Pondering HP of jetski engine for a glass boat conversion

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Crawfish Dundee

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I am pondering the idea of inserting a jet ski drive train into a 1975 fiberglass Starcraft 15 foot tri hull project boat. I need a motor when the time comes anyway, and I do not know a thing about the jet ski world, never rode one, and never owned one. So I am wondering what I should be looking for in a used jet ski system with reverse. The hull is rated for a 95 hp max. I have a couple of years to do this job as my drawing board has many project on it already, but I would like to keep an eye out for a system along the way. Any ideas?
 

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ondarvr

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Why put a bunch of time and money into something that won't be very good even if you do a great job, let alone the value being Zero when finished.

​Take on a project that at least has some hope of being useful when completed.
 
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Crawfish Dundee

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Why put a bunch of time and money into something won't be very good even if you do a great job, let alone the value being Zero when finished.

​Take on a project that at least has some hope of being useful when completed.
What does it matter to you? My time, my money, my dream, my challenge, and it will sell, there is a market for everything. And it has been done before.
 

Scott Danforth

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your time, your money, your folly..... personally think would be a waste of a jetski driveline and a hull as well as a few thousand dollars and a few hundred hours......
 

GA_Boater

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Your boat, your time and your money - Go for it if you want to do it.

The bare tri-hull is heavier and puts more hull in the water, where a ski hull is lighter and much less drag in water. Look for a higher HP donor ski and forget about the 95 HP rating cuz the OB won't be hanging on the transom.

Offhand, can't recall any names, but you should be able to Google some site/forums with conversion projects.
 

ondarvr

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I run jet boats all the time, so I'm very familiar with them, and with conversions, that's why I said choose something that will be of value when you're done with it, an old tri hull isn't a good starting point for much of anything, better old hulls can be found for free. The main reason for the jet is shallow water, which means a light hull, so aluminum is the material of choice. If this is for open water a prop is far better. PWC pumps tend to be low volume high pressure pumps, they work better with lighter hulls that can go fairly fast.

 

Crawfish Dundee

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I run jet boats all the time, so I'm very familiar with them, and with conversions, that's why I said choose something that will be of value when you're done with it, an old tri hull isn't a good starting point for much of anything, better old hulls can be found for free. The main reason for the jet is shallow water, which means a light hull, so aluminum is the material of choice. If this is for open water a prop is far better. PWC pumps tend to be low volume high pressure pumps, they work better with lighter hulls that can go fairly fast.

Now thats news I can use, thanks.
 

Scott Danforth

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A small hull like a GW invader or similar would be a good candidate for PWC power. A small custom aluminum hull would also be a good choice.
 

Crawfish Dundee

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Well, it's a different day, and I think I am going to shelf this idea for long while. Thanks for the advice everyone.
 

jimmbo

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As mention earlier, the hull would not be a good choice for a jet drive, the hull doesn't have pad to ensure an uninterrupted flow of water, and any type of scoop to channel water to the impeller would be just that, a scoop for sand, gravel, and even rocks.
As for engines, Canadian company Bombardier, makers of SeaDoo and Evinrude Outboards does make some high power engine and drives for their SeaDoo boats
 

Vikesfan

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Sounds like a fun build. I would start by looking at some of the jet boats already powered by a PWC motor like the Yamaha XR 1800 or LS 2000 and Sea-doo Speedster or Challenger boats. No need to completely reinvent the wheel. Those boats use the same engine and driveline parts as the PWC so that should give you some direction on your build. You could find a 2 stroke motor and pump setup pretty cheap, but would get so much more performance from a 4 stroke, although the additional weight, cost, and complexity could be an issue.
 

GA_Boater

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Well, it's a different day, and I think I am going to shelf this idea for long while. Thanks for the advice everyone.

And the advice keeps coming for some reason. :doh:

CD - Gonna close this for now. If you change your mind about proceeding and want it reopened, PM any Mod.
 
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