2 & 3 blade prop difference

[Matt1214]

i have a prop with 3 blades on my little 7.5 mercury. if i buy a 2 blade prop what is the difference? will it cause the motor to steer harder/easier? is a 3 blade better than a 2 blade for that size of motor?

Also the 3 blade has a chip off one of the blades about 1-2 inch of the blade is missing on the end. how must do you reckon a fair price would be to fix that at a local marine?

thanks for the help

 

[steelespike]

Re: 2 & 3 blade prop difference

I'm a little on the outside of prop technology but::
What is the size of the prop?do you know if the 3 blade is typical for that motor?
Originally theoretically a 1 blade prop would perform best but obviously
there is a balance issue.The next best would be a 2 blade but with todays techonolgy the 3 blade is pretty univeresal and you may see 4 and 5 blade props for some applications.Generally as you add blades it increases resistance but for certain applications it doesn't enter into the equation.
Prop technology is more likely to affect steering than the number of blades.
Identical props from different manufacturers can produce different results.
2 blade might perform better than 3 or vice versa.In my opinion
a 3 blade would do better in certain heavy load setups hole shot for instance.
Some 4 blades are made specifically for heavy hard to push boats.
All that said you prtobably wouldn't notice the difference with a properly sized 2 or 3 blade prop.

 

[HAV2FISH]

Re: 2 & 3 blade prop difference

I would stay with a 3-blade prop. It will give you better performance. I would also get it fixed before using it again. Props are balanced and with a ? chip out of one blade your way out of balance, that?s hard on the gears in the lower unit. Having it fixed should only cost about $75 if its an aluminum prop, $150 if its stainless.