Prop Advice
Submitted by Bradmac73 on Wed, 2026-07-08 09:14
Hi guys
My new engine (150 Merc) had a 4 blade prop, but the mech that fitted suggested a 3 blade would be better for the boat (due to weight balance of boat being reasonably forward due to cuddy).
I currently have the 3 blade 17p off my old motor on it and it was suggested a 15p might be better for fuel economy.
My limited research says that a 3 blade is preferred for WOT and higher speed, 4 blade for mid range and stability under steam. So I'm wondering what people have experienced in changing one way or the other. WOuld I expect a noticible difference between 3 and 4 blade? And between 17p and 15p?
Any info would be greatly appreciated.
Cheers Mac
sunshine
Posts: 2702
Date Joined: 03/03/09
Speak to Just Props in Ozzy Park
Have dealt with them years ago and their advice was spot on
Alan James
Posts: 2308
Date Joined: 30/06/09
Agree
Michael knows his prop stuff
squidvicious1
Posts: 859
Date Joined: 22/07/10
3 blade for the WOT = speed
3 blade for the WOT = speed / 4 blade more stern lift with less top end and more lower planning speed.
Dreamtime
Posts: 665
Date Joined: 21/09/09
Props
You will notice a potentially significant change in hole shot/planning speed and fuel burn from prop to prop. I have 3 different props and will change them over quite regularly to suit different situations in different sea states.
Bit of trial and error finding the perfect prop which can be tricky. The lads at swordfighter marine in wangarra let me take a prop and test it and return and swap for another if i didnt get the results i was looking for, was pretty surprised when they said that was an option! Ask for Myles if you go there, he was very helpfull!