Engine Alignment

[Sadey]

I got a call from the yard today asking me about aligning my starboard engine. I’m having the cutlass bearings replaced which appear to be very old. After they struggled to get the bearings out the starboard shaft was way out of alignment. They called for approval to which I did to align the motor. In the process they were able to align the shaft up and down but there are no slots in the mounts to allow for lateral alignment. The mounts and risers are original so it has not been in alignment since day one. I have two choices. One, allow them to grind slots in the mounts for lateral alignment or two, live with it in its current state. The current state is far better than the state it has been in to this point. We have had the starboard transmission off and the motor lifted for that reason to replace the main seal which could account for the more recent misalignment. However based on the mounts it would appear the boat’s starboard motor was never in lateral alignment. They did check trueness of the shaft and they are spot on. There is no issue with the port motor. I do have a slight vibration but there was some damage to the props which could account for that which is being corrected by Airmarine of Chicago right now.
Should I live with something that hasn’t been broken for 31 years or spend the money to allow for a perfect alignment 31 years later?

[Pascal]

At the risk of stating the obvious, do NOT align anything unless the boat is in the water!

[Sadey]

Can you explain why?

[Bob Bradley]

Overall shape/geometry of the boat is different when its sitting on a few piles of blocking than when it is supposed uniformly by the water.

[jim rosenthal]

I've heard that you can do a rough alignment on land. I don't think I believe it, though. I think Bob is right and that the hull and everything else change shape when the boat is in her natural element. I've always launched the boat and given her a couple of days to settle in, and THEN done the alignment.

In this instance, I would spend the money to go for the best alignment you can get.

[Sadey]

That makes sense to me.

[jim rosenthal]

A few years ago, I noticed that when my Hatteras is out of the water for a while, like a week, for her winter haulout, the door to the V berth stateroom closes differently. It still opens and closes fine, it just acts differently. The boat is blocked levelly, and the door doesn't swing differently, but it feels different when it closes. I finally figured out, since I'm not the sharpest tool in the shed, that the door frame changes shape a bit and the door still fits the frame, but not quite as well. When she's launched in the spring, it goes back to normal.

We don't think of a boat, which is a fairly large object, as something that could change shape under pressure, but the fact is that they do. Even FRP boats like we have do. And if you want to see something dramatic, drive around old boatyards and see what happens to old wooden boats that are left on the hard for a few years. They hogback something wicked.

[rustybucket]

second/third/fourth what others have stated. I'd just button it up as-is, idle to the dock at splash, then let the boat sit for a day or two (longer if it's been on the hard for an extended period of time) then do a proper engine alignment.

On my 52c there was a slight change in alignment from on the hard to the slip that had to be made after we splashed.

[SKYCHENEY]

Not sure of your setup, but I have a motor mount on either side of the transmission and one in the center in front of the engine. You may be able to move the front from side to side a little. Not sure and YMMV.

[34Hatt]

All mounts I have seen have slots for side movement.
Every time I have done alignment on the hard and have checked in the water it has been exactly the same on my 34 Hatt.