3 blade vs. 4 blade props

awritedin

Cadet
Joined
Dec 6, 2008
Messages
8
What are the rasons for getting a 4 blade prop vs. 3 blade?
I have read that a 4 blade will have less steering torque.

Also, if my boat is leaning left from steering torque which way do I turn the trim tab? In the direction of the steering torque or opposite direction of the torque lean?

( some will go away from trimming and yes trim tabs are next when I can afford)
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: 3 blade vs. 4 blade props

Steering torque pulls at the wheel from prop torque. If steering is pulling to port trailing edge of tab goes to port.Pulling starboard tab to starboard.If boat is leaning thats also from prop torque could lean from trimming in too far or motor mounted too low,long shaft on a short transom.Or just plain from prop torque.Sometimes A deep V boat will try to run on one side of the V.
You could try moving weight to the starboard side.Sometimes a boat will absorb water and lean from the weight.You might check the boat at rest.
Check the bottom for distortion especially near the transom.
Generally a 4 blade is to improve low end performance and in certain specific designs push heavy awkward loads.A 3 blade is more for all around performance.
 

180shabah

Rear Admiral
Joined
Mar 26, 2005
Messages
4,995
Re: 3 blade vs. 4 blade props

Click on one of the prop links at the top of this page.

Scroll down, and on the right side will be the propeller help guide. It give a crash course on all aspects of prop design.
 

john from md

Commander
Joined
Apr 13, 2008
Messages
2,184
Re: 3 blade vs. 4 blade props

What kind of boat/motor combo do you have? Do you use the boat for skiing?
These are some of the things that you need let folks know in order to help you out.

Regards,

John
 
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