In a message dated 11/4/2005 9:01:16 PM Pacific Standard Time, trawlers-and-trawlering-request@lists.samurai.com writes: Paul Brannon wrote: >After all of the conversations regarding dripless shaft seals, cutless >bearings, and engine alignment I disconnected the shaft from my starboard >transmission to correct a problem with a seal leaking. I noticed that when I >disconnected the flange that the shaft could drop a ways (maybe a half inch?). >There was lots of play in the stern tube. Is this normal? If so, how would >one check alignment with all of this play in the shaft? I may be hauling out >for bottom paint and want to make any corrections while it is out. > >Thank you, > >Paul Brannon >1978 Gulfstar 44 MC Hello Paul Your post addresses an often over looked part of shaft alignment on boats with one cutless bearing in the stern and a stuffing box clamped to a rubber hose what your seeing is normal. The bearing is to far from the coupling to support the shaft so it drops from it's own weight until it hits the bottom of the shaft log. Now you can just lift it up and slide it forward so the male pilot in fits into the female on the coupling and do your alignment that's what most people do. The problem with that is you have no way to know if the transmission flange is in line with the shaft log and cutless bearing you can get good readings on your flange alignment even though the engine is out of line with cutlass and shaft log. To correct this you could haul the boat pull the shaft and use a string or a laser to line everything up but that's a lot of work and expense that's probably not justified unless you have some other problem. What I do is assume that the shaft log and cutless bearing are in line and they usually are it's the engine that's typically out of line. The reason for that is because over time the soft rubber engine mounts compress from the weight of the engine and the effect of the rotational forces. knowing this heres the procedure I use to get a good and complete alignment. Separate the coupling from the transmission and let it rest on the bottom of the shaft log create a reference point to measure from below the coupling. Take a measurement from the bottom of the coupling to the reference point make sure the shaft is resting on the bottom of the shaft log if the stuffing box hose is stiff or very short you may have to push it down. Now lift the shaft up until it hits the top of the shaft log and take another measurement from the reference point. Now prop the shaft up exactly in between the two measurements prop it in such a way that the shaft can still move from side to side and slide forward. Now use the same procedure to center the shaft side to side and prop it in that position. The shaft is now centered in the shaft log and held nicely in place now do your alignment if you have some hours on your boat and this has never been done you will be amazed at just how far off it probably is. If it was very far off you might also want to re pack your stuffing box because it was not parallel to the shaft and has probably worn UN evenly. You will probably also find that it will require much less maintenance in the future along with your cutless bearing. You may also loss some vibration a happy driveline is a beautiful thing. Brian Palmetto FL >_______________________________________________