24 to 21..worth it?

I recently purchase my first boat, 2002 ProCraft 180 Combo, with a 150 XR6. We took it out for the first time a couple of weeks ago. It handled "OK" and GPS said we got up to 58 with four adults. I didn't realize the steering would be stiff at high speeds but that's another story. The current prop is a 14 1/4 x 24 SS Turbo. I don't recall what RPM we were running at WOT.

I plugged in the info at the Mercury prop selector and this is what they listed...




Do you think there will be a noticeable increase in performance if I switch to a 21??

Replacing the prop isn't in the budget but if it will make a major difference and if I can find a used one at a good price I might pull the trigger.

Re: 24 to 21..worth it?

Without knowing the current RPM at WOT there's no way to tell.

Re: 24 to 21..worth it?

What he said^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

What you are looking for is to hit the max rpm your motor is listed for with a normal load aboard. 4 adults and gear may be the max load for an 18' boat. If you are propped always to hit max rpm with that load you can over rev with lighter loads....

Re: 24 to 21..worth it?

Yep, that makes sense now. I spent 5 hours reading about props last night! ha ha

I think it's supposed to get close to 70 this weekend so I may go out for a couple hours and see what the RPM's look like.

Thanks