3 vs 4 blade props

[mxz]

I am looking for a prop for my sons Voodoo and have it narrowed down to either a 10.375 x 18" Mercury chopper or a Ron Hill 4 blade semi cleaver through hub that is 11.25" diameter. My question is if going to a 4 blade do you have to pitch down at all? Say to a 16"?
Thanks

[David]

I would think 18 in a 4 blade would work.

Bigger diameter and 4 blades will both hold the rpm down. But 60 on a VooDoo should be mid 50s ore more.

[Karsten]

I changed from the 3 blade prop that same with the 2011 Merc 150 Optimax to a 4 blade 20P and a huge improvement, this year and half way through the previous season I upped it to 22P and again more improvement.....next year I hope to try out the 23 P MI Wheel Ballistic I have sitting in the shop.

Karsten

[dgscroggs]

I had a Ron hill 4 blade semi cleaver on a little 12' boat with a 60 merc, I believe It was a 17 pitch I could only spin it to like 3500 Rpms I had to go to a 3 blade

[mxz]

You lost over 2000rpm with just going to a 4 blade? Strange... David, goal is mid 50's which should be pretty easy. An 18" Mercury chopper would be ideal but so far have not had any luck locating a used one for sale. I was thinking of ordering a new 18" Merc chopper but have been told they don't perform as well as the old ones for some reason.

[David]

There are some cleavers in your size range on HPBC. You could buy now and sell what doesn't work in the spring. With a light load a cleaver could work.

[mxz]

I am not sure a cleaver would be the best choice for a lake boat. I have been told by quite a few people that the solid hub is pretty hard on the gearcase when shifting on the small motors. I am pretty sure the seller of those few cleavers on HPBC is in Europe. Also while half of my sons boating is by himself, the other half he has friends in the boat and they are not getting any smaller!

[phillnjack]

what year is the merc 60 and what mods done to it ?

[V-bottom]

I still have one of the older 18 pitch 3 blade chopper that you are referring to. We ran it on my son's voodoo almost 15 years ago that had a 4 cyl. 40 hp merc. It ran somewhere around 53-55mph( by speedo - no gps then) and the boat sat up nice on the pad with that prop. Your 60 should have a stronger hole shot than the 40. You are welcome to try it if you want to come up to Barrie in the spring to see how it performs on your setup....just not sure I want to sell it.

An 18" Mercury chopper would be ideal but so far have not had any luck locating a used one for sale. I was thinking of ordering a new 18" Merc chopper but have been told they don't perform as well as the old ones for some reason.

[hsbob]

the 4 blade may add too much transom lift. at hi speed you'll loose steering without some transom in the water. i had the issue with a 15' vamp doing 72 mph.

[mxz]

I still have one of the older 18 pitch 3 blade chopper that you are referring to. We ran it on my son's voodoo almost 15 years ago that had a 4 cyl. 40 hp merc. It ran somewhere around 53-55mph( by speedo - no gps then) and the boat sat up nice on the pad with that prop. Your 60 should have a stronger hole shot than the 40. You are welcome to try it if you want to come up to Barrie in the spring to see how it performs on your setup....just not sure I want to sell it.

Good info on the chopper, 55mph is our goal and should be easily achievable. Thanks for the offer to try the prop, I think we have found an original 18" chopper for sale.