kirschdog68 wrote:
When I purchased my boat (1992 sunbird Corsair 185) it has 4.3 OMC
Cobra I/O. I use it mostlyfor skiing and tubing and I am not very
impressed with the power it has and it has a very hard time plaining
it self out. I talked to a local boating shop and he was inquiring as
to what prop I had on it. I checked the prop and it was a 21 pitch and
I think a 14.5 diamiter. At full speed it runs around 3800 to 3900
RPMS. The man at the boat shop said that I should have on a 17 pitch
prop. I am not realy concerned with top speed however I do not want to
go realy slow either, I am pritty much concerned with power for skiing
and such. I think I have pritty much decided on a 15 pitch prop
(unless someone else has any sugestions) and my real question is, when
I go online and look at props for this boat it find three blade and
four blade, aluminum and stainless steel, 14 inch and 15 inch and lots
of other sizes. I would like to keep the cost to a minumim however if
I will get alot more performance out of spending a little more money
then I would rather do that. basicly if some one could help me out
with what pitch prop and what size, number of blades and aluminum or
stainless, it would be a big help. Thank you in advance


It's not an exact science. We have all been there. You should prop
your boat so you can reach maximum RPM's even in you don't need to run
that fast. For a quicker hole shot, you can look into venting your prop
- getting small holes drilled at the base.

Stainless has slightly less flex than aluminum and the blades are often
slightly thinner.

Find a prop shop in your area. They can change the pitch and add a cup
to an existing prop.