how is the shaft alignment check done

[Atlasway]

Is it possible to check shaft alignment with boat in the water?
Next question is "how is this done?" I've never aligned a shaft before

[boatpoker]

On a 1997 Ebbtide 2300 ???

[Pandor]

Originally Posted by Atlasway

Is it possible to check shaft alignment with boat in the water?
Next question is "how is this done?" I've never aligned a shaft before

Not just possible, but a full alignment can only be performed in-water. If on the hard, you can certainly do a rough alignment. But because the shape of the hull may change when supported by water, final alignment needs to take place only after you are splashed.

Here is a link to a thorough article on a meticulous way to align:

http://www.marinegears.com/pdf/GetInLine.pdf

But as stated in the article, the customary method is just to loosen/ remove the coupling bolts and poke around with a feeler gauge. I doubt many go to the lengths described unless trying to diagnose a recurring vibration problem.

[MicHughV]

This is the way I do it....with the boat hauled out.
I cut a small sliver off the cutlass bearing....about 1/8" wide....
This sliver I insert on the other inward side of the stuffing tube.
Next I slide the shaft in, this assures me, within reason, that the shaft is aligned centrally within the stuffing box. Then I attach the shaft coupler, and try to mate this with the engine coupler to within a few thou of an inch.
Once the boat is splashed, I will check these clearances again.

To do this in the water is a bit more tricky as there is no telling if the cutlass bearing is worn, if it was correctly aligned before, or even if the shaft is worn, etc.

But there is a way, it will require patience and the ability to make a few wood and plywood supports.

First things first though, and you will have to dive on the prop, or have someone do this for you, to determine if the shaft is still tight in it's cutlass bearing. If it isn't, you have a haulout in your future....then see above...

As mentioned above, there is a way, within reason, but again, this is dependent on your DIY abilities, to do this in the water, so I'm not going to detail it here.

[wholybee]

To align the shaft it needs to be done in multiple dimensions. Not only aligned up/down left/right, but also mating exactly flat to the coupler.

Once the up/down left/right part is done (which is the easier part) this is what I do. Not as exhaustive as the link posted, but does well enough.

Bring the coupler halves together. Insert one bolt, finger tight. On the opposite side (but not on a bolt hole) place a .003 inch feeler gauge(removed from the tool, so it is just the metal slip). Tighten the bolt, just past finger tight. Rotate the shaft, and every 90 degrees, try and remove the gauge. If it comes out, the alignment is off, adjust the engine so it won't come out in any position. Then, move the bolt to the next hole and repeat.

All done, separate the shaft and rotate the halves 180 degrees from each other, and check again. If the second check is off while the first was good, then the shaft is bent, or a coupling face isn't square. That is where the longer more exhaustive procedure comes in, but at that point I either except is as good as it will get, or I take the parts to a machine shop for truing up.

[Kello]

Shaft alignment can only be (correctly) done with the boat in the water. If your boat was hauled out, let it "relax" in the water for a day or two. The best instructions I have found are in Nigel Calder's "Boatowner's Mechanical and Electrical Manual" (I have the third edition, instructions start on p. 438) Not only are the instructions easy to understand and follow, there are actual photographs.

You will need to lift your engine off its mounts to move it around, depending on it's size you may need one or two chain pulleys and/or come-alongs. I bought one of each (from Harbor Freight) and vastly prefer the pulley to the ratcheted come-along. You will need a way to lift your engine with the pulley, it should have lifting eyes, if you use one chain pulley / come-along you probably need to fabricate a spreader to fit between the lifting eyes so you don't bend them - a notched 2 x 4 works perfect. For my boat I used 2 pairs of 2x6's across from the portlights to hook the chain fall and come-along on, and straps from Harbor Freight (USA) to lift my (500+ lb) engine.

You only have to lift the engine a little bit to take its weight off the mounts so you can raise/lower the nuts and move the mounts port or stbd.

If what I wrote sounds complicated, it is not, you DO have to have a way to lift your engine's weight off its mounts, only a little bit, so likely no need to disconnect anything attached to your engine.

But aligning your engine is a huge PIA, it takes time and patience, and after you have used the engine for a few hours you will have to check the alignment again. And every year or two thereafter because your engine mounts will settle and compress.

Of course very few people do this, but once you do it for yourself the first time you will never trust some "professional mechanic" to do it for you correctly. Quote from Nigel Calder, "Accurate alignment is critical to smooth vibration-free running and a long life for the transmission bearings, transmission oil seals, and the stern (Cutlass) bearing." What he doesn't say is that incorrect alignment also causes conventional stuffing glands / boxes to leak too much.

[MicHughV]

true....to venture a quess....maybe 1% of sailors check their shaft alignment in any way, shape or form and off that 1%, maybe 1% actually do something about it.

[skipperpete]

Atlasway, welcome to the forum. tell us more about the installation that you want to align, how powerful is the engine? Type of connection to the shaft? The goal remains the same regardless of the power but achieving that goal varies substantially according to the type of installation.