Indigo

[hanleyclifford]

alignment of shaft

Shawn - Don't wait until the boat is in the water to align. It's ok to separate the couplers on the hard, see how far out you are, and go ahead and correct to .003" (or better if you can!) - leave the shaft disconnected until you are back in the water, do a re-check, and then bolt her back together. On a fibreglass boat there might not be any change at all from "hard to water" alignment.

[sastanley]

HC,
Roger, heading out shortly to go work on this.

How do I get to 0.03" ? ? ? I have a feeler gauge set and its thinnest is 0.05. I assume I'll be able to slide a gauge in there without all the rust holding the parts together.

Thanks to everyone for holding my hand thru this!

[hanleyclifford]

Shawn - Once you have separated the couplers, and before you try to check alignment, look at Tom's suggestion about filing the surfaces with a bastard file. After that I like to apply a little machine oil to both surfaces making sure no foreign matter remains on either surface. Your .005" feeler gauge is not going to cut it. Spring for a new set from NAPA with sizes down to .001" and you will get an accurate measurement. Even a well wiped "dirty" feeler gauge can be off .001" or more.

[sastanley]

HC - thanks for the tips..here is the update.

I still don't know what a bastard file is...need to google it.

As suspected, it was WAAAAAY off. (relatively speaking, when we are talking 1000's of an inch tolerance.)

Here is a pic after I got the coupler separated..A little tap with my hand on the sharpened paint scraper took care of the 'bad glue'...what a great idea. I already had one in my tool bag. You can visually see in this pic that it was separated at top & tight at the bottom. When I separated the two pieces, the shaft part immediately dropped...with my fingers around the two, I could tell the shaft was low & the engine was high. So..this pic is bolts out, 'glue' loose, and after I was able to get the coupling back in and jammed together by hand...this is basically the "what I started with state".

I don't have it right yet, but I got it better...I bottomed out the port aft mount dropping the motor, so at some point I will have to start from scratch, as each mount is in some different location between bottomed out and all the way up. It seems also as I rotate the shaft that there is consistent gappage on the port side of the coupling...indicating the engine needs to move to stbd...I loosened the mount bolts & whacked on the mounts a bit, but they will need some 'massaging' to actually move.

By the end of the evening, I got to .005" would fit in the top, but would not slide past 8 or 2 o'clock. I could not get .005" into the bottom of the coupling. As mentioned above, stbd side always got tighter quicker than port. The bottom line is it is better than it was, but needs more work.

This thread has been very enlightening

[hanleyclifford]

alignment of shaft

Shawn - Great job - looks good. Now work on getting all 4 engine mount points free so you can work. From what I can see, it looks like the front of the engine will have to be raised but this is only preliminary. You might want to lose that ss wire on the coupler set screw - it seems to be attacking the coupling.

[sastanley]

hanley,

it has been attacking it since 1977. The only thing the PO ever did with the prop shaft was put some white paint on the coupling to have the prop vertical when he (my father) raced it in the '70s & early '80s (I know this because my pre-race job was to set the prop prior to races when I was a kid!)

What do I replace that wire with?

Also, what is really weird is the port forward mount is all the way up ( I only moved the aft ones today), and the port aft mount is all the way down (bottomed out) - the stbd side mounts are both "somewhere in the middle".

Other than trying to whack the aft mounts to stbd, I attempted to work on one axis and move only the aft mounts an equal amount today.

Maybe a geometry person can help me?

[hanleyclifford]

shaft alignment

Shawn - Actually the wire is a side issue, sorry I sidetracked on it. Regarding the shaft alignment it is important to understand that the shaft is the "boss", it dictates or in other words it must be satisfied first. Take hold of the shaft coupling and ignoring the engine move the shaft around to where you think it is straight in the cutless, or in your case strut bearing - the position you would like to be in if you were the shaft and had to transfer power from the engine to the prop. Some people actually make a temporary jig out of wood scraps and "support" the shaft and coupling in this "most desirable" spot. The engine must now be brought to the shaft coupling. It is rather like the tail wagging the dog, but this is how it has to be. First digest this conceptually, and the actual mechanics of making the alignment will be simple, albeit tedious. A bastard file is available anywhere for a few bucks; I used to know the origin of the nomenclature but I forgot.

