Strut alignment

[paulj]

Witzend

I'm not sure how easy it would be to re-bore the existing shaft log to an oversize and install a new shaft log.....

Could modify the strut while not removing from boat by using local machine shop or fabricater to help give you some ideas and costs.

Well maybe the solution for this problem is based upon local services availiable to you in your area.... or...... for you to learn how do glass work in cold weather...ask charlie cobra.

Hang in there......I do see light at the end of the tunnel.
Arther Godfrey


paulj :troll:

 

[Witzend]

Paul, I considered that idea. The existing tube seems to protrude further inside than necessary to provide a good seal using 2 hose clamps on the log. I'm looking at maybe shortening it and beveling the top inside edge. This would provide greater adjustment to move the engine up some. This probably won't correct all of it, but maybe close enough and minimize wear on the bearing. If this does not work, I believe I will talk to Thordon about getting a blank bearing and having it milled to provide the proper offset.

 

[Witzend]

Brahmany from the 310 fourm

The damper plate does not feel the forces due the a miss-aligned drive shaft, only the output bearing on the transmission. I believe the damper plate failed because it was too stiff for the movement required to smooth out the periodic rotational accelerations and decelerations (torsional vibration) caused by idling a low cylinder count lite flywheeled engine. Basically the flywheel does not have enough mass to absorb these vibrations.
My transmission's output bearing and seal appears to be still OK. Over time these vibrations started to wear the contact points between the collar on the damper plate and the transmission spline eventually striping the collar out. Please refer to:
http://forums.catalina.sailboatowners.com/showthread.php?t=113844
for more information

Sounds like your strut is cocked backwards and moving the engine up to center the shaft in the tube wore your bearing in the opposite manner. Please review the information provided by Roger Long for an alternative to shimming a glassed-in strut (not sure if the C320 is as buried as the C310s strut). Basically you custom mill a bearing blank to provide the necessary offset.

 

[Witzend]

A friend of mine sugested to cut the strut just above the bearing and have it welded back while being held at the proper angle. Comments please?

 

[Roger Long]

A friend of mine sugested to cut the strut just above the bearing and have it welded back while being held at the proper angle. Comments please?

Don't even think about it.

 

[Maine Sail]

A friend of mine sugested to cut the strut just above the bearing and have it welded back while being held at the proper angle. Comments please?

And you call him a friend..? I agree with Roger. I'd dig it out and align it. It's tedious but not difficult. I saw the guys at one of the yards up here using a laser that fit into the strut to shoot straight through the shaft log. You could likely do the same with a rifle bore sight and have a machine shop make you the bore sight holder to fit precisely into the strut just as the bore site sits in the gun.

 

[kloudie1]

That is a great idea, MainSail! It would be pretty simple to make a slightly oversized bushing that would go in the Cutless and have a hole in the center of some caliber .. Boresight would shoot to center mark of the output shaft. A piece of aluminum rod about 5 or 6 inches long, about .008" or .010" oversized (new Cutless) from shaft, then bored for a laser emitting cartridge type boresight.. Still a pretty tedious job because of the shimming and trial and error required, but it would be pretty accurate.. Would be good for someone re-powering too..

Roger is EXACTLY correct .. don't try it because the brazing will pull the bearing shell off center as it solidifies. Very tough (almost impossible) to do that.

 

[Witzend]

Jees... how accurate does this need to be? It has been running for over 500 hours way the hell out, and yes it wore the bearing, but still did not have any play in it. The output bearing in the transmission has no play in it as well and is not leaking. So I don't understand how on the one hand you need a laser to line it up and then on the other hand it has been running with significant alignment problems for 9 years without any significant damage? Remember the engine has movement for alignment correction, so I would think it just needs to be in the range of the scope of the engine mounts while keeping it generally within the center of the shaft tube.

The real question in my mind is will the braze fail? It would seem that there is not much side force being applied here and if the cut is made at the bearing flange, the leverage being applied to the joint would be much less compared to cutting it further up the strut. The brazing could flare out on the bearing housing as well. When the cut is made it can be ground so when the parts contact it will be in forward/aft alignment, and holes drilled for 2 brass alignment pins so it would have no sideways movement when brazed. I need more inforfation about brazing before I will rule this option out.

Digging it out dosen't really scare me, glassing it in again does. How does one keep the resin from running down the strut? Is this done in the factory upside down? Seem like a very messy problem and difficult to keep void pockets from forming. There is a large volume here to glass back in.

Roger, just saying "Don't think about it" without substantiating your comment holds no weight with me. I get the impression you are a very knowledgeable and competent sailor, but please explain? BTW, I have contacted a Thordon distributor and they are looking at providing me a blank bearing. Not sure how I can re-cut the flutes for proper water intrusion needed for lubrication after it has been re-milled, maybe just by hand?

