prop question
 

I got my boat back from the pre-season tune up. My prop was bent again. He said it happened while the motor was in reverse. The mechanic said he preferred OJ props to the Acme props that came standard. ( I may have that backwards) He showed me my factory prop and an OJ. The OJ was much thicker on the tips. I ordered an OJ to use as the main prop and will bet the Acme tuned up again. Any thoughts?

Its my understanding that the Acme's are thinner than the OJ's. My prop guy told me this.

I hope the OJ is more durable. The ACME when perfectly pitched and tuned would likely give better performance, but it seems hard to keep tuned.

Ive never had my Acme's get out of tune without some sort of impact. That being said, my experience is it takes less to knock an Acme out of whack, than an OJ. Its a balance between weight and strength.

the bend is slight. One outer edge tip; is bent a little toward the bow instead of the the stern. He said the vibration would take it's toll over time. Like I said. I am getting an OJ and fixing the ACME for a spare.

The mechanic said it was likely done when backing out from the beach and caused by sand.

Just my $0.02, but I prefer ACME over OJ just becasue the ACME will bend. If you do hit something of any real size the ACME, being made of brass, it will bend and take the damage where as the OJ, since it's made of stainless steel might transfer more shock and damage to other potential weak points in the drivetrain. Would you rather replace a $400-500 prop, or spend several thousand to replace prop, prop shaft, v-drive, etc.? That's just my take on it.

I had some damage to my prop last season while hitting a stick when backing off the trailer. It only bent the tip of one blade, but it made a lot of vibration. I took a pair of channel locks and bent most of the damage out and rode the rest of the day. I couldn't have done that with an OJ I bet.

OJ makes ni-bril,(brass) props too. I actyally don't think thyey make stainless inboard props anymore, or haven't for a while for that reason.

Just curious, because I do vibration analysis for a living, did you ever feel/hear an increase in vibration in the boat last year?

The OJ prop I am getting is brass/bronze. It is not stainless. I can't tell any difference in the vibration. The guy is a former CC corporate engine guy and really knows is stuff. He has his own shop and my dealer said take my boat to him. I live 350 miles from my dealer.