Engine to shaft alignment whilst out of the water

[Amp1ng]

Hi all,

Following cutlass replacement, Volvo shaft seal and gearbox reinstallation I was advised to do some basic alignment whilst out on the hard followed by a recheck once in the water. I did this by centering the shaft in the tube using a machined spacer whilst the new seal was out of place, then butting up the flange faces of the rigid coupling as a rough check. To begin with the alignment was quite a bit out (visible to the eye against the outside diameter of the flanges) and involved lifting the engine up and tilting it aft. Whilst I spent the best part of Saturday afternoon climbing in and out of the engine bay adjusting front and rear engine mounts it occurred to me that all this might be a complete waste because whilst standing on the hard the hull will be sagging at either end. Have I just spent a load of time making adjustments that will need to be reversed once back in the water? The boat in question is a Westerly Fulmar twin keel, what should I expect to see in terms of discrepancy between shaft and engine from one state to the other?

 

[Tranona]

Doubt there will be much, if any movement when the boat goes back in. The advice to align in the water dates from the days of wooden boats which often did change shape as they took up in the water.

You can check after launching by backing off the flange bolts and sliding the shaft back a bit to clear the register in the flange. If it is severely out of line you won't be able to push it back together, and you can check the gaps between the faces to be sure. If you have an R&D coupling measure the gaps using the method in the installation instructions. Be careful you don't push the shaft back too far if you have a rope cutter as it can come out of the block.