Slightly bent prop shaft

[Cadence]

Originally Posted by sailah

This is a pretty good overview of what needs to be done to check. He has lots of other videos showing how it is actually straightened. At first he didn't want to give away the secrets but has now willingly shown in later videos how it's done

Out of curiosity what is the bed length on your lathe?

[garyfdl]

Originally Posted by vw1961

Is there any way to find out whether it is bent or not? I thought of maybe mounting somehow a measuring gauge to the middle of the shaft and so measure the eccentricity.
As i will be on the hard soon and could easily pull it, is there a good way to find out if it is bent while not mounted? like maybe rolling it against a 100% flat steel plate?

I am thankful for any ideas

If you are in the States, you can by an inexpensive dial indicator from Harbor Freight.

https://www.harborfreight.com/search?q=dial%20indicator

You should be able to get a shaft run-out using that. Check both ends, at the prop and again at the transmission.

If it is bent and you can get the dimensions, I think I have one around here someplace that came off a Hunter. PM me if you're interested.

Any idea how it would have gotten bent?

[vw1961]

- somebody mentioned the prop should never be free spinning because it might damage the gearbox and creates more drag. well i was thaught too to leave it locked while sailing but the manufacturer of my gearbox (yanmar/kanzaki) says it has to spin free otherwise it will be damaged. so just the opposite but they should know and thats what i do.

- how it might got bent:
once (that was quite a beginners mistake) i was anchored in front of a beach, when the onshore wind and waves picked up the anchor began to drag and i had to quickly lift the anchor in order not to become beached. i had the dinghy attached to the stern with a mooring line. of course when i got the anchor up and put the motor in gear to drive off, i saw the line getting shorter and shorter, it had caught in the propeller. i figured my only chance was to go full throttle and fortunately the prop cut through the line. the dinghy went off to the beach but the boat was save...

[sailah]

Originally Posted by Cadence

Out of curiosity what is the bed length on your lathe?

I have a 14x40" Enco Turn Pro personally. I'm not the guy in the video I think his is 8'.

[Cadence]

Originally Posted by sailah

I have a 14x40" Enco Turn Pro personally. I'm not the guy in the video I think his is 8'.

That is one hell of a piece of equipment. does the 40" indicate 20' from center to bed with clearance understood.

[sailah]

Originally Posted by Cadence

That is one hell of a piece of equipment. does the 40" indicate 20' from center to bed with clearance understood.

It's a 14" swing, 40" between centers. There is also a removable gap near the chuck you can remove.

Since this photo I added a Mitutoyo DRO which is just fantastic.

[vw1961]

Just in case anyone is still interested, it turned out do be a worn out cutless bearing.

[Wotname]

^^ thanks for the update - replacing a cutlass bearing is way better than having a bent shaft.