Changing prop shaft gland packing

[mike]

Doug,

Your idea of flipping the hose 180 deg worked, the alignment problem went away. i would recomend loosening the log hose, replacing the packing and then aliging the gland, lastly tightening the clamps. I was able to spin the log hose very easly with a 12" long bar between the gland and the adj. studs.
Unfortunately I have to go with the drip-less glands. My seal area on the shafts are too scorred to seal with a GFO packing. It's a difficult job, but may be worth the pain and cost. Week three and still out of the water. Bottom painted and new zinks, Naiads rebuilt , raw water sea-cocks replaced, now working on the drip-less shaft seals and shaft bearings.

[Genesis]

Biggest PITA with that is splitting the coupler halves (easy) and getting the coupler half off the shaft (a REAL biatch)

While you're at it check the alignment and take care of it if you're out a bit.... since you've got the coupler apart.....

[Nonchalant1]

Mike,

Thanks much for the info. I may get up the gumption to loosen my shaft log clamps and spin the hose and gland while in the water. If I do, I'll come back here and post how it goes.

This has been a long thread, so I think I'll respond to Karl's idea by starting another post on shaft-engine alignment. I've never done it. I wonder about that "wobble" even though my shafts don't seem to wobble with a visual check of a pointed stick taped to a strut and pointed 1/4 inich away from the turning shaft to gauge it.

Thanks again,

Doug

[mike]

Genesis,

Your right it's a MAJOR PITA.... the yard doesn't even want to do it. Any recomendations on removing the coupler? I am going to try using a Porto-power, placing the ram between the shaft and a 3/4" thick plate bolted to the coupler with 6" long bolts. The ram i am going to try is a 4 ton cap unit that is about 3" long and has a 1" max extension. The idea is to move the shaft an inch, then put in a spacer and move it another inch and so on until the shaft clears the coupler.

My other approach was to put a thick spacer between the shaft flange and the trans flange and place a large dia scocket between the shaft end and then pull the two flanges together with long bolts throught the origional coupler holes. My concern with this method is that I may damage or bend the trans coupler flange. However I perfer this method it's simpler and lot cheaper, but if I damage the flange it could be far more costly.

What is your expercience with doing this? Any ideas or suggestions are much appreciated. Mike

[GaryNW]

My (30) year old copy of marine SAE stds shows (2) approaches to shaft couplings- taper bore or straight bore. Which did Hatteras use? Also, there are (3) retention methods- a nut (features big recess in coupling), set screw(s) and taper pin. I could see where taper-bore would give the same problem as prop removal. I'm thinking that in addition to one of the methods mentioned for applying tons of pressure, sharp blows with a big hammer might be needed. The coupling is robust and a few dents won't hurt anything- just don't wail on the flange. I guess there is no real way of heating up all that steel? ref: SAE J756

Comment on alignment: If going through the aforementioned bitch, this is the logical time to replace cutless bearings. Engines are aligned to shafts; shafts are not aligned to engines. New cutlesses re-establish the correct (centered) shaft alignment. Ever noticed uneven wear on old cutlesses? I suspect misalignment is more at fault than thrust loads.
Gary

[Genesis]

If the cutless bearings have uneven wear then you are out of line - that is correct.

There is no point trying to align a system that is sloppy. If the cutless bearings are not in good condition, you have to replace them before you can set the alignment.

[Nonchalant1]

So today I fixed the prop shaft gland misalignment by spinning the entire hose & gland assembly 180 degrees (the same as Mike did). The gland hose had drooped from holding the weight of the gland over the years such that the gland was very close to the shaft at the top and very loose at the bottom. So spinning the whole thing 180 degrees uses the hose droop to your advantage to hold the galnd in very good alignment. I did it in the water and very little water came in. All I did was to put a hose clamp on the prop shaft 1/4 inch from the gland to keep it from slipping back, and then loosened the hose clamps on the aft (log) end and spun it around and retightened the clamps. Works great! I haven't run it yet to ensure it's good. Some day soon.

Doug Shuman
1978 53MY

[mike]

Warning!!! Check shaft alignment!!!! I am now deep into it on my main shaft packing gland replacement. As a result of changing to the PYI dripless units I found my stbd trans flange to be loose. On further inspection I noticed that the oil slinger behind the flange between the flange and bearing had been crushed (and lost their pre-load of 280ft/lbs) and that the Trans coupling and shaft have the splines erroded away as a result of poor shaft allignment. This problem did not happen over night, it appears to be years of wear. This has been the haul-out from hell....fixing years of negelect by the previous owner. Caveat-emptor NONE of this was picked up by the survey, ...what a surprise!!!! This also explains why so much packing (5 rings) was in the old gland. The good news is I'll fix it by changing out all the cutless bearings on the shafts, replace the drive coupling and driven shaft in the trans, and add new vibration dampening motor mounts and a flex coupling between the flanges. The end result will be a dry bilge, less vibration and an aligned running gear system, and maybe even less noise .....and of course a much lighter wallet. Mike

[Nonchalant1]

Mike,

If you mean SHAFT alignment, I think I'm OK. If you mean ENGINE alignment, how to check it without a major deal just to check??

Re: shafts - I had all cutlass bearings replaced and the shafts aligned from the winter haulout 18 months ago but never had the "engine alignment" checked. The boat runs, accelerates, and planes with no vibration. The guy that put in my stabilizers said he was amazed at how smooth it was getting up on plane, and he's done a lot of 53MY's and similar boats.

Re: engine alignment - I read David Pascoe's treatise on alignment and he indicated almost no value to using a feeler gauge on the gear flanges. I did what he suggested and checked for shaft wobble at 1200 RPM underway, and found it to be running true. Is there a way to check what you're suggesting without a major operation, just to check??

Re scored shafts - mine seem to be OK, but I wondered if you can just put a longer or shorter hose on the gland to move it to a smooth area of the shaft.

Thanks,

Doug

[SKYCHENEY]

Mike,

How many hours are on your boat? I just thought the rest of us with similar hours should take a close look at our alignments.