Custom built aluminum jet boat 2008 STX 15F 160hp motor and 155mm pump

[riverassasin]

Hi All this is my first post although Ive been on the sidelines reading as a non member for a while.

4 years ago I had a boat built for me by a couple talented guys. Im not mechanical, although I understand basic concepts.

The boat is 3/16 aluminum bottom with 5/8 virgin UHMW
14 feet long
5.4 wide on the bottom

I found a crashed ski with fairly low hours, as I recall 60 hours, now maybe 120 i used this as the power plant, it came with a 148mm pump.
top speed was 4oishmph, fairly snappy
I upgraded to 155mm pump in hopes to gain more snap, its was mildly better.

I had a some trial and error in testing different impeller sizing, now I have 9/15 with a inducer

when i had the wearing sleeved with stainless steel, stator rebuilt and new impeller and inducer
it was pretty snappy
top speed was about 42-43mph at 7500rpm, I think i peaked the system

recently I had a new wear, impeller, inducer rebuilt and now my stats
top speed 36-38
not near as responsive

I've been thinking.....Ill keep this boat for a long time, weighing out swaping the motor or super charging this one if possible, super charging seems like the easiest cheapest option but Im open to a new motor. I want it to rip and be very reliable as I get to some unique places down rivers that if I have boat problems it would be an issue getting back home. The boat has way more surface area than a jet ski, so it wont be near as fast as a jet ski, but it would be cool to hit 50-55mph and get there quick. I jet small rivers that get extremely shallow, so light weight it also important and a good hole shot to get me on plain fast.

I was mostly satisfied with my old stats, responsive and 42-44mph, why do you think its not as fast any more, stator should have been rebuilt, my mechanic said it didnt look bad, motor is slower, thoughts?

What would super charging look like, is it even an option (im not mechanical sorry if thats a dumb question)
pros - way fast more enjoyable boat
cons - maybe more things break, sand, rock will pump through at a much fast rate? Could I have a stainless steel stator built to handle more abuse?

Or is there another motor/pump thats somewhat compatible so I dont have to build the whole boat to make it work

heres a couple video of the type of boating we do




thanks for your help

[steve45]

Very interesting! I have a neighbor that has built a couple of similar boats, but I don't know much about them. He came over one day, interested in buying an old 'Ski to rob the engine out of, but it wasn't powerful enough.

The 1500 cc engine that you used looks like the same engine that's used in the Ultra 310, but it's not. You could find a wrecked 310, but supercharging your engine really wouldn't be a good idea.

How about some more pics of your boat? I'd love to see some of the design details.

Bow fishing looks to be a lot more interesting than just using a hook!

[riverassasin]

I dont know how to attach pictures....

[steve45]

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