Shaft is shot

[tomgrigsby]

I have a bronze shaft that is corroded and eating up the cutless bearing. She's on the hard for bottom paint and the yard said they will have a stainless replacement fabricated. Going to be pricey I'm sure. I don't have many options here but would like to hear your thoughts. I believe the shaft is a 1" x 50". Any ideas what cost "should" be?

 

[Ralph Johnstone]

Any ideas what cost "should" be?

I would estimate an arm, a leg, and a vital organ, considering I've never purchased one before.

Far more important, is to determine WHY the brass shaft is badly corroded and ensure the same thing doesn't happen to the new shaft and the (most likely) bronze prop.

 

[woodster]

get a quote from general propeller in bradenton fl

 

[Jim Legere]

Most shafts wear at the cutless bearing and at the stuffing box. Make sure that the slits in the cutless are not blocked or painted over, as they let water in for cooling and lubrication. Similarly, the stuffing box should drip a couple of drops a minute when the shaft is turning. And, obviously, a couple of shaft anodes must be in place and replaced as necessary.

I had to replace a bronze shaft after a couple of motor mounts broke in rough weather offshore. I found a used 1" SS shaft that was longer than the old shaft. As I recall, it cost less than $200 to buy it, have it cut down and a new key way machined. I would look around the the yards, on Craigslist or whatever, for a used one one from a scrapped boat. 1" is a pretty common size.

 

[uncledom]

Tom, get a quote here on SBO. I am toying with the idea of replacing mine and they gave me a price of 550ish for a 1 1/4 " shaft. That's with hub and ready and to go.

 

[SFS]

Last october, my 1" shaft from General Propeller in Bradenton was around 500 dollars. Don't remember the length.

 

[tomgrigsby]

Those prices are in mind with what the yard is quoting and that is helpful info. Thanks so much for replies and suggestions.

 

[kito]

I ordered a new SS shaft/coupling for my H30 from the SBO store a couple years ago for around $300. You may ask Phil if he can still get you one. I don't see them listing shafts anymore. They ordered from a place in Florida.
I am kind of curious on what the yard will charge you to have one "fabricated"

 

[tomgrigsby]

I would estimate an arm, a leg, and a vital organ, considering I've never purchased one before.

Far more important, is to determine WHY the brass shaft is badly corroded and ensure the same thing doesn't happen to the new shaft and the (most likely) bronze prop.

The boat had always had a vibration which was else as engine speed increased. I attempted an alignment but didn't improve it and cutless bearing wear was excessive.

 

[tomgrigsby]

The boat had always had a vibration which was worse as engine speed increased. I attempted an alignment but didn't improve it and cutless bearing wear was excessive.

 

[kito]

Have you checked your motor mounts too lately?

 

[Ralph Johnstone]

The boat had always had a vibration which was else as engine speed increased. I attempted an alignment but didn't improve it and cutless bearing wear was excessive.

Sounds like it may have been more of a mechanical problem rather than a corrosion problem. Make sure you've always got at least two anodes on a cleaned section of the new shaft for protection against corrosion.

 

[Maine Sail]

You don't want a SS shaft you want an Aquamet 22 or Aqualoy 22 shaft AQ19 at the bare minimum..

 

[Jim Legere]

You don't want a SS shaft you want an Aquamet 22 or Aqualoy 22 shaft AQ19 at the bare minimum..

I think you have to be careful which stainless steel alloy is used, but 316L or 316N or Duplex are certainly candidates for shafting (certainly in industrial shipbuilding practices). I believe Aquamet and Aqualoy are just proprietary stainless steel alloys, no? Also, monel is excellent for shafts, but expensive.

 

[tomgrigsby]

Have you checked your motor mounts too lately?

They seem to be in decent condition. I'm pretty sure alignment contributed to the problem. When the prop was freewheeling under sail, it would cause the motor to wiggle up and down. Don't know if it was alignment, bent shaft, or both. The boat was repowered with a Yanmar 3GMD at some point, but don't know when. Hopefully this new work will set things right. I'm determined to get good at alignment and intend to run any vibrations to ground now that I'll be starting with a known good shaft.

 

[kito]

My shaft is Aquamet 22 even though I said SS. It is a stainless alloy.