Jet powered Cracker Box

About using jet ski motors to power small boats

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Lewis Barrett
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Location: Cartersville, Ga.

Jet powered Cracker Box

Post by Lewis Barrett » Mon May 24, 2010 7:14 am

I have the Cracker Box plans and had a crazy Idea this weekend for a scaled down version with a Yamaha powered jet. Where some people have scaled the Squirt up to 12 feet to hold a jet set-up, I was thinking of doing the same thing by scaling the Cracker Box down from 15' to 12'. I would switch the motor to the rear and move the cockpit forward.

Now I need feedback. Will this work????

Let me know.

Thanks

David

lakeracer69
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Re: Jet powered Cracker Box

Post by lakeracer69 » Mon May 24, 2010 10:30 am

If you're going to do that look at the Tiny Might plans.
As Conan the Barbarian says, " It's not how hard you can hit, it's how hard you can get hit and remain standing".

Lewis Barrett
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Location: Cartersville, Ga.

Re: Jet powered Cracker Box

Post by Lewis Barrett » Mon May 24, 2010 12:23 pm

I already have the Cracker Box plans and I would need to modify whatever plans I got anyway for the jet system.

I was thinking about shrinking everything down 20%.

This would be a father son project.

David

Nova SS
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Re: Jet powered Cracker Box

Post by Nova SS » Mon May 24, 2010 4:23 pm

Why shorten it? I suspect the cost difference to build would be negligible. Just wondering is all. :)

Lewis Barrett
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Re: Jet powered Cracker Box

Post by Lewis Barrett » Mon May 24, 2010 7:27 pm

Nova ss wrote: Why shorten it?

I guess I thought it would be kinda cool looking. I'm not only looking at shortening it, but also decreasing the beam as well. I'm basically going to scale everything down. Also, I Just finished a Monaco and don't want to tackle another big boat right now and the Jet ski motor I have would be too small for a 15 foot boat. I would be looking at reducing the hull weight from 400# to somewhere around 275#.

I'm just playing around with the idea right now. My 10 year old son is fueling the fire and he's ready to go but I'm not so sure. We'll see.

David

Nova SS
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Re: Jet powered Cracker Box

Post by Nova SS » Tue May 25, 2010 3:42 am

I know you said you had the plans for the cracker already but what about taking a look at a dyno Jet. Its designed for a jet ski motor already and has the layout your talking about.

Lewis Barrett
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Re: Jet powered Cracker Box

Post by Lewis Barrett » Tue May 25, 2010 6:02 am

You are probably right Nova, In the end the cost of the drawings is really nothing.

David

upspirate

Re: Jet powered Cracker Box

Post by upspirate » Tue May 25, 2010 6:53 am

I think the Tiny Mite would be the way to go....it has the Barrelback look you want,everything fits to scale without guess/modifying beam,height,sheet planking fit etc.

A set of plans/patterns would be far cheaper than messing up on expensive wood plus lots of wasted labor

Only thing I think would be a consideration ,is the flat bottoms on these boats....jets kinda like vee bottoms to keep the pump buried.

But others have had success with flat bottom jets IE Squirts and TNT's

The Dyno Jet has the bottom and is designed for a jet,but the hull is a more modern design,not the classic design I assume you are looking for.

Lewis Barrett
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Re: Jet powered Cracker Box

Post by Lewis Barrett » Tue May 25, 2010 8:15 am

That's right Pirate, the classic look is what I want, but this is going to be my son's project and he already said how we could paint it :shock: :?

I'll try and convince him the classic look is the way to go.

If I did go the Cracker Box way, I would increase the dead rise a little to get the jet deeper in the water.

I was searching around the forum looking for anybody who put a jet in a CB and found this guy: web letter 86 Rick Heaney. Of course his boat looks great but he did way more than I want to bite off right now. I think he even stretched it a bit.

David

Nova SS
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Re: Jet powered Cracker Box

Post by Nova SS » Tue May 25, 2010 10:43 am

if you graft part of the bottom from the Jet Ski into the bottom of the boat your intending to mod that would likely create a small V at the rear of the hull. I believe a few builders have done it this way. The Problem with the Tiny might and Cracker would be weight distribution if you move the seating forward enough to accomidate the jet drive behind the seating (if I'm understanding your vision correctly)

Lewis Barrett
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Re: Jet powered Cracker Box

Post by Lewis Barrett » Tue May 25, 2010 11:14 am

I think I see what you are saying Nova, however, my logic goes something like this...If the Cracker had a small block chevy that weighed around 800# sitting in the middle and you had 2 grown men riding say 225# each you would have 450# at the rear. The weight difference would be +/- 350#.

If you moved the cockpit forward now you would have 450# at midway and a much lighter motor in the rear say around 200# making the weight difference +/-250#. When you factor in the reduced size in the boat the weight difference is basically the same. :? :? :?

If I did the jet system I more than likely would graft the ski into the boat.

David

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BulldogBoater
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Re: Jet powered Cracker Box

Post by BulldogBoater » Tue May 25, 2010 7:12 pm

Lewis,

It will work and it will be awesome! The shorter the drivetrain the better (I'm partial to SeaDoo) and the grafting is easy. I would leave as much vee from the Ski below the hull as possible - I wish I would have on my Squirt.

I look forward to your updates.

Kevin
"I'm not trying to get it perfect. I'm trying to get it finished!"
Strip Planked Skiff, Jet Squirt, 2 Tubby Tugs, Console Skiff, Modified Kingfisher (Last One #6)

ScottyJ98
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Location: Southgate Michigan

Re: Jet powered Cracker Box

Post by ScottyJ98 » Sat Apr 23, 2011 6:34 pm

If you were to graft the pump cavity of the jet ski you are pulling the motor from you could search the jet ski forums for a toploader intake grate. I use them on my stand ups to help feed water in to the pump and keep it hooked. I'm kicking the idea around of building the tiniy might with a jet ski engine and pump caqvity grafeted in to it.

gotasquirt
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Joined: Mon Apr 05, 2010 12:10 am

Re: Jet powered Cracker Box

Post by gotasquirt » Mon May 09, 2011 1:36 am

just use a yamaha pump from a wave runner 3 it has an intake that is made of aluminum i have used it in 3 boats that i have built just my 2c will

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steve crawford
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Re: Jet powered Cracker Box

Post by steve crawford » Thu May 12, 2011 6:24 am

It is way simple to put a slight V into the frames and blending into the grafted hull. No mater how sharp of a turn I would put my boat into it would never suck any air....Besides their are no flat bottom jet skis so that's why I modified mine...

If I had it to do over again I would go with the Dyno Jet , quicker build and lighter..

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