Jet Jon... Good Idea? or Blasphemy?

tater76 · Apr 28, 2012

Hi folks,
so the other day I saw a Youtube video of a 12ft tin boat with a 750 jetski motor in it. It really peaked my interest, and upon further investigation I found that our New Zealand friends build these little powerhouses from scratch and have been for years. I think I would like to try it. Now for the controversial part... to cut a hole in a perfectly good tinny, and carve up a perfectly good jetski?? I know the tinny guys would rather die, as would the jetski folks, but would the benefits outweigh the dread of putting the saw to either? What are your thoughts?

MH Hawker · Apr 28, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

They were made in the US for a few years and didnt sell all that well and were dropped.

GA_Boater · Apr 28, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

From what I've heard a glasser makes a little bit better choice cause you can graft the bottom of easier. And the f/g is supposed to be quieter. I just saw a tinny with a jet ski drive at the ramp yesterday. Loud and fast. Find two junk boats and go for it.

Tnriverluver · Apr 28, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

Maybe not as fast or fun, just buy a jet outboard if you really need a jet.

erwinner · Apr 28, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

Someone on the tinboats.net forum did this and they had problems getting the water to intake into the jet. You have to design the bottom specially to route water into it.
But I say go for it!

NYBo · Apr 28, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

Bondo · Apr 28, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

tater76 said:
Hi folks,
so the other day I saw a Youtube video of a 12ft tin boat with a 750 jetski motor in it. It really peaked my interest, and upon further investigation I found that our New Zealand friends build these little powerhouses from scratch and have been for years. I think I would like to try it. Now for the controversial part... to cut a hole in a perfectly good tinny, and carve up a perfectly good jetski?? I know the tinny guys would rather die, as would the jetski folks, but would the benefits outweigh the dread of putting the saw to either? What are your thoughts?

Ayuh,.... How weedy is it where you go boatin',..??

kfa4303 · Apr 28, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

It is intriguing and can certainly be done, but I think they work best in shallow, rocky, non-weedy environments like Bond-o said. I would think they'd also be pretty loud, especially in a tin boat, but if you aren't worried about the noise it could be fun. Lots of folks fish shallow near me, but they try to be as quiet as possible and pole around. Overall, they seem like sort of a utilitarian, one trick pony, but I bet they're fun to yahoo around in.

Mikeyboy · Apr 28, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

It sounds like a fun project just to say you did it, but I don't think it would be that practical. Having said that I say go for it. Start a build thread so we can follow along.

tater76 · Apr 28, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

Thanks for the input folks, I think most of you are right on about the sole purpose of the craft. Loud, fast, and nimble make it kind of a shallow, rocky, weedless machine. Every vid I have seen shows the captain wearing ear muffs LOL! but they look like they can handle pretty knarly stump infested water. That brings me to my next dilemma.... Just how much junk could a jetski impeller shred??? If I build one, I want a riffle riding, stump jumping bruiser capable of handling rocks and trash. The only next step up for me that could handle it would be an eXtreme shallow jet. Its like a flat jon with a 250 Merc inboard, straight nasty machine that can run in 3-4" of water.
I can fabricate rock busting 1/4" aluminum up to the intake no problem, but will the jetski pump handle what the bigger ones will?

tater76 · Apr 28, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

Oh, and where I would like to boat can be weedy in the later summer. The Snake River gets pretty mossy starting late June, but I would also run it on smaller, colder, weed free rivers.

H20Rat · Apr 28, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

tater76 said:
Every vid I have seen shows the captain wearing ear muffs LOL! but they look like they can handle pretty knarly stump infested water. That brings me to my next dilemma.... Just how much junk could a jetski impeller shred???

Pretty much none... PWC's, modern jet boats, and jet outboards all have one thing in common, they absolutely do not like injecting ANYTHING. (I've owned all 3 of those at one point) The only type of jet that will be ok with that type of abuse are the ones you connect to a big block car engine. (berkeley or hamilton)

26aftcab454 · Apr 28, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

smokingcrater said:
Pretty much none... PWC's, modern jet boats, and jet outboards all have one thing in common, they absolutely do not like injecting ANYTHING. (I've owned all 3 of those at one point) The only type of jet that will be ok with that type of abuse are the ones you connect to a big block car engine. (berkeley or hamilton)

the old school jets hate to ingest rocks.

tater76 · Apr 29, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

I was afraid you guys might say that, but I still think it would be a fun project. So... that brings me to the next question, if I have a 12 footer how big of a ski motor should I, could I get away with? 550, 650, 750, 1100!? I'm thinking the bigger the better

but the stresses of an 1100 on such a little boat??? I would likely only carry myself and a few gear related things aboard, so it would stay fairly light. What do you think?

