Shaft Alignment

[bud37]

See heres how I see it...... some boat hulls shift over time, the struts may have shims from the factory or not because of build, are they tight. When your guy checks the clearance around the shaft as it goes thru the tube from the outside will or should tell a story.....he will know or should be able to see if things need to go further that just the engine bed adjustments.......hopefully for you that would be the case. It will be combination of tells ( struts alignment, bearing, strut to stern tube/engine etc.......IMO....just good to be aware of all the options while looking. The more info the better, I always like to go into things like this armed with info, some may be a bit dramatic but asking questions never hurts IMO.

It could be quite simple though, so wait to see how it goes when the boat comes out....

[Viper]

You should have the the type of mount posted in Km's pic. There is a little room on the mount for adjustment which translates to a fair amount when the length of the engine is considered. There may also be additional room for adjustment built into the mounting the engine mount sits on if that's applicable in your case. There should be enough available adjustment between the fwd and aft mounts to get what you need. These are put in place at factory using a jig. If you' can't get a proper alignment with the space that's available, then there is something else wrong that's preventing that from happening; bent shaft, misaligned or bent strut, inexperience, etc.

[Tireless]

I am now at the boat and the plan is to speak to the mechanic tomorrow. The mounts are almost the same as what was in the picture that km posted, but they have a larger base. The mounts are sitting on large plates that are mounted to the side of the stringer. All of the mounts appear to be in a slightly different position, so clearly they can be adjusted to move the engine horizontally, left or right.

The bolts and washers cover the slots completely, but they are also quite large. I am optimistic about there being enough room for the to be adjusted to line up the couplings. I will be able to see the results of the adjustment after the boat comes out of the water on Monday.

We will see what happens and I will update as the process continues.

Thanks to all that assisted up to this point.

Greg

[Tireless]

It is clear that both engines require a drastic adjustment to the centre line of the boat in order to align the shafts. I need to make up for about 1/2 - 3/4 “ on both engines. I now a a full understanding on how we can get both horizontal/vertical movement on both engines to align the shafts from info from the forum and my obs at the boat. It was hard to understand how the alignment could be off that much at the engine, when you typically are dealing with measurements of thousands of an inch, not half’s of an inch. Also there would be restrictions on how far the engines an be adjusted without modifying the engine mounts or the stringer platform.

On Monday we had to remove the boat from the water as the end of the season is here. This gave me and the mechanic a chance to investigate the struts and the clearance through the shaft tunnel thru the hull. I met with the mechanic on Tuesday. He separated the couplings on the on the shaft/transmission to allow the shaft to sit in what I would call a rest position. The couplings remain drastically misaligned.

He checked the cutlass bearings and advised that the shaft was now sitting aligned, where as before it was not.

He removed the dripless shaft seal to allow examination of the shaft at the shaft tunnel inside and determined that the shaft was now resting against the side wall of the tunnel. We then went out and examined the clearance of the shaft coming out of the shaft tunnel. It was not centred as shown in the attached photograph.

He concluded that the struts require alignment on both shafts. Once that is done then the adjustments on the shaft at the motor will not be as drastic. He said that the shafts will not be able to be aligned with the struts in their current position because the shaft will be rubbing on the side of the shaft tunnel. How this is done is way above my pay grade so I will need to take the lead from the mechanic. How he plans to align the struts buy removing them from the bottom of the hull, scrape and clean the joint and then by using fender washers, wedge the base of the struts till they are straight in the shaft tunnel. He will then reseal the strut to the hull with 5200 after they are bolted back in place.

This sounds fair to me but I am not sure if this is the best method. Each shaft has two struts and we need to access the backing plates.

There is an access panel in a stateroom closet to access the starboard aft Strut, but I believe I have to remove carpet on the port side to access the what believe is an access panel to get to the port strut backing plate. The forward struts are going to be a little more problematic. Once I measure to locate where they are, I may have to cut a hole, through the carpet and the floor. Probably use a 4” hole saw. There does not appear to be access panel to access these.

Is this common, to have to cut a hole in the floor, below carpet, to access the forward struts, or should there be an access panel there that I just can’t find.

Is this how you align struts and do you agree with the conclusions in order to finally align the shafts to the engines?

