Which prop is right - revisited

[imported_boatin clan]

We just bought a 1988 19' Sea Ray bowrider with a Mercruiser 4.3LX and Alpha I drive.

The prop that came with the boat is a 4 blade aluminum 19 pitch. The current prop, when the boat is fully loaded, may be too much. Last time I went out with 5 adults and 2 kids total - best I could do was approx 3400 RPM at WOT. Took a long time to plane out, too.

What would you recommend for best all around performance, hole shot, quick to plane, etc?

 

[Crownie2]

Re: Which prop is right - revisited

Seems as though the 19" should not be too far off.

Can you tell us the drive gear ratio? It should be on the port side of the drive near the top.

Could be other things holding you back.

Bob

 

[imported_boatin clan]

Re: Which prop is right - revisited

Hi Bob, Is the gear ratio on a label or is it stamped into the drive? I'll see if I can find it and advise.

 

[walleyehed]

Re: Which prop is right - revisited

I have a Wellcraft with a 350 (19ft) and a 19P is a good ski prop and 21 for cruise.
I set my Brother-in-laws boat up with a 19P..It's a 19.5ft Crownline bow-rider with a 350 and alpha1.
I think you might be a bit steep, but I believe your ratio is 1.62:1, so Crownie may be on to something else...
Engine health perhaps....

 

[imported_boatin clan]

Re: Which prop is right - revisited

Bob and Kenny, my gear ratio is 1.84:1

 

[walleyehed]

Re: Which prop is right - revisited

Do you have any reference to speed?
if the tach is right, it's moving around 29mph.
we really need some sort of speed reading to figure slip, and this "may" tell if it's a prop issue or engine issue.

 

[imported_boatin clan]

Re: Which prop is right - revisited

I'll have to take it out again. My pitot was clogged (fixed now) so I had no speedo. I'll check in when I get the boat back out.