shaft coupling

[alcodiesel]

So I'm investigating the drip rate on the stuffing box (too fast) and I turn the stuffing box and discover there is play in the shaft to coupling connection. The lock nuts are wired. Go ahead and tell me the bad news.

[ndutton]

You need to determine which is the offending component, shaft or coupler, and replace as indicated. The full Monty is replace both. Good time for a MMI split coupler.

Do it right, cry once.

[alcodiesel]

Thank you. Yep, Neil, that's about what I am thinking. Now we're talking an unplanned dry dock . And the shaft is unbelievably difficult to get to.
I only use the iron sail in and out of the marina. 20 mins and I don't push it. I've been waiting all summer for the wind to return and it's just coming back now. I'd like to do this when the wind gets poopy again, June, July.
Will tightening the 2 wired bolts on the coupler, if loose, help?

[ndutton]

Originally Posted by alcodiesel

Will tightening the 2 wired bolts on the coupler, if loose, help?

Yeah, you'd better tighten them up or your shaft could slip out in reverse.

[Al Schober]

Torque is transferred from the coupling to the shaft by a key. Thrust loads fore/aft are transferred by the set screws. It's important that the set screws seat into drilled recesses in the shaft, otherwise it's easy for things to get loose. And if they get loose the prop and shaft can slide aft out of the coupling.
Navy practice is to add some pieces to the coupling. The shaft gets a groove machined in it a bit back from the front end. The coupling goes on past the groove, then a pair of half-circle plates fit into the shaft groove. It all gets bolted up to the next piece forward.
If the shaft pulls out of the coupling, it isn't good. If it just pulls aft a little, you lose propulsion. If it pulls aft a lot (like through the stuffing box) you could lose the boat.

[alcodiesel]

Ok, I got the bolts tight. Thanks to Blaster getting them loose. Now there is no play in the coupler to shaft joint. I have a pull out scheduled January 17. Looking to replace the coupler, shaft, stuffing box, log, possibly the cutless (or cutlass- I've seen lately)

[joe_db]

Originally Posted by alcodiesel

Ok, I got the bolts tight. Thanks to Blaster getting them loose. Now there is no play in the coupler to shaft joint. I have a pull out scheduled January 17. Looking to replace the coupler, shaft, stuffing box, log, possibly the cutless (or cutlass- I've seen lately)

Cuts Less - Cutless
Cutlass is a sword

[ndutton]

I wouldn't get too wrapped around the axle on this. Regardless of pedigree, "Cutless" and "Cutlass" for the names of our shaft bearings have both been commonly accepted at least as far back as I was purchasing them at Islander Yachts, nearly 5 decades ago.

[Sam]

Off topic but I have to make a comment on Islander boats. Elderly gentleman in his 80's, strong physically but forgetful on a can next to mine has a 64 Islander 32 that had not moved all summer - reason "couldn't get A4 engine started". I got involved in Oct and was overwhelmed by the toughness of the boat - small cabin, built like a tank with the A4 sitting at the bottom of the companionway - takes up cabin space but the BEST access ever all around. Thx to Moyer parts no/weak spark was solved by new rotor/coil/wires and fuel delivery with new fuel pump and idle passage carb cleaning all done with ease. [He had EI but did not know he had it] He was then able to motor/sail about 15 miles to winter layup. Very envious of the engine access.

[Al Schober]

Not sure why you're replacing all that stuff. Does it need replacement?
Make sure whoever is doing the shaft has the coupling in hand so they can drill the shaft for the coupling set screws. They can also face the coupling so it's running square to the shaft.
DO NOT tighten the set screws against a smooth shaft and expect them to keep the shaft secure.

[msmith10]

As Al said, squaring off the facing of the coupling is very important and I think often overlooked. You'll never be able to align it properly if the face isn't square to the shaft.

[tenders]

Bill/alcodiesel, what’s your shaft diameter? I have a 3/4” split coupling around here somewhere that I intended to use on my 32 but that is incompatible with my vee drive. Not too many 3/4” shafts out there but if your 27 is one of them I might be able to make you an offer you won’t want to refuse.

[alcodiesel]

Thank you.

All the other stuff came with the boat and all is of unknown age. Years ago I made this my last boat so putting $ into her gives me no heartburn- she's staying in the family.

The cutless replacement is a maybe. I detect strange sounds coming from that area when in gear.

I want a dripless put in and

I think best practice is replace the coupling and shaft.

As for the log- Original? I want to make a determination on all.

I believe the engine has to come out due to very limited access.

Technically I can do all this BUT my physical condition limits this to near zero possibility. I'm gonna have this professionally done and I will have a say in all steps (which might cost more-haha). That's what the haul out in January is all about.