I appreciate all your comments!! This forum is great for gathering others views and experiences and although I may not always follow everyone's advice I do value it.
I generally think outside the box and want to consider all the possible options as carefully as I can.

 

[BobM]

Have you contacted Catalina yet? What did they say? I have heard some pretty impressive stories of how they back their products and if this is a known issue (I'd drop the name of Roger's friend who had the same issue) you may be surprised at how helpful they are. Given your situation you might as well give them a chance. Perhaps they can at least recommend a local shop that has done this job under warranty before.

If you are going to dig it out yourself, I'd use one of the vibrating saw tools, such as the Fein Multimaster, or a clone. That will allow you to cut the fiberglass with a high degree of precision. After using one myself I wouldn't hesitate to use one for this job. Just plan on multiple cuts to outline the whole base using a chiseling type approach. Once you find the depth put a piece of tape or a magic marker mark on the blade so you can control the depth more accurately.

 

[Witzend]

Yes I have a Dremel oscillating tool that is just the checker for this kind of job. Again, I'm not so concerned with digging it out anymore as re-glassing it in. I once built a hot tub out of fiberglass and epoxy resin, so I have some experience in handling this kind of material on a vertical surface, trying to keep it from saging was difficult. Trying to apply it upside down is what concerns me.
I would like to refer you to this post by a very frustrated new Catalina owner Brahmany regarding this very issue: I have not contacted them yet. If this is what I am in for, I'm probably wasting my time.
http://forums.catalina.sailboatowners.com/showthread.php?t=114670
Cheers

 

[BobM]

I agree that the poster was not having much luck, but he is in Australia, which complicates things.

Any more thoughts on shortening the log inside the boat to give you more latitude? You have already replaced the mounts and thought to get the engine to sit low on the mounts, no doubt to reduce vibration. You, like me, likely lack the room to install any sort of CV joint, even if you had the thousands of dollars required to do so. The alternative is pretty much major surgery, as it sounds like your situation reflects mine in that the shaft log seems to be mounted in the hull at a bad angle relative to the back of the engine on top of the skeg alignment issue.

Were I you I would think about how I want to use the boat. If you haven't run it a season with the new mounts and don't have any long trips planned I would replace bearing and run it for a season to see where you are. Don't underestimate the amount of hull flex that can occur out of the water. When it is in the water dive on it and see where you really are. You can also loosen the packing nut inside the boat and check where the shaft is centered in the fitting. Be careful that the hose isn't cocked on the shaft log as that can impact things too. Water will come in, but not a ridiculous amount as long as it is a quick check.

 

[Witzend]

Another idea is to make a cut, but not all the way through leaving the front 1" or so in place. Then heat it and bend it back into alignment by putting upward pressure on the back of the bearing with a hydraulic jack. This way I can control the position of the bearing and get it just where I want it and then have the crack brazed over. See the diagram.

 

[Maine Sail]

Jees... how accurate does this need to be?

This is for setting up the strut and aligning it as it makes for a much easier sight line and is significantly easier than doing it withe the weight of the shaft in place. It's not so much for accuracy as ease of installation.

The real question in my mind is will the braze fail?

Underwater bronze is rarely brazed because it is very tough to do right and the rods rarely match the material make up of the bronze stock which could lead to a dissimilar metals failure. Do you know the make up of the bronze? Is it 85-5-5-5, silicon bronze, manganese bronze, aluminum bronze?

Digging it out dosen't really scare me, glassing it in again does. How does one keep the resin from running down the strut? Is this done in the factory upside down? Seem like a very messy problem and difficult to keep void pockets from forming. There is a large volume here to glass back in.

It's simple you make a very thick putty of milled fibers, coloidal silica & chopped strands then vacuum bag it up in there.. You can also do it by making two stuffing blocks to fit around the strut. You pack it in there, then stuffing it home with wax paper or mylar over the blocks and use large zip ties to hold the blocks to the strut as it cures. Don't go to thick in one application or you'll have an exothermic incident. If you made the stuffing jigs out of Starboard you would not need wax paper. I would use laminating resin, non-waxed, until you get to the last external layer..

Again this is not dificult, but is tedious..


Personally I think all the other options are more difficult than just re-setting the strut..

The other option is to put it back together, align it to .003" and deal with the shaft thump and a worn out cutlass in another 500 hours..

