Worn Prop Shaft

[rhsanborn]

I figured I'd post a photo of my prop shaft as a warning to others. It looks like checking the packing box wasn't a priority for the first 30-ish years of this boats life, or maybe my expectations were too high. Regardless, this is the area where there packing rubbed on the prop shaft. I'll be checking for drips each weekend to make sure I get adequate cooling in the future. The first machine shop I spoke with wanted 200 dollars to repair this, and some lesser wear around the cutlass bearing. I'll be replacing this with a new prop shaft.

[CalebD]

A new shaft should be around $250 plus the work to put it in.
Might as well do they Cutless bearing and shaft log hose while you are at it.
We found similar wear on our old bronze shaft this winter.

[rhsanborn]

CalebD, I found one for 150, stainless, and well within specs for our 18HP Yanmar. I think I will go ahead and take a look at a new shaft log hose. I was planning on keeping old fashioned packing instead of something like PSS for cost reasons.

[arf145]

Make sure the shaft you get is a "name" brand--I believe there are some out there in the shaft world. If I can believe the guys you replaced mine the second time in two years because it was wobbling, the first one was wobbling because it was not good stainless and could not be made straight by the machine shop. Guess there's some cheap junk out there.

[chef2sail]

What are the "name " brands. You should also replace the coupling usually also

Dave

[Maine Sail]

Shafts made by Western Branch Metals are the premium known quality shafts used in the industry. It should be made of Aqualoy/Auamet 22 not 316 SS.. I seriously doubt you can buy the raw AQ 22 stock for $150.00 let alone do all the machining and fit & face a coupling......

[rhsanborn]

I got a quote from Deep Blue Yacht Supply (Propeller Shafts for sale. Buy your Prop Shaft online and save.) and General Propeller (General Propeller Company). My shaft is 7/8 in diameter by 30 3/4 in length. AQ 19 is 150ish and AQ 22 is Just under 200 from either company. They both say AQ 19 is well within specs for my application. The strength difference between 19 and 22 is 50k PSI and 55k PSI per Western Branch Metals (Western Branch Metals: Marine Propeller Shafting). My coupling seems to be in very good condition. No rust, pitting, etc. It looks nearly new. I'm going to send it to whomever I buy the shaft from and have them take a look at it and make a recommendation. I chose the first two companies mostly because their order process is so easy. Henry Smith is here in Michigan, but their website is horrible, and they're a bit far for me to drive.

I'm open to tales of caution on my assumptions though. Most of my assumptions with regards to boats and sailing have been wrong :P

[Maine Sail]

Originally Posted by rhsanborn

I got a quote from Deep Blue Yacht Supply (Propeller Shafts for sale. Buy your Prop Shaft online and save.) and General Propeller (General Propeller Company). My shaft is 7/8 in diameter by 30 3/4 in length. AQ 19 is 150ish and AQ 22 is Just under 200 from either company. They both say AQ 19 is well within specs for my application. The strength difference between 19 and 22 is 50k PSI and 55k PSI per Western Branch Metals (Western Branch Metals: Marine Propeller Shafting). My coupling seems to be in very good condition. No rust, pitting, etc. It looks nearly new. I'm going to send it to whomever I buy the shaft from and have them take a look at it and make a recommendation. I chose the first two companies mostly because their order process is so easy. Henry Smith is here in Michigan, but their website is horrible, and they're a bit far for me to drive.

I'm open to tales of caution on my assumptions though. Most of my assumptions with regards to boats and sailing have been wrong :P

I will make some comments on the last "mail order shaft" one of my customers had to deal with. As shipped it was simply uninstallable.

Suffice it to say that by the time he was done with the local shop fixing the "issues" from the mail order company he was over $150.00 more than what the local shop would have charged to begin with and still had a shaft that was not AQ22, which is more corrosion resistant......

This is what he got:

Non AQ22 shaft (for salt water use AQ22 is more corrosion resistant)
SS key for the prop end (should be a brass key NOT stainless)
Sloppy key fit for the coupling end
Coupling simply slid over the shaft and was unsafe to install
Coupling set screws were not "spotted" into the shaft
None of the keyways were spooned
Coupling was never faced but didn't fit any way so it really did not matter
Shaft was .008" out of true which is well beyond the allowance for ABYC standards
No prop nuts

[rhsanborn]

You're killing me MaineSail :P I'll call Henry Smith, but I'm giving them a hard time about the tripe they call a website. I'll let you all know how it turns out. I took a look at Western Branch Metals and couldn't even figure out how to order a prop shaft from them ... General Prop did ask me to send them my coupler to make sure it married up well with the shaft. They're based out of Bradenton, FL, but I'm not directly familiar with their operation.

[SEMIJim]

We just replaced the prop shaft on Abracadabra. We had our yard do it. There's a lot of things on the boat I'm not afraid to tackle, but, especially being as this required dropping the rudder, this was not one of them. We don't have the final bill yet, but they quoted about $1000 to:

• Drop the rudder (boat had to be in the slings for that)
• Remove prop, old prop shaft, flange and cutlass bearing
• Have new prop shaft made, plus repair/replace/recondition coupling flange, as-needed
• Install new cutlass bearing
• Install new prop shaft
• Install new zinc
• Reinstall prop
• Align engine with prop shaft
• Re-install rudder
• Splash and check alignment
• Adjust reversing gear ("transmission" for you non-A4 sailors .)
• Test

Boat now does over 7 kts on the iron genny, even with some wind on her nose, with the ol' A4 sounding happy as a clam and running at lower RPM than it used to to get us to 6 kts . It was worth it.

Old bronze prop shaft was bent, out-of-round, and exceedingly worn due to misalignment with the engine. Cutlass bearing was shot, too.

Jim