Logo
FULL SITE MENU

DiameterPitch how does that translate to MPH

S

stewsbs

Contributing Member
I have a 1986 Bayliner Capri w

I have a 1986 Bayliner Capri w/AQ131A and 275 leg I am running a 15x15 prop and getting 4500 RPM but my speed is only about 25MPH I really want to increase my top end speed any suggestions?
 
"From the little I know a 15x1

"From the little I know a 15x15 should have way more torque and pull you up out of the water faster, but not have much speed up top.

A 15x17 will be a little better, but not great for top end.

I am running a 15x19 looking for top end speed, and am not too worried about popping up skiers as fast.

I have an 86 Bayliner as well with the 275, but don't ask me about my speed yet. I think I have a throttle cable issue."
 
"Even with my cable issue and

"Even with my cable issue and a similar boat to yours I was in the 25-28mph range at only 3,000rpm. I'm sure when i fix my cable and can throttle up to 4,000+ I'll find even more top end speed. I think a 15x19 is what you should try."
 
"Maybe El Pescador could chime

"Maybe El Pescador could chime in, but I think that going from a 14" to a 15" diameter may help with our size and weight of these boats.

It could also be that you have the 131A and I have a 225E."
 
"Ive tried them all so far .I

"Ive tried them all so far .I have no problems with getting the revs,I think the next prop I'll try will be a 15 X 19.that should give me what I want.anyone thats tried this please give me feed back."
 
I know the table as far as cha

I know the table as far as changing pitch but how does changing diameter affect speed and RPM's and how does changing pitch affect speed!
 
"I don't know of a formula

"I don't know of a formula that gives the prop diameter and pitch for the various combinations of hull shapes, hull lengths, engine output etc. I think what you are doing, experimenting with various diameters and pitches and recording the results will eventually get you where you want to be. Many prop shops will allow you to 'test' drive props to arrive at a sale.

fwiw, Tom"
 
Back
Top