Visit our Popular Forums

Shrew · 09-03-2020, 09:42

Is the key deformed? Is the keyway wallowed out?

While in the process of replacing a dripless shaft seal and having a prop repaired, I ended up finding a litany of issues. The key was severely deformed. They keyway on both the shaft and the coupler was wallowed out and someone had drilled the coupler and the shaft to install what looked like 2 set screws, but were actually a workaround/replacement for the key/keyway.

The prop shop condemned the key, coupler and shaft (the shaft was also slightly bent). They wouldn't even attempt to rotate it.

Tmacmi · 09-03-2020, 10:40

Quote:

Originally Posted by Shrew

Is the key deformed? Is the keyway wallowed out?

I don't know yet. I was just happy to get the set screws loose to get the shaft out. Next weekend I take the coupler out.

Then the hole kit and kaboddle goes to the shop I found. Here's hoping that the keyway in the coupler is OK.

Tmacmi · 14-03-2020, 15:15

Well, good news. The rudder came out with a bit of work. (Thank goodness for the strength of two 20 something year olds.

It turns out the shaft is made of bronze? Brass? A quick google says a SS steel replacement is a good thing.

True?

stormalong · 14-03-2020, 15:31

Yes, Aquamet 22 stainless is much stronger and harder than bronze. It would not have worn that way - it would have sheared the set screw first. If you can't find someone locally to do the job talk to Crowley's yacht yard in Chicago. They might do these themselves or at least recommend someone to do the job. You will probably need to send the prop and the coupler to the machine shop to make sure they do it right.

Tmacmi · 16-03-2020, 14:26

Quote:

Originally Posted by stormalong

Yes, Aquamet 22 stainless is much stronger. If you can't find someone locally to do the job talk to Crowley's yacht yard in Chicago.

This weekend was full of discovery and of course one issue leads to another, and another, and another, and.... soon this boat will never get in the water. So here are my questions.

1) The machine shop here sells the Aquamet line of line of shafts. Do I need Aquanet 22? They sell other types of Aquamet, what are the differences? This is a fresh water boat. I don't expect to own it for the next 15 years.

2) I removed the cap from the stuffing box and found swirls in the lip seen below. What is your feedback? Clearly the shaft has run against it. Does it need replacement. What caused it?

3) Its not a great photo but you can see the stuffing box body and hose with a green stripe on it. I am guessing this is a "since you are in there you might as well change it" thing. How hard will it be to cut? What is it connected to on the boat end? Metal? Is Shields 250 sufficient for this application?

Thanks as always.

rbk · 16-03-2020, 14:42

Don't cheap out and re-use your old coupler (sounds like you are from above post). They are cheap and should not be re-used again and again, more so with the ordeal you've been through. Get a new split coupler and have it faced and fitted to the shaft.

stormalong · 16-03-2020, 14:49

The stuffing box is fine. The swirls probably mean that the shaft or the hose was out of alignment. The wear looks insignificant. Use Teflon packing to replace whatever was in there. I have a PSS but people who know always say to use Teflon.

If it were me I would go with the Aquamet 22. The machining costs will be the same so why scrimp on the materials. How much more is it?

Shields 250 is great for this application. That is a light duty for that tough a hose. But if you don't replace the stuffing box just leave the existing hose in place.

DefinitelyMe · 16-03-2020, 14:58

Quote:

Originally Posted by Tmacmi

1) The machine shop here sells the Aquamet line of line of shafts. Do I need Aquanet 22?

2) Does it need replacement? What caused it?

3) How hard will it be to cut? What is it connected to on the boat end? Metal?

These things are always a matter of opinion. For my part:

1) No, but if you can get something decent locally I'd probably go that route myself.

2) It was most likely caused by the fact that your old shaft was bent, so didn't run true. Did it leak? If not then there's no reason it should start leaking now once you've replaced the shaft for one that runs true. I wouldn't replace it myself.

3) I'm not sure what you're considering cutting... The hose? The stuffing box? Half an hour with an angle grinder will tackle most things.......

What's at the boat end? You mean the shaft log perhaps? Could be metal, could be fiberglass. The hose may or may not be sealed onto it with adhesive sealant as well as being hose-clamped. Either way, slicing it off with a knife is usually the best approach I find. But, I probably wouldn't replace it myself.

Tmacmi · 16-03-2020, 15:37

Quote:

Originally Posted by DefinitelyMe

2) It was most likely caused by the fact that your old shaft was bent, so didn't run true. Did it leak?

3) I'm not sure what you're considering cutting... The hose?

I don't know if the stuffing box was leaking. It was giving 4-5 drops per second when running. No water when stopped. I never tried to tighten because I planned on changing the stuffing this year anyway.

I was considering cutting the hose and replacing with the current stuffing box. But as Stormalong suggest maybe I should just leave in place since I am using the same stuffingbox.

Tmacmi · 17-03-2020, 15:51

I dropped the old shaft and coupler with machining company. He showed me inside the coupler and how the key way was mangled along with everything else. I think I'll be out the door right at $500.