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post #21 of 31 Old 03-01-2012
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I did this same project with my Tartan 34 over Christmas.

I recommend cutting the coupling. I used a 4" angle grinder and a Bosch oscillating tool to cut through the coupling on top of the keyway and then 180 degrees on the other side. It was messy, but way better than messing with heat and cold approaches for the reasons you noted. I also didn't put a scratch on the shaft. Had it not been for the scoring I found at the stuffing box, I would have easily been able to reuse the shaft. The whole thing took 45 min, tops.

Next, check the clearance between the dripless/stuffing box of your choice and the coupling. If you have an inch to spare, your next coupling could be a split coupling. The advantage is you don't press the shaft onto the coupling. Instead, the coupling has a slot that closes when you bolt it down. The downside is the coupling is about an inch longer.

Should you not have the space for a split coupling, make sure you have a small sledge to seat the shaft onto the coupling. I ended up using a scrap piece of 3" drive shaft to wail it into place. Every time you hit the shaft, the engine moves forward on the mounts and it takes forever. Not a fun project, but it's the only option unless you hoist the engine and slide the pressed coupling/shaft combo back through the packing and stern tube.

While you're in the neighborhood, have a look at your cutlass bearing and strut. A bearing is only $20 and the easiest time to replace it is when the shaft is out. If your strut needs rebedding, as mine did, it's a good time to get it taken care of. On many boats, mine included, the rudder is in the way of removing the shaft and dropping the strut was the only way to get the shaft out, short of hoisting the engine or dropping the rudder.

Finally, if you haven't had enough good advice from your friends yet, consider having a prop shop balance your prop. Mine had significant differences in pitch and diameter. Friends who've had it done say it made a huge difference in vibration and the cost for a 2 blade is only $200-ish.

Have fun...
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post #22 of 31 Old 03-07-2012
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Re: Shaft coupling removal and reinstallation

pschoonveld writes:
>Next, check the clearance between the dripless/stuffing box of your choice and the coupling. If you have an inch to spare, your next coupling could be a split coupling. The advantage is you don't press the shaft onto the coupling. Instead, the coupling has a slot that closes when you bolt it down. The downside is the coupling is about an inch longer.

Downeast: a split coupling was recommended to me by prop shop that mostly works on fishing boats. Makes sense, except I wonder about balance. Other with experience or comments?

Also wondering what necessitated this work? (I have similar work coming up. the flange key sheared on mine, plus strut need re-bedding.)

Charlie Lincoln Cathlamet, WA Islander 28 #108

Last edited by Skipaway; 03-08-2012 at 12:05 AM. Reason: fingers to quick
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post #23 of 31 Old 03-08-2012
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Re: Shaft coupling removal and reinstallation

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pschoonveld writes:
>Next, check the clearance between the dripless/stuffing box of your choice and the coupling. If you have an inch to spare, your next coupling could be a split coupling. The advantage is you don't press the shaft onto the coupling. Instead, the coupling has a slot that closes when you bolt it down. The downside is the coupling is about an inch longer.

Downeast: a split coupling was recommended to me by prop shop that mostly works on fishing boats. Makes sense, except I wonder about balance. Other with experience or comments?

Also wondering what necessitated this work? (I have similar work coming up. the flange key sheared on mine, plus strut need re-bedding.)

Split couplings do not need to be "longer". Buck Algonquin makes one for many engines that is actually shorter and I install a bunch of them. Still need a fit & face but easier install....


This one is for a 1" shaft and a Hurth HBW box..



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Last edited by Maine Sail; 03-08-2012 at 06:10 AM.
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post #24 of 31 Old 03-08-2012 Thread Starter
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Re: Shaft coupling removal and reinstallation

Charlie,

I am removing the shaft to replace an aging cutlass bearing before it causes any problems and to renew the stuffing box coupling hose. Both came with the boat. I don't plan to change to a dripless connection.

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post #25 of 31 Old 03-08-2012 Thread Starter
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Re: Shaft coupling removal and reinstallation

This looks like a good solution to the new coupling from Moyer Marine.

(OREV_14.0_540) Direct drive prop shaft coupling, with split hub (3/4 inch)

The split hub design insures a tight fit between the coupling and prop shaft as well as facilitating removal of the coupling in the future.

Direct drive prop shaft coupling, with split hub (3/4 inch)
Price: $175.00

Any one used one of these?

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post #26 of 31 Old 03-09-2012
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Re: Shaft coupling removal and reinstallation

Don't rely on a grub screw with an indentation in the shaft to stop the shaft from pulling out of the coupling when reversing. I've seen them do that, and come close to sinking the boat, several times. I use a 5/16th bolt right thru the coupling and shaft. On split couplings, the bolts score the shaft by about half the diameter of the bolt.

Brent Swain, Boat designer, Builder, and author of "Origami Metal Boatbuilding"
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post #27 of 31 Old 03-09-2012
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Re: Shaft coupling removal and reinstallation

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Originally Posted by Brent Swain View Post
Don't rely on a grub screw with an indentation in the shaft to stop the shaft from pulling out of the coupling when reversing. I've seen them do that, and come close to sinking the boat, several times. I use a 5/16th bolt right thru the coupling and shaft. On split couplings, the bolts score the shaft by about half the diameter of the bolt.
Another of God's cosmic jokes. If you WANT to remove your coupling, good luck - heat, large hammers, powerful cutters etc. will be required.

If, on the other hand, you DON'T want it to separate, merely putting it in reverse is very possibly all that will be required.

Brent, re: your reference to running a bolt all the way through - could you just drill & tap part way into the shaft or would that cause balance problems? Also, I don't understand your last sentence - "score the shaft...." Can you elaborate?

I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.
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post #28 of 31 Old 03-09-2012
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Re: Shaft coupling removal and reinstallation

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Originally Posted by Maine Sail View Post
Split couplings do not need to be "longer". Buck Algonquin makes one for many engines that is actually shorter and I install a bunch of them. Still need a fit & face but easier install....
I really wish I had known about the split coupling with a shorter length. I can't stress enough how much easier this would have made the install.
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post #29 of 31 Old 03-10-2012
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Re: Shaft coupling removal and reinstallation

The solid coupling is put on and the holes are drilled so half the hole is in the side of the shaft.

Brent Swain, Boat designer, Builder, and author of "Origami Metal Boatbuilding"
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post #30 of 31 Old 03-10-2012
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Re: Shaft coupling removal and reinstallation

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Originally Posted by downeast450 View Post
Charlie,

I am removing the shaft to replace an aging cutlass bearing before it causes any problems and to renew the stuffing box coupling hose. Both came with the boat. I don't plan to change to a dripless connection.

Down
Im doing all that + more; also plan to stick with conventional stuffing. Interesting that you have a 3/4 shaft; mine is 1/2, so fewer options. I dont have much to offer, so Ill follow the thread so as not to hijack.

Charlie Lincoln Cathlamet, WA Islander 28 #108
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