Prop to Rudder Clearance

[kvand347]

I put my new 4-blade prop on yesterday and I only had about 1/4" from the prop blade to rudder. My 3 blade is about 1/2". I did not feel comfortable enough with that spacing to keep the 4 blade on so I took it off and used the 3 blade. I could not get the 4 blade any further up the shaft.

Your thoughts?

[kvand347]

Anyone? I'd like to figure this out before I go boating this afternoon...

[docdrs]

There should be no play in your drive line fore/aft and there will only be flattening deflection away from the rudder while if forward so you should be fine. If you spin it hard in reverse there could but doubtful be a concern. As long as your motor mounts and tranny driveline are solid. just my .02which may not be worth much

[docdrs]

Oh you could take the prop to a machine shop and have them enlarge the front of the prop hole slightly so it will slide up further. Prob only have to do a 1/32 - 1/16 on the first inch of the prop shaft hole to get it to slide up further.

[kvand347]

Thank you very much Doug! I was really hoping you would chime in. I agree with you that as long as there is no fore/aft play then it should be fine...it just made me nervous it was so close! You are also right that when hammering down in forward that the prop will deflect away from the rudder. I don't know if you could spin it fast enough in reverse for it to deflect and affect the rudder.

I will try lapping the prop to the shaft with some valve grinding compound. That might bring it further up on the shaft too. If not, at least I know that it will be seated properly!

Thanks again!!

[kvand347]

Took it out this afternoon and no issues with it hitting the rudder. I'm still pretty nervous about it and may pull it off and have it machined. It is way too close for comfort. I'll go take a picture so you guys can see what I mean.

[kvand347]

Note: The chip in the rudder was there before I installed the new prop.

[Jetlink]

Looks like a well placed chip, almost strategic if you ask me...

[docdrs]

Even easier would be to grind the rudder back in this area, I doubt it would impact steering or performance

[lively]

Even easier would be to grind the rudder back in this area, I doubt it would impact steering or performance

use a sawzaw!!! lol