4 blade prop vibration?

[james yarosz]

Last fall I banged up my 13 by 13 3 blade prop so I bought a 4 blade to replace it.It is a 13 by 12 brass prop.It seems to have a slight vibration but you can't really feel it,it's like you can hear it.Anyone ever have this problem.The boat seems to have a better hole shot.I gained 200 rpm and lost 3 mph top speed.

[TL7]

I dinged mine (13 x 13) and had it repaired. In the meantime I replaced it with a 13 x 12 as well, but a 3 blade. I know exactly what you mean. When pulling up a boarder I hear more of a rattling noise, like it's coming from under the steering wheel. It lasts 3 - 5 seconds and then it's normal. I guess it just creates that much more torque that it vibrates the entire steering column? I do have better holeshot, and I too lost about 3 mph on top end.

[deafgoose]

OJ props are known to vibrate so get an ACME. :)

[gcnettl]

4 blade props cause vibration. 3 blade props cause vibration. 5 blade props cause vibration.

On the other hand, 4 blade props don't cause vibration, 3 blade props dont cause vibration, and 5 blade props dont cause vibration.

The thing is, all props respond to being spun. If your boat would have came with a 4 blade prop, and you dinged it and went to a 3 blade prop, you would notice some vibration. Simply because it is "different" vibration.

[kaneboats]

Well said. It's kind of like ceiling fans.