Can you tell me how to prevent water going in through the drive shaft?
This will be under water line and submersed area.
Is there any special water proof bearing used?
How does that work?
Thank you?

"Anderson, M." wrote in message
...
Can you tell me how to prevent water going in through the drive shaft?
This will be under water line and submersed area.
Is there any special water proof bearing used?
How does that work?
Thank you?



If you are talking about a standard shaft seal, it is supposed to leak very
slightly, meaning a few drops per min. to provide lubrication and cooling to
the seal. The shaft seal packing occasionally needs replacment and the
packing nut occasionally will require an adjustment as the packing wears.
If the packing nut is too tight and there are no drips, you run the risk of
burning up the shaft seal.

There are dripless shaftseals available that will not drip. They require
water cooling lines to operate.

Eisboch

Eisboch wrote:
"Anderson, M." wrote in message
...

Can you tell me how to prevent water going in through the drive shaft?
This will be under water line and submersed area.
Is there any special water proof bearing used?
How does that work?
Thank you?




If you are talking about a standard shaft seal, it is supposed to leak very
slightly, meaning a few drops per min. to provide lubrication and cooling to
the seal. The shaft seal packing occasionally needs replacment and the
packing nut occasionally will require an adjustment as the packing wears.
If the packing nut is too tight and there are no drips, you run the risk of
burning up the shaft seal.

There are dripless shaftseals available that will not drip. They require
water cooling lines to operate.

Eisboch



It's as Eisboch says for smallcraft shafts but........ if by your
headers you meant actual "ship" prop shafts???

They're properly engineered because unlike a pleasure craft prop shafts
they're designed down pretty close to the line in that a shaft carrying
substantial HP AND the prop's thrust/vibration etc over sometimes a
reasonably long distance needs lots of proper lubrication & support
bearings,not bushes but big roller or ball bearings; usually as follows;

(i) The prop shaft runs on bearings in a thick walled hollow tube. The
tube is machined etc to carry the bearings & proper pressure seals both
ends. It all runs in oil, sometimes pump lubricated other times just
kept at a head of oil pressure with a header tank, just so long as any
seal failures will be immediately detectable & oil will leak out (& be
replaced) rather than sea water leaking into the bearings etc.

(ii) The enclosed part of the shaft & it's bearing carrier of (i) above,
as a unit (the length that goes through the hull, forward of that is
often open inside the engine room & aft is only a short distance to the
prop itself.) is usually flange mounted into a second larger diam tube
that is part of the steel ship's hull/keel etc. Because the that tube
which is part of the hull cannot be guaranteed to remain total straight
& true (weld distortion into the ship, then the ship itself changes
shape when loading/unloading etc).

(iii) In the event repairs are needed particularly machining etc, the
whole shebang, shaft bearings carrier etc can be readily removed from
the ship:-) Probably more than a 5 minute job with a shifter & hammer
for sure, but they regularly do it:-)

K

& the Krause lie of the day is a newie but a goody:-) This idiot has
never been able to even begin to enter any coastal nav thread much less
the many celest ones over the years, yet he recently produced this lie,
well it's another classic Krause lie:-)

Have a read of this I mean it!!! He's a nut case a complete nutter:-)


I took my *first* course, in piloting, with my then best friend,
Steve, when
we were about 11-12 years old, by special dispensation of the US Power
Squadron in New Haven, Connecticut. The class was held in the
evenings in the
basement of one of the Sheffield scientific buildings, on Prospect
Street, if
I recall, on the campus of Yale University, across from Woolsey Hall. Our
parents dropped us off and picked us up; the classes were in the
evenings.

We were at that time the two youngest enrollees in such a course in the
history of the USPS. We completed the course successfully. It was
about 45
years ago, when piloting and navigation were done with hand instruments.

How did we get in at such an early age? Both of us had started yacht club
sailboat racing in dinghies at the age of 8, and by the time we were
11, were
working individually and as a team, competing successfully in southern
Connecticut junior racing circuits. It also didn't hurt that my
father was a
boat dealer and marina operator and also a by-then retired boat racer
of some
fame, and that Steve's dad was a well-known sailboater out of the
Branford,
Connecticut, area.

Steve now sails out of the Maritime Provinces.

K. Smith gets it wrong as usual:

They're properly engineered because unlike a pleasure craft prop
shafts they're designed down pretty close to the line in that a shaft
carrying substantial HP AND the prop's thrust/vibration etc over
sometimes a reasonably long distance needs lots of proper lubrication &
support bearings,not bushes but big roller or ball bearings;

The line bearings are plain bearings, bushings if you like or split
shells supported in large bearing blocks, each incorporating an
independent oil sump and sometimes a cooler. Lube oil is supplied to the
bearing by use of a simple ring of larger diameter than the shaft. The
ring hangs on the shaft and friction between the shaft and the oil film
drags the ring through the oil sump, carrying oil to the top of the
shaft where it spreads out by gravity and lubes the bearing surfaces.

Rick

For small craft in board electric motors, how do they design the dripless
shaftseals ? Any reference material online? Thanks

"Eisboch" wrote in message
...

If you are talking about a standard shaft seal, it is supposed to leak
very
slightly, meaning a few drops per min. to provide lubrication and cooling
to
the seal. The shaft seal packing occasionally needs replacment and the
packing nut occasionally will require an adjustment as the packing wears.
If the packing nut is too tight and there are no drips, you run the risk
of
burning up the shaft seal.

There are dripless shaftseals available that will not drip. They require
water cooling lines to operate.

Eisboch

Anderson, M. wrote:

For small craft in board electric motors, how do they design the dripless
shaftseals ? Any reference material online? Thanks


http://www.shaftseal.com/

On Tue, 29 Mar 2005 19:11:25 GMT, Rick
wrote:



Anderson, M. wrote:

For small craft in board electric motors, how do they design the dripless
shaftseals ? Any reference material online? Thanks


http://www.shaftseal.com/

Yep, I designed them myself for that company.