 

[Witzend]

Good point about the bronze make up Maine, I don't know, and it may be difficult to find out, but I could try to find out who supplied these to Catalina and contact them. Not sure if I really agree about the significance of the problem, after all the 3 common versions are not all that dissimilar in term of percentage of Manganese, Silica (which would not be reactive anyway) and Aluminum used, but it is a possible concern.

 

[Roger Long]

Roger, just saying "Don't think about it" without substantiating your comment holds no weight with me.

Perhaps you weren't aware that I've designed more marine power trains than I can recall and stood around watching misaligned strut barrels being corrected with welding. (See: http://www.rogerlongboats.com) You basically use the heat distortion of welding to pull them into final proper alignment by trial and error and I can't imagine doing that with the other end of the strut buried in fiberglass. You might find someone with the skill to do it but I wouldn't expect to encounter them in the average boat yard. Then, there are the metallurgy issues Mainesail discusses.

I can't assess how difficult it would be to reset your strut but, if it's like the one on my boat, it would be way easier to have a Thordon bearing made by a local machine shop. My strut has no bolts or flange but is just buried deep in glass. I wouldn't have it done by Thordon but just get the blank from them and have a local shop make it up. All they are doing after they get it to the right diameter is making the shaft hole slightly angled and maybe slightly off center and putting a top mark on it. It's a plastic so the shop can easily make the grooves if Thordon thinks they are needed.

If there are bolts that you can see and it looks like there is a shaft flange under a half inch or so of glass, it may well be easier to remount the strut. You might still want to put a standard Thordon bearing in as you'll probably never have to worry about it again if you get the strut aligned properly.

Thordon shrinks and expands much more with heat than metal. You put the bearing in dry ice for a while, slide it it, and it's in there unless Thordon has changed it's recommendations since the last time I was directly involved with one. They can tell you the proper clearances.

 

[Witzend]

Did not mean to diss you there Roger, just wanted you to explain your reasons for not considering this approach. I'm sure you have seen many ways to skin this cat and I like your approach to solving this problem best, I just need to get the distributor to get back with me, and since it's the hollidays I will have to wait. Meanwhile the mind races on to think up other novel ways to solve the problem.

 

[paulj]

Witzend

"I can't assess how difficult it would be to reset your strut but, if it's like the one on my boat, it would be way easier to have a Thordon bearing made by a local machine shop. My strut has no bolts or flange but is just buried deep in glass. I wouldn't have it done by Thordon but just get the blank from them and have a local shop make it up. All they are doing after they get it to the right diameter is making the shaft hole slightly angled and maybe slightly off center and putting a top mark on it." Roger Long

Take a oversized Thordon blank, bore to the proper ID add the grooves, then chuck it up in a four jaw lathe and turn the off-set OD based upon the dimensions you take with the shaft flange bolted to the transmission-engine and centered in the shaft log ie..... Use an old or used 1" shaft cut to proper length for mockup.............seems like a two man job.


paulj :troll:

 

[tommays]

I will let you know how re-boreing the shaft log goes as its BAD on my current project boat

The motor is OUT so i will put a 1" id bronze bushing in the strut and make a plate to match the motor which is 3.625 high with 1" bushings

I then plan to use a 1" Thomson shaft about 5' long with a single point adjustable bit and bore it out

I will then use the same bar to line up a new log which will be a G10 tube and epoxy it in place

 

[Witzend]

I dug up these older pics.
The first was from the survey when we bought the boat. The surveyor only grabbed the prop and wiggled up and down and side to side, and then checked for anything bent by rotating it. He never inspected to see if the gap around the bearing was even.

The second photo is after I raised the engine to stop the shaft from slapping the tube. It did not change very much, and is the best representation of what I'm dealing with now that I can show.

Whether or not I can get the engine any higher by shortening what I believe to be excessive length of shaft tube inside the boat and maybe beveling the top inside ( if I think I can get away with it without affecting the integrity of the tube), I don't know. Also not sure how much of this alignment issue is as a result of being on the hard. I'm going to raise the adjustments on the rear jack stands a little and see if it changes.
Again I will take current pictures the next time I'm up.

 

[BobM]

It doesn't look all that bad now

Here is how mine looked and what the alignment looked like on the hard. It got significantly better in the water. The shaft seems low at about 7 o'clock aft, which is exactly how it was before I replaced it, excepting for perhaps a slight improvement (off center by say 1/16 instead of 1/8).

During the alignment another boat owner talked me into dropping the back of the engine about an eighth instead of shimming the front. The engine is currently at the top of the mounts in front. That is what I attributed the slight ringing I had initially, which disappeared and has not returned. I will be at the boat on Thursday and see how it looks this year. I will inspect it, but if there are no apparent issues I will likely leave it alone for now. At some point I will need to address the mounts, but I think I will leave that for a future repower.