Boat Forum / Building / September 2007

Is there not a stuffing box?  Normally there is and one tightens it
around the shaft to minimize leaking.  Not so tight to impede the
shaft but tight enough so that you just get a bit of water.  That
water is then removed occasionally with a bilge pump unless you get it
tweaked so that evaporation = leak.

Being no expert on that fitting, I'll make a guess.  There may be
fasteners through the hull from the bottom, or, it is bonded to the hull.

Either way, the fix is the same.  Remove the fitting, clean out all old
"goo" and replace through hull fitting using new polysuphide (sp) sealant.

You cannot EVER fix a leak by putting goo around the outside.  Silicone
is a bad choice for below the hull fittings.  Polysulphide has a life
span of 20 years.  ±  How many of our boats are that old?

You may not nave to remove the shaft if you can slide the fitting aft
enough to get good access to the surfaces and rotate the fitting enough
to clean it properly.

My opinion here is that anyone who uses the term "goo" does not
understand the difference between the proper sealant for each job.

Jim

Mike,
After reading everything and looking at the pictures, I guessing that
the stuffing box was bonded to the hull with something significant and
later patched with silicone sealer (bad idea).

This is going to be more work, but you will have a better chance.

Go to a real marine store or web site and buy a tube (10oz?)of 5200.  It
isn't cheap, but it is the right stuff to use here.

Now take enough apart so you can go over every thing involved with a
good stiff and really nasty wire brush on a grinder (4-1/2 would do).
 This is the only way you are going to remove the silicone sealant the
you and others have used.  It all has to be gone - completely.  You may
have to pull the prop shaft out of the engine coupling to do this job
right.    If you do not do it right this time, I can promise you will
have another chance and probably pretty soon. (In other words - do it
right or store the boat on a hoist or trailer where it can't sink.)

Well, I just looked at your pictures again.  You don't stand a
snowball's chance unless you pull the shaft out.

You will want to back off the stuffing box and use a file to clean the
burrs off the end of the shaft before you pull it through the packing in
the stuffing box - even if it is backed off.

Now, Once you are POSITIVE that all the silicone goo and stuff is
completely gone from both parts, practice assembling the whole affair
with out touching the mating surfaces with hands or letting those
surfaces touch other things (you will soon know why).  You won't need to
get the shaft all the way home, but it will need to be in the flange -
no key is required at this time.  You need to have the shaft in place
and through the stuffing box while the 5200 cures.

Have at lease one friend and a roll of paper towels handy.

Then, coat both parts with what looks like too much 5200 and start the
assembly.  Once the shaft is in the flange, push the stern tube (that's
the part the stuffing box is attached to) into its place in the hull.
If 5200 doesn't come out all around it inside and out, pull it back up,
smooth out what is there, push what did come out back in and add more
where needed.

When you are sure that you have a good fill and the stern tube is in
place, you can smooth off the excess 5200 so it is not too ugly both
inside and out.

Now, go ahead, try to get your hands clean - I dare you.....
Then sit down have a beer and read again how long it will take the 5200
to cure.  Give it at least that long.  It may be awhile, but you won't
have to do it again - ever.  Don't move the joint until it is a solid
cure - it is temperature dependent - if it is cold, don't rush it.

Only when the 5200 is completely cured can you put it all back together.
 This would be a good time to tend to the stuffing box if it needs any
attention.  You might have to tap the shaft back into the flange (not
uncommon) and do not forget to safety wire the set screw in the flange.

It is also smart to put either a shaft collar or at least a hose clamp
on the shaft between the flange and the stuffing box.  This is just a
little trick to keep the shaft from escaping (and leaving a hole) if it
should come out of the flange.

3m-5200 is a tenacious adhesive sealant.  Removing something bonded with
it is usually better described as destruction than disassembly (but that
is what you ant here).   There is a release solution that arrived on the
scene a couple of years ago.  Just remember that in case you should have
to take this apart because something got damaged.

Mastercraft is a solid and well made ski boat.  It is well worth the
effort to to the job right.

Matt Colie

Below is a diagram from Glen-L. WWW.GLENL.COM They produce and sell boat
kits and supplies such as inboard hardware. This generic diagram shows
arrows representing some sort of mechanical fastener being use to hold the
the shaft log. I would not feel comfortable with the thought of all that
vibration and torque going through that device and there not be a screw or
bolt! Better take a good look at it from all sides!
http://glen-l.com/inboard-hdw/direct-drive.html