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Mercury 90hp CT 15 pitch 3 blade

S

Stephen Graham

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20S with 2 toons, lifting strakes. 90hp CT, 3 blade SS 15 pitch. We consistently get 32 to 34mph. Water and weather just right we have seen 37mph.
 
Color me impressed! I would have never suspected a 90 could spin a 15P Ss that fast. Post some pictures of of your Benny.
 
Michiman said:
Color me impressed! I would have never suspected a 90 could spin a 15P Ss that fast. Post some pictures of of your Benny.
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Same here.
 
What is "CT"?
 
Stephen Graham said:
Command Thrust
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My understanding is a 90hp CT has a 150hp lower unit and gear box. Giving you a much wider range of prop pitch and size. I have also read lifting strakes won't help till your up to 150hp or more. I've read alot about pontoon boats in the last 5 years. So far I'm still not convinced it's a perfect science. You want to know what I boat will and won't do. Take a test drive. I have owned ALOT boats in the last 40+ years. I'm convinced the dealers know just about as much as "you" do. ymmv of course.
 
Stephen Graham said:
My understanding is a 90hp CT has a 150hp lower unit and gear box. Giving you a much wider range of prop pitch and size. I have also read lifting strakes won't help till your up to 150hp or more. I've read alot about pontoon boats in the last 5 years. So far I'm still not convinced it's a perfect science. You want to know what I boat will and won't do. Take a test drive. I have owned ALOT boats in the last 40+ years. I'm convinced the dealers know just about as much as "you" do. ymmv of course.
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Interesting info. Out of curiosity, do you have normal twin pontoons, or Elliptical dual pontoons?
 
When the boat was new, before the lifting strakes. Basic boat. 20S cruise model. I added hydraulic steering, the strakes, duel batteries with a switch. SS prop. Otherwise as it came from the factory. I'm 230lbs. Can ski behind this boat. Tube 2 kids with 4 or 5 people in the boat. Of course with 10 people in the boat it becomes a let's watch the fireworks boat. I'm well pleased. I just never buy high-end $$$ boats. Not that there is anything wrong with that....but I mean it's a "boat". I use my boat alot and still 15x a year maybe? When you divide the price of very a expensive boat x the times you use it year = a very expensive per ride $$ amount. Cheaper to rent one.
IMG_20200408_151101051.jpgIMG_20200408_150109749_HDR.jpg
 
She’s a beauty! Enjoy…
 
Stephen Graham said:
My understanding is a 90hp CT has a 150hp lower unit and gear box. Giving you a much wider range of prop pitch and size. I have also read lifting strakes won't help till your up to 150hp or more. I've read alot about pontoon boats in the last 5 years. So far I'm still not convinced it's a perfect science. You want to know what I boat will and won't do. Take a test drive. I have owned ALOT boats in the last 40+ years. I'm convinced the dealers know just about as much as "you" do. ymmv of course.
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Could you tell me your engine speed when your outstanding boat speed was achieved? I agree with you with regard to boat speed - it is more art than science. I struggle to make sense of what I hear from the so called prop experts. Only one expert asked me enough questions in order to calculate propeller slip on my current setup. Your lower unit allows you to turn a big prop at slower speed. That should give you a better slip number. I am wondering if that would account for your unbelievable speed. Could you tell me both your max boat speed and associated engine speed? Also is there anything special about the lifting strakes that you added? I am hoping to learn from your experience.
 
DVW said:
Could you tell me your engine speed when your outstanding boat speed was achieved? I agree with you with regard to boat speed - it is more art than science. I struggle to make sense of what I hear from the so called prop experts. Only one expert asked me enough questions in order to calculate propeller slip on my current setup. Your lower unit allows you to turn a big prop at slower speed. That should give you a better slip number. I am wondering if that would account for your unbelievable speed. Could you tell me both your max boat speed and associated engine speed? Also is there anything special about the lifting strakes that you added? I am hoping to learn from your experience.
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"Michelle" at Powertech is the engineer that set me up with the SS prop I have on the boat. I took the boat around to the dealer by water yesterday. Was by myself. Full tank of gas. Windy, a little choppy. 5400RPM. Trim up 1/4 of the gauge. Per GPS 32/33 mph. Because of the wind and chop I didn't bring it up to WOT. When the boat was new (2020 model)both pontoons leaked. Dealer tried to repair made a really big mess(long story). Bennington stepped in and replaced both pontoons. I had factory lifting strakes put on the 2nd set. 6inch. Inside and out. SS prop was put on at the same time so can't say which did what, but the speed shot up like a rocket when it went back in the water. I pass tritoons on a regular basis 150hp and more. They look at us like wth? Everything adds weight. 22ft weighs more. 3rd log weighs more. 150hp weighs more. Believe me nobody is more surprised then me at this performance..
 
Powertech has propped out several shall we say "troublesome" boats over the years. Need to know what pitch your running and GPS speed at WOT to even get started. It may take 1 to 3 tries before you get the right prop.
 
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