[alcodiesel]

Guess what Tenders- it's a 3/4"
Let's Make a Deal.

[tenders]

I am out of town this weekend but will embark on a Quest to find the coupling.

[alcodiesel]

If y'all would educate me:

1. why do I want a split coupler?

2 why do I want a dripless stuffing box?

I think I know- I want confirmation or not

Thank you fellers

[ndutton]

Addressing #2, these three posts are from the same thread 8½ years ago:
https://www.moyermarineforum.com/for...62&postcount=6
followed by
https://www.moyermarineforum.com/for...66&postcount=7
and finally
https://www.moyermarineforum.com/for...1&postcount=10

[joe_db]

Originally Posted by alcodiesel

If y'all would educate me:

1. why do I want a split coupler?

2 why do I want a dripless stuffing box?

I think I know- I want confirmation or not

Thank you fellers

1. why do I want a split coupler?
Because they are easier to work with. I always suggested my customers get them back when I did that kind of work.

2 why do I want a dripless stuffing box?
Because they don't drip! The case for them may not be as strong now as it was before Teflon packing came out, I have never tried that. I have had one since about 1985 or so and like it.

[alcodiesel]

Ok so maybe I don't want a dripless.
What about the split coupler?

[ndutton]

I have no experience with the split coupler so I have no business commenting on it. However, my experience and opinion of the standard coupler is this: In the 100+ engines and drivelines I installed in the 1970's during my employment in the sailboat industry I never installed a shaft by beating it into the coupler. The current practice of a fit so tight it needs a hammer for installation is bad form in my opinion. I think it was MMI forum member Al Schober who said the keyway holds the torque, the set screws hold the thrust or something to that effect and I endorse the assessment wholeheartedly. I would even add to it that the coupler holds the alignment. Such a tight fit risks hammer damage to the transmission internals too.

On the bench I would dress the inboard shaft ends with a hand file carefully until the coupler could be slipped on by hand. With it in place and the set screws removed from the coupler I would mark dimple locations on the shaft, remove the coupler and drill generous dimples into the shaft on a drill press. Final assembly would be to slide the shaft into the the coupler (mounted on the engine) until the dimples were visible in the set screw holes, install and tighten the set screws and secure them with seizing wire.

Never a problem and as I said earlier, hundreds of boats.

[Al Schober]

NO, do not 'dress' the end of the shaft to fit the coupling! The coupling is made out of cast iron and will corrode. The shaft is stainless or perhaps bronze - stable materials. The reason the fit is tight is that the bore of the coupling has corroded.
I recommend you get a dowel about 1/8" smaller than your shaft, wrap some 80 grit around it, then clean up the inside of the coupling. It won't take much work as you're removing rust, not good metal.
Again, you need the drill recess in the shaft to take the cup point of the set screw. Measure the cup point and you'll know what size drill to use. I recommend a cobalt drill for cutting stainless - HSS will just burn. I also recommend a drill press!

[alcodiesel]

Can we circle back to dripless for a minute?

I failed to mention access to the stuffing box to adjust the packing, for instance, is very difficult if not impossible (for me) with the engine in place.

Thoughts?

[joe_db]

Originally Posted by alcodiesel

Can we circle back to dripless for a minute?

I failed to mention access to the stuffing box to adjust the packing, for instance, is very difficult if not impossible (for me) with the engine in place.

Thoughts?

I love mine! It has been not leaking for over 35 years
* well actually I am on #2, about 8 years ago I got a new shaft and replaced it while everything was apart.

Whenever we ordered a shaft and coupling that was not a split coupling we had the prop shop fit the shaft and coupling for us, they made sure it wasn't too loose or too tight. The split couplings are so much easier to get on and off we always tried and use them.

[Al Schober]

IMHO, the face type seals are good. Our Navy uses them on submarines which see considerably more severe service than our boats. But, two things to consider.
First, they like clean water. Silt or grit in the water will wear them out. Navy addresses this by pumping filtered sea water into the shaft tube aft of the seal. I would recommend doing the same. Just tap into the output of the raw water pump, filter it, and run it to the seal. I believe most of the face seal units have a fitting for this.
Second, the rotating part of the seal is held in place by the shaft and is spring loaded against the fixed part. If the shaft moves forward, the seal faces will open up and allow water (a LOT) into the boat. This can happen if your engine is on resilient mounts and they're not up to resisting full thrust. So after installation, give the engine a good push and see what happens.

[sastanley]

To each his own...I have the graphite packing in my traditional stuffing box, and it is almost dripless. I would personally be worried about rubber bellows and burpers and stuff in an area I can't readily access. The amount of sea water that drips in thru the stuffing box almost evaporates before I can sponge it out of the bilge.