[sastanley]

SO, should I spin the shaft (separate from the motor) while the boat is on the hard and cradled by the stuffing box & cutless bearing, and observe from underneath???

What I did today was try to set the shaft half of the coupler such that there was no visual bias on the stuffing box and then push it into the engine half of the coupling to see how things lined up. Recall that I had visual alignment problems at the stuffing box (most notable with the engine in gear), which meant that I likely had 'shaft whip'?? at the extreme prop end, if I have my terms correct.

I am running short on time (40 hours to splash), but I have lots of leave at work. I'd much rather tinker at the boat than sit in the office.

[hanleyclifford]

shaft alignment

Shawn - Your use of the term "shaft whip" is correct. Because of the severity of your misalignment and the longevity and the motor mount problem, most likely a view of the stuffing box will be misleading. The most important consideration is that the shaft run true in the strut bearing. Ignore the stuffing box for now since the shaft log (hose section) is probably distorted. Getting the shaft true in the strut bearing will involve climbing in and out of the boat many times until your temporary "cradle" inside the boat holds the shaft exactly where you want it - no need to spin it. Of course we are now assuming that the shaft is indeed straight. This is the part that must be done on the hard, since once you are in the water you cannot check the strut bearing. At this point the shaft and shaft coupling should be right where you want them. Now begin to move the "dog" toward the "tail" without changing the position of the shaft coupling. No need to do any spinning until the engine is where you want it. In order to move the engine on all four of its feet it is important that all 4 motor mount studs have clean lightly oiled threads so you can make fine adjustments. Also the lags holding the feet to the sleepers will have to be loosened so you can adjust athwartship. Maybe you could post a picture of your motor mount.

[Marian Claire]

Great info. Sounds like you could loosen the lags on all mounts except for the starb/aft and nudge the fly wheel end to port. That may get you to 2 and 10 so “side to side” are even. If the port aft nut is all the way down and the port forward nut is all the way up could you shim under the port forward mount to gain some thread/adjustability? Then adjust both forward nuts up to close the “top to bottom” gap. All this is based on the shaft being right as it sits now. Dan S/V Marian Claire

[ndutton]

Shawn,

After you launch and realign please post back regarding any changes. Depending on how they're supported or blocked in the yard, it's my experience that lighter fiberglass hulls like ours can take on a dramatically different set in the water.

At Capital Yachts there were several times we had to adjust the head door after a Newport 30 was launched. The door fit well in the shop but wouldn't close in the water. Our wood cradles weren't adjustable and I suspect we had a few that supported the hulls a little differently than others.

[sastanley]

Thanks all, will do. I understand the engine/shaft arrangement may be different when floating, & will look at it again after splashdown. The boat is supposed to sit at the marina thru Saturday (mast stepping) so once she's floating, I may have some time to tinker again.

I only plan to spend a few hours at work today, so I'll be back at the boat by lunchtime I hope & can snap some more pics. To really beat on the port mounts (athwartship movement), I'd probably have to remove the waterlift muffler & batteries, cables, intake hose, etc., unless I can come up with some clever way to make a lever arm. At least all of the up/down adjustments are free and moving well. I am guessing like everything else in the boat, the mount feet were never moved, so the mounts are 'welded' to the boat. I can get all the lags loose, but no movement.

Neil, funny you mention doors..on my stepfather's Tartan 3000, the head door wouldn't close for years..back when we were racing it hard, we started drying the boat out with a dehumidifier..after a few weeks, viola! the door suddenly "fit" in the frame again!

[Marian Claire]

I know access on the MC is better than on most boats. Do you have room to use a small hydraulic or scissor jack to move the engine? Nice smooth pressure. Just an idea. Dan S/V Marian Claire

[sastanley]

Dan,
Good idea, but not sure where I'd brace it from the other end...that's kinda the issue..If all those parts were out of the way there is just a rounded empty hull..thanks and keep the ideas flowing!

[tenders]

With all this talk of 0.003" tolerance between the two couplings, it is not clear to me how you can tell where the "natural" or "ideal" position of the shaft coupling is to within anywhere near 0.003". With our without a jig, or suspending the shaft from a string, etc.

Why so much (false) precision?

Could it be that the 0.003" is the maximum tolerance you can have between the two couplings ONCE everything is bolted down?