3 blade to 4 blade?????

[Genie Aye]

Does anyone know how to stay the same rpm range when going from a 3 blade to a 4 blade??

I have a 15" 19 pitch Stainless Rebel(evinrude)prop now and would like to try a 4 blade stainless for some transom lift and bite.

Any educated guesses on what size to go to??

I do not want to buy a couple props--they ain't not cheap!!

 

[THEFERMANATOR]

A 14 or 13 1/2 X 19 or 18 should get you in the same ballpark. Unfortunately with props it's a guessing game as each one responds a little differently to each hull.

 

[Genie Aye]

A 14 or 13 1/2 X 19 or 18 should get you in the same ballpark. Unfortunately with props it's a guessing game as each one responds a little differently to each hull.

I understand what you are saying--but getting me close helps--no one seems to ever be able to give a straight answer on staying approximatly the same when switching 3 to 4--they all say--try a couple different ones--ya right--a couple thousand dollars can go real quick doing that.

Thanks and keep it coming guys!

 

[reelapeelin]

I understand what you are saying--but getting me close helps--no one seems to ever be able to give a straight answer on staying approximatly the same when switching 3 to 4--they all say--try a couple different ones--ya right--a couple thousand dollars can go real quick doing that.

Thanks and keep it coming guys!

Genie...have you tried these guys?...they don't guess...

www.ptprops.com

Contact them and tell them what's on your mind...

 

[RidgeRunner]

I agree with Reel. The guys that sell props and test props should get you the right one the first time. Ken at Prop Gods in Florida can help. He sent me a prop that I could test before purchase. It arrived new in the box and worked great on my rig so I bought it. If the test prop does not suit you you take the undamaged prop and box it back up and send it back. It costs but not like a new prop. If you like the prop you are not obligated to buy his prop but his prices were reasonable. You may find someone closer to you that offers the same service. Boat yards used to help.

 

[Destroyer]

From the iboats prop selection section:

3 blades... or 4?

We recommend 3-blade propellers for recreational boats with 3, 4, and 6 cylinder outboards and I/0 engines.
These propellers provide good "hole shot" and top-speed performance.

We recommend 4-blade propellers for bass boats and boats with high performance hulls running high horsepower outboard engines.
Compared to 3 blades, they provide better "hole shot" performance with less steering torque and less vibration at high speeds.

When switching from 3 to 4-blades, generally a 1" pitch decrease is required. So, a 21" pitch 3-blade prop is replaced with a 20" pitch 4-blade prop. Pitch is increased when switching from 4 to 3-blades.

Hope this helps a little

 

[THEFERMANATOR]

From the iboats prop selection section:

3 blades... or 4?

We recommend 3-blade propellers for recreational boats with 3, 4, and 6 cylinder outboards and I/0 engines.
These propellers provide good "hole shot" and top-speed performance.

We recommend 4-blade propellers for bass boats and boats with high performance hulls running high horsepower outboard engines.
Compared to 3 blades, they provide better "hole shot" performance with less steering torque and less vibration at high speeds.

When switching from 3 to 4-blades, generally a 1" pitch decrease is required. So, a 21" pitch 3-blade prop is replaced with a 20" pitch 4-blade prop. Pitch is increased when switching from 4 to 3-blades.

Hope this helps a little

Some of this is true today, but 4 blades have come a long way in recent years. If you are running the REBEL that is the equivelant of a MIRAGE which already has alot of sternlift to it. MERCURY makes a 4 blade MIRAGE I believe that you could try, but you would need to drop 1-2 pitch sizes. I still think a good 3 blade is the best all around and a MIRAGE or THUNDERRBOLT would be a good all around prop for a V-20 with a good size outboard. A 4 blade may help you out in the cruise area, but chances are you will lose some top end.

 

[Genie Aye]

I fibbed--it is 15 1/4 x 19 rebel---After talking with you guys--for the money--I will stay with what I got.

It runs good and in the rpm range specified for my motor.

Thanks for the help

 

[macojoe]

Around here the marina let me use a propto try, I went with 3 before I found what I liked, in my V20 it was a 15 1/4 X 15 I lost a hair on the top end but it had power to spare out of the hole, and with the weight ui carry that is what I needed