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

Paul:

It all depends on the design and layout of your prop shaft support system.
Designs with a stern tube and a separate prop shaft strut with a cutless
bearing will support the prop shaft very well at two points and since two
points define a straight line, it will stay pretty true even when you unbolt
the coupling.

But if the only support is a stern tube cutless bearing, then the prop shaft
will sag a lot when you unbolt the coupling. In this case the only support
is a 4" or so long cutless bearing and it will sag quite a bit.

It sounds like you may have the latter design and you can wiggle the prop
shaft up and down to get a feel for its real center absent gravity. But a
half inch is probably close enough.

David