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View Full Version : Boat-Impeller size-RPM?


502 JET
05-07-2006, 06:53 PM
Does the weight of the boat or the hull configuration have anything to do with the engines ability to turn the impeller at max rpms?
If you put the same engine and pump in two different boats like a small v-hull to a large day cruiser would the engine turn the same max rpms in both boats?Will the larger heavier boat run less rpm?
gregr1971
05-07-2006, 06:57 PM
i took an engine and jet out of a sleekcraft executive 26', put it in a 20' tunnel hull jet, and turned exactly the same rpms, so i can say that it does not effect the rpm's, the pump doesn't know what size boat it is in.....
jbone
05-07-2006, 07:21 PM
Interesting :idea:
I always thought my heavy boat held the rpm down. Now I'm very confused.
Sooooo, a heavy boat will turn the impellor the same rpm, but will go slower than the same set up in a light boat... right???
J
Oldsquirt
05-07-2006, 07:26 PM
Sooooo, a heavy boat will turn the impellor the same rpm, but will go slower than the same set up in a light boat... right???
J
Yep.
gregr1971
05-07-2006, 07:28 PM
just remeber, oldguys know what they are talking about...............just kidding!!!
Nubbs
05-07-2006, 08:11 PM
An engine is capable of making "X" amount of power. The size/weight of the boat does not change the amount of power the engine is capable of making.
SmokinLowriderSS
05-08-2006, 04:37 PM
An engine is capable of making "X" amount of power. The size/weight of the boat does not change the amount of power the engine is capable of making.
Right, and the pump has no idea what it is attatched to other than it is attatched to a motor trying to spin it.
Danhercules
05-10-2006, 10:44 AM
Its like when a prop boat trims out just right, they will see a gain in RPM, but with a jet, no matter the trim, your RPM dose not change, just your speed. With a jetboat, your pumping water.
Taylorman
05-10-2006, 10:52 AM
So hows the deck boat Dan? I really like it and would love to have one one day.
Danhercules
05-10-2006, 11:08 AM
Still playin with the ride plate. This weekend she was at 61.2. I got a lesson about driving a tunnel in chop. DAMN. It sure is diffrent. Instead of rolling with the waves, you hammer down into the waves. I went from the channel to the dam on sat about 3 in the afternoon, i would have turned back in my Southwind, but did 50 MPH in the deck, and it was not bat at all!!!
Ken F
05-10-2006, 04:29 PM
Dan,
Yep that was what amazed me the most about tunnels too- just get on the throttle & speed up! lol
Ken F
502 JET
05-15-2006, 03:12 PM
I figured I would bump this thread up for (bp).It seems he may have some different info about this subject.