Keep an old bronze prop shaft, or replace?

[preserved_killick]

As part of my cutlass bearing project, and with the stern tube and shaft log out of the way, I was able to get the shaft out of the boat easily. Now that I've cleaned it up I'm wondering if I should I re-use this shaft?



There is some dezincification above the prop taper, but how much is acceptable?


I put the shaft on a machinists granite alignment table and can measure gaps between the shaft and table of less than 4 thousandths of an inch in a couple of spots. These areas appear to be slightly oval rather than bent along the length. I do have a slight bend in the threaded portion right at the last half-inch likely from the prop puller getting the stuck propeller off.


My lovely flexible coupling.

I spent some time researching this bronze/brass dezincification and the whole subject of corrosion and bronze/brass alloys is such a quagmire of information I was not able to come to any conclusions. I think this may be best determined by someone with more experience than I (as usual).

Anyone have any opinions on this? Any reputable prop shops in the Portland Maine seacoast area that might be willing to take a look at this?

[preserved_killick]

One more question: Where is the best place to have a new shaft made up in the New England area? H&H in Salem MA?

-Jeff

[Maine Sail]

I stopped using H&H and switched to New England Propeller. Not that H&H is bad but they are just darn expensive and can have horrible turn around times. Ron at NE Prop does amazing work and trues every shaft that leaves his shop to .001-.002. His prices are better too. I would not personally re-use a shaft that had that much dezincification but I have actually seen them in worse shape, so your call..

http://www.neprop.com/define.htm

Hamilton Marine uses Donovan Marine in Biddeford to do their shafting and they also do good work. They do a lot of USCG shafting and the shafting for Sabre/Back Cove. I am friends with them but they do not have a "front door" and no way to bill a walk in customer so you need to drop off at Hamilton and pick up there too. Their prices are in-line with NE Prop but they don't true every shaft, just check to see that it is within spec..

Be very careful with mail order shafting as I have seen some very, very poor quality work..

[Tim]

H&H is a joke. I have abandoned them forever for reasons that I've documented elsewhere in detail.

I've now used Hamilton for shafting with good results; they'll fit and face your coupling with the shaft if you provide the coupling. Pricing is fair and the turnaround was quick.

NE prop is another good choice. Also consider Accutech in NH and online; I've had good service there for props, though I've not ordered shafting there to date.

My feeling on your shaft, based on what I see, is that it seems a good time to replace it, given the efforts you've undergone to remove all the running hardware at this juncture. That said, it's probably not going to just break in half if you decide to reuse it as is. You have minor scoring visible from the stuffing box, but I've seen much worse. It comes down to your own comfort level, ability and inclination to spend and replace semi-worn components, desire to put things back together once and not have to repeat operations in a few years, etc.

This would also be a great time to get rid of that complicated coupling and replace it along with your shaft...just a thought. With all new components, you'll need not deal with all this stuff again for a long time.

[Maine Sail]

H&H is a joke. I have abandoned them forever for reasons that I've documented elsewhere in detail.

That is exactly how I feel I just did not want to get into it. Glad you said it Tim!

As Tim said, Donovan/ Hamilton is excellent and price is fair. I forgot about Accutech but never used them for shafting so won't make a comment either way they are excellent for prop repair though.

[boatsnh]

4 years ago I had to replace the old "Tobin Bronze" 1 inch shaft on my Dickerson ketch. The shaft was effectively welded to the tranny coupling & had to be cut to remove - i suspect the prior owner never removed the shaft in 30 years. I was going to replace the shaft with bronze, thinking it would be cheaper and present less issues than stainless over it's lifetime - Tobin bronze was used as the "standard" for shafting for years because it was reasonably priced when compared to the "aquamet" style stainless - I found that's not the case now. Stainless is about the same price or less than bronze.

I drove from New Hampshire to Gloucester Ma. to Rose's Marine - right on the harbor. They owns a large repair dock/wharf & marine fuel company - I think it's also listed as "Rose's fuel". I Spoke with "Frankie" Rose - he owns the place. A wonderful experience. Wonderful work - they have a large Machine shop that can make anything - (they had 5 or 6 inch thick shafts being fabricated for one of the ferries on the shop floor) and their pricing is very fair. They do most of the fishing fleet & lot's of "weekend folks" like us. They have trailers full of shafting in stock - turnaround is a couple days. They had new trans coupling on the shelf, in stock. Also had the Gore synthetic Packing - in stock. They have lot's of stuff in stock!

They also bent me a new 1 1/4 inch rudder post on the same visit - the bronze rudder post had bent on a grounding. Frankie examined the existing rudder post, explained why it was not to be trusted (micro cracks) and non-repairable. He then found a new "old" shaft that was in the "used parts" bin - cut it to length Heated it, bent it to shape cut a keyway & squared the top of the shaft for an aux tiller & charged me labor only - for 5 feet of 1 1/4 aquamet shafting....I love these guys!!

After hearing this story, a couple years ago, my brother had them make up a shaft for his Cal 39 - in 2 days - then took it back to Puerto Rico on the plane to install in his Yanmar "repower" - Rose's had the coupling in stock....gotta love it.
Mike

[preserved_killick]

This is just a follow up. The pink on the shaft ended up being just on the surface and fine steel wool was able to polish it off, so I was less worried about the shaft as far as electrolysis is concerned. I did end up making the drive to NE Prop yesterday with my shaft, prop and coupling. I must say that the time Ron spent looking things over and explaining what we have made the trip very worthwhile. He spent 2 hours looking at what I brought in, showing me how things should fit and offering his opinion.

As it turns out, the shaft is in good shape with the exception of some wear where it rides in the cutlass bearing. The shaft constantly measures .8725 diameter down the length of the shaft until you hit the area where the shaft rides in the cutlass bearing - the lowest reading is .8650 ~ a difference of 7.5 thousandths. With the inside diameter of the cutlass bearing @ .8810 there would be a difference of 16 thousandths for play. Whould that cause some vibration? It would seem likely, Ron thinks so, but I'm not convinced that's enough for me to be concerned with.

What he did find is that the prop was over-bored significantly, and poorly done at that. The hub was not drilled evenly, it is stepped inside. And that might be the cause of some vibration. They all thought my prop was odd too. Very think blades, as if it was a 14 or 15 inch prop and was cut down to 12 inches, still maintaining the blade thickness.

At this point, I suspect a new shaft and prop would be nice. I may get a new shaft from Ron at NE prop, and possibly a new prop for next season (2011).

Either way, I was impressed with Ron's willingness to talk. I don't get the feeling he was trying to sell me on a new shaft or prop (although he did push these hefty shaft zincs he's got).

-jeff