy a 670 and get it into the ~40hp range for around the same money.

 

[firemanjim]

Just a thought... For what 2 420s and mods cost, you could buy a 670 and get it into the ~40hp range for around the same money.

The mods don't cost me a whole lot. I make the majority of all my stuff.....

 

[firemanjim]

Some pics of my current boat build....