2 bladed prop to 3 blades

[roger3645]

I'm running a 1975 merc 85 hp (Still runs good) it has a 19 pitch 2 bladed prop. I want to change it to a 3 bladed prop. I read somewhere when adding an additional blade you should drop the pitch down. If so, I should drop down to a 17 pitch prop. Does this sound right to anyone else?

 

[JB]

Re: 2 bladed prop to 3 blades

Prop topic

 

[LubeDude]

Re: 2 bladed prop to 3 blades

Yes, thats right, providing you stay with the same diameter. Also, your two blade may not be cupped, most two blades Ive seen are not. Go ahead and try a 17P. Be advised though that props are kinda like a pair of shoes. Even two of the same props may not perform the very same.<br /><br />What are you trying to achive?

 

[roger3645]

Re: 2 bladed prop to 3 blades

It's my understanding that a 2 bladed prop causes more lower unit vibration than a prob with three blades. Just trying to nip any future problems. I've had to replace my lower unit once.