4 blade 18 pitch vs 3 blade 19 pitch

[joedesigner]

I'm running the 4.3l V6 in a 2005 Trophy 2052 WA and recently decided I wanted a spare prop in my boat, while in for a Spring tune-up I spoke with the manager at the shop about my plans to fish the waters off of Vancouver Island and thought it would be a good idea to have a spare prop the wrench and whatever else I would need to replace a prop if need be, long story short he had me go with a new 4 blade 18 pitch from the 3 blade 19 he said I'd notice a big difference in the outta the hole performance. I have not noticed any improvement in fact it seems to lag a bit longer before getting the boat on plane. Any info or advice would be greatly appreciated.

 

[sethjon]

Re: 4 blade 18 pitch vs 3 blade 19 pitch

The difference should be slight but if anything the hole shot should be a little better.

 

[joedesigner]

Re: 4 blade 18 pitch vs 3 blade 19 pitch

Thanks for the response!!! sethjon

 

[SRC8778]

Re: 4 blade 18 pitch vs 3 blade 19 pitch

First off, I don't have any personal experience with 4 blade props so I am only throwing out thoughts, not experience.

Going from a 19 pitch to an 18 pitch is effectively lowering your "gearing" which should help with getting the boat up on plane quickly. Changing from three blades to four should reduce prop slip since you have a greater surface area pushing against the water. With a heavy boat, I could easily see this causing the motor to experience a greater load, dropping the rpms and not letting it make power, when trying to accelerate onto plane. This would be like taking off in a standard shift car without slipping the clutch enough. In my opinion, this why you are seeing a drop in performance. My guess is once on plane though, it performs pretty well and the biggest difference is in trying to get on plane.

 

[Oldskool]

Re: 4 blade 18 pitch vs 3 blade 19 pitch

Typically you are going to see a faster hole shot, be capable of staying on plane as a lower RPM/speed. You may also lose a couple of mph. I recently went from a 3 blade SS Power Tech 19 pitch to an aluminum 4 blade 18 pitch. I may have lost 2 mph total, but I did in fact improve my hole shot, and can stay on plane at about 300 less rpm.

 

[joedesigner]

Re: 4 blade 18 pitch vs 3 blade 19 pitch

Thanks guys I have noticed the being able to stay on plane at lower rpms aspect, actually kind of nice in medium rough seas, I thought. I'm just not feeling the difference at all in the hole shot. My trim tabs are usually both in the down most positions maybe I need to play around with that a bit.