PSG-1 · Apr 29, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

Here's one of my boat running some shoal areas in the lower Little PeeDee River in South Carolina:

http://www.youtube.com/watch?v=qOf-YRXS2KI

This is a 1997 DuraCraft 1648SV with a Yamaha MR-1 High Output engine that delivers 160HP @ 10K RPM.

Oh, but that video only shows it running in freshwater, with white sandy beaches. How's it do in salt water, around oyster rocks, etc?

http://www.youtube.com/watch?v=jNOoOPv1SQM

Pretty good, I'd say.

How fast is it?

http://www.youtube.com/watch?v=e4_cpUwnYX8

What does it take to build something like this?

http://www.youtube.com/watch?v=_I0Tod7-FXY

It can go from a thousand dollars, to several thousand, depending on what type of boat, type of engine, etc. Most jet john owners build their own boats to suit their particular use.

Some of them are really well built, and some are poorly built, and require flight deck earmuffs to operate because they are extremely loud (again, that's improper build procedures)

But if you want to know more about them, give me a holler

tater76 · Apr 29, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

PSG-1..... NOW THAT'S WHAT I'M TALKING ABOUT!!!!!!!!!!!!!!! LOL!! I had seen another boat done this way and thought it was sweet, but yours is what I'm looking for. A truly multi function boat that appears to be able to handle the rough stuff. Now you've got my creative juices flowing! You will be hearing from me soon, and thanks to everyone that chimed in. I will try to make a step by step thread for everybody as soon as I gather the materials.

PSG-1 · Apr 29, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

Not a problem, glad to give you some ideas. When I first built my boat back in 2005, there were a lot of nay-sayers, they told me it was a waste of time....one guy even told me somebody he knew tried to build a jetboat, and it only went 9 MPH!

I'm so glad I didn't listen to them!
(When they saw my boat owning the creek at low tide, they pretty much sat down and had a warm cup of shut the heck up....LOL)

You can find some more detailed information on my boat build over at the tinboats.net forums, look under johnboat conversions for "Aluma Jet"

Lots of other videos of the boat on my youtube channel, as well.

Jlawsen · Apr 29, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

To addresss the weed situation, you won't have any more problems with that then you would with a jet ski. Merc has been making the sport jet motors for years and JetCraft runs them in several of their boats. That would be a bit big for your 12' but the jetski motor would probably be fine. The only thing you'd need to address is the center of balance but that could be overcome by moving the gas tank up forward probably. If you put a stomp grate on it, it will take care of most of the weed problem, the moss and algae will blow right through without a problem.

The mount wouldn't be all that hard. You basically build a box frame out of aluminum flat bar and then cut the bottom and the back of the transom out as needed to fit the intake and the nozzel. And, you are correct, it's been a real hit in New Zealand. If you want to talk to somebody that knows that stuff in and out, call Mike Taylor in Yuba City, Ca. He's from New Zealand and was heavily involved in the sport there. He's in the states now and he and his wife Maggie own Jet Stream Concepts. I'm sure he'd love to hear your about your plans and probably offer up a lot of very skilled advice. http://www.jetstreamconcepts.com/?lang=en&sub=home

Part-time · Apr 30, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

A jet doesn't have a tenedency of sucking up weeds or gravel unless you're at a stand still and hammer the throttle, then it will act like a giant vacuum cleaner.
If you go with a thrasher style, 2 stage hamilton pump, the weeds will get chopped up and blow right thru the pump. Berks, Jacuzi and what I've seen on sea-doo's don't like weeds so much.
I have a similar project in mind, I already had the bottom of a sea-doo that had a blown motor cut out, but I X-ed it when I got my hands on a Jacuzi xj for a couple hundred bucks...
now I'v got me an 18' starcraft bowrider that was powered by an OMC stringer (there's already a big hole cut out for the pump and the floor is made to mount an engine to) and I'm on the look out for a 2nd gen RX7 engine (turbo charged rotary) to turn the pump.

mrdancer · Apr 30, 2012

Re: Jet Jon... Good Idea? or Blasphemy?

Bubba1235 said:
tater76

Afraid you are getting some poor comments about jet drives. Check out Phantom Jet Boats, rocks and weeds don't mean much.

http://www.phantomjetboat.com/

...

If you are on a budget, you could save a few thousand by getting the boat directly from SeaArk, who makes it for phantomjet. I think Phantom just adds some decals and maybe some additional interior fabrication.

Jet Jon... Good Idea? or Blasphemy?

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