87' Seaswirl 16' With a 2.3L 120 HP OMC Cobra - Prop?

[Fenner 45]

I bought this boat 2 years ago as a project. looks and runs great. I am trying to increase performance with a new SS prop. I do not know what pitch is on the current aluminum prop. currently I am running 34 MPH @ 5200 RPM. I have trouble coming out of the hole with more then 2 adults in the boat. I added a hydro-foil to the out drive to help lift the stern. The hydro-foil helped alot. I am now looking for the right prop. I have found an Apollo 13 1/4" x 15. I am being told this will make a HUGE difference in coming out of the hole, as well as top end speed. MAX WOT is 5600 RPM.
I use this boat for Pulling/Playing & Fishing.


Please Advise...

 

[Bondo]

I do not know what pitch is on the current aluminum prop. currently I am running 34 MPH @ 5200 RPM.

Ayuh,.... So pull it off, 'n find the numbers on it,.... It's Important info,....

 

[steelespike]

You may find the numbers near the base of the blades or under the prop nut.
If we guess the slip and run it through the calculator solve for prop we get 15.69. Lets call it a 16.
Guessing the input numbers is a real crap shoot so you really need to look for those prop numbers.
Also original tachs are always suspect. So we are calculating with 2 major numbers slip and rpm that are suspect.
A 15 or 16" prop is a reasonable start.
I don't know how anyone could know the results with the 15" apollo when we don't know what your running for sure.
While a ss prop can improve overall performance if your running a good al15 and you replace it with a 15 stainless
you may actually lose some performance because the ss will load the motor more than the al 15.
If it turns out your running a 16 or 17 any good 15 would improve your hole shot.
An al 4 blade will improve hole shot,stay on plane better at reduced throttle,run smoother and respond better around the dock.
Based on your rpm you would reduce pitch 2". 4 blade may cost a little top end.But will make things much easier for your motor.
It can do all this for 1/2 to 1/3 the cost of stainless.