Has anyone that owns a Carver 396, 444 or 44, had to align the struts and understand how you access the struts backing plates?

I welcome any thoughts from the forum so I have an absolute understanding of the best approach to this task.

There are two pictures attached. One is for the starboard engine where the couplings have been separated and the other is the port engine where the couplings are intact.

Thank you in advance.

Greg

[bud37]

Greg, which pic is which ?

There are four struts, examine the bearings in each and determine which struts are installed off. It may just be one a side and then again it may require all to be reset. There will be wear if the rotation has been pushed to one side or another, even up or down. There has to be be wear...also those shafts would have to be at rest as you put it perfectly or so centered in the bearings to get an idea.....IMO

What is your guy using to assist him in aligning this assembly ?

[Tireless]

Bud37, agreed, the bottom picture is the Starboard side with the shaft at rest. The top picture is the port side where the couplers are still attached.

The shafts are centred in the bearings with the shaft at rest. The one that is still attached at the couplings, port side, shows a misalignment in at the cutlass bearing. The way the shafts are now is putting stress on the cutlass bearings and the transmissions.

Greg

[Viper]

Greg, that makes more sense now. I don't know if you had any vibration throughout your rpm range but I would not use a bent shaft to align a strut. I say that because you don't know if the shaft is straight unless they dialed it and did that thoroughly. Even then, were it me and I was going through all this trouble of removing struts to re-bed, I'd go the extra step and remove the shafts and send them into the machine shop to be checked. Just to check shouldn't cost you anything, and if they find an issue, then that's your opportunity to eliminate that as a contributing factor to the problem. Clean them up before sending them off or they will charge you for cleaning prior to testing.

Don't rely strictly on the shaft log to center the shaft as it can drop with the shaft's weight. The shaft should be centered in the tube and wedged in place for the strut alignment. This is best done with the shaft log removed so it can later be reset on the tube and shaft in the new true position.

BTW, it wouldn't surprise me if either shaft, especially the last pic was rubbing up against the tube when the engine first torques up. Look for wear on the shaft at those areas. If there are signs of rubbing, ask the machine shop to assess the shaft's integrity and go from there.

FWIW, it's rare for forward struts to be way off unless there was a major impact. Their short necks make them pretty sturdy and resistant to bending in most impacts. Boat builders usually provide interior access to all struts albeit not the easiest to get to at times, but I can't be sure with your model. Access isn't always directly above and are sometimes offset.

Keep us posted.

[km1125]

Similar (or echoing) Viper's concern... When doing these measurements, did you rotate the shafts to make sure the measurements were consistent and not indicating any bending of either shaft?

[Tireless]

I had the shafts checked when I had the impact 3 years ago and the advised that the shafts were okay. I have asked the mechanic to check if the shafts are true before doing the alignment.

As far as the short struts, mechanic said he would like to remove the two bolts during the main strut alignment to make sure there is no stress there.

I had a minor vibration after the spare props were put on at about 1200-1300 rpm that I could drive through.

Mechanic believes this could have happened at the factory during construction. Cant’t be sure. Surveyor advised that it would take a major impact to bend a strut and there is no evidence of an impact on the strut itself.

What are your thoughts on the method of shimming the struts to correct the offset?

Greg

[Viper]

Washers are fine for shimming as long as you don't need to add something like 1/2" to get it right. Going that high with just washers might be unstable. At that point it would be better to add a thin plate or wedge of the same footprint as the base, then shim with fewer washers.

BTW, there doesn't need to be evidence of a major impact on the strut itself. Most of the curled struts I've dealt with never actually got hit but were curled over by an impact to the prop.

I doubt it left the factory this way, I'm more inclined to believe there was a impact before that just wasn't addressed properly. Don't get me wrong, I've seen some pretty surprising stuff coming from the factories of several brands but never with systems put in place with jigs, lasers, etc. If something happened at factory during assembly, it would still have had to get past visual quality control (an easy one by checking if the shaft is centered in the tube), would have to be missed in an inspection and PDI by the original dealership, not detected in a sea trial and shakedown run, and never noticed or mentioned by all the previous owners, technicians, etc. I think the most likely is a previous impact.