Props what effect does diameter have?

[Coddy]

Hi guys

 

I have a question about props which I am unsure of.

 

I know my boat prop is over pitched, I suspect I need a 15x15, currently running a 15x19 BUT what differance does a change to the diameter make?

 

I am looking at a 16x13, what effect will this prop have?

 

The boat has and inboard engine on a volvo outdrive.

 

Dave

[oysterboats]

im pretty sure changing the size of the prop will alter the rev range lowering the diameter increases the revs and increasing the diameter lowers the revs im open for correction if im wrong tho

[Coddy]

Hi Graham

 

That was what I thought, however if you increase the diameter but reduce the pitch does the revs stay the same?

 

Will it be slower on acceleration or quicker?

 

Questions, questions

 

Dave

[Member Removed]

A lot.

Give us a ring on 01258 858784, speak to Thomas.

Propeller Solutions.

[oysterboats]

best to give propsol a call. as far as im aware if you increase the diameter and reduce the pitch the revs should change ie 15x15 prop on a 270 leg with a 2.3 sierra engine giving 67hp with a 2.15 reduction was revving to 4200 and changing it to a 15x17 dropped the revs to 3200 and increased the speed by a knot we can all have our own ideas about things but sometimes it is best to seek help from the experts .