Friday, July 18, 2014

Shafted

When I got home from work yesterday, there were a few unexpected packages on my doorstep.  I had planned on them showing up later in the week or early next week, but the fact that they were there changed my plans for the day.

The parts in question were my GFO Gore packing material for the stuffing box and four Trident stainless steel t-clamps to affix the stuffing box to the shaft log.  These two items were holding up the shaft install; I had gone down to Roses Marine a few weeks back to have my shaft balanced and a new Buck Algonquin split coupling fitted and faced to the shaft.

I was originally going to go with a P.S.S. Shaft Seal to go dripless, but as costs kept mounting I came to terms with the fact that while my old stuffing box was a corroded mess, it didn't take too much work to clean it up and reuse.  So $30 in clamps, $18 for a new stuffing box hose, and $10 for new packing material I was still saving ~$150.

With my new bits in hand, I got started by cutting the packing material based on the article  Repacking Stuffing Box by Maine Sail on PBase/Compass Marine site.  I've used him as a resource for countless problems I've run into over the years and I'm amazed he can spend so much time helping out others.

I used an old shaft I had to wrap the packing material around and cut at a 45 degree angle.  Then I trimmed each of the three pieces a little bit (they end up being a tiny bit long with this method) and neatly packed them into the hollow nut on the stuffing box.  In hindsight, it might have made more sense to wait on the packing material until the shaft is in the boat so you can use it to form the material.  I put it in first and had to push the shaft through the packing and it was a really tight fit.  If I hear any feedback that this was the wrong way to do it, I'll take it out and do it over.

Next, I fitted the fancy new t-clamp hose clamps to the stuffing box hose and the stuffing box and brought the whole assembly over to the boat.  The hose I ordered was specifically designed for packing boxes and is not standard fuel or water hose, it is BEEFY, and almost twice the wall diameter thickness.

Of course access to the shaft log is less than fun, and the only reasonable way to get to it is to lie on top of the engine.  I have nice fuel injector bruises on my chest this morning as a result.  Once in position though, it was just a matter of slipping the assembly onto the shaft log and evenly tightening down the 7/16" nylon locking nuts on the clamps.  These clamps, like the hose are not your run of the mill hose clamp.  First of all they are not perforated as most are and from what I'm told this creates a more even distribution of forces when they are clamped and they don't tend to cut the hose material as well.  Also, the band is 3/4" wide to aid in spreading the load.  Nice clamps...

I should have painted in there, but I'm
going to wait until I pull the engine next year
From there I got off the boat and pushed the shaft through the cutlass bearing and into the shaft log/stuffing box.  As I mentioned before, it was a tight fit, and I took a lot of care to not make a mess of the packing material.  Once it slid home though, it was just a matter of taking the new split coupling and lining it up with the keyway on the shaft, slipping the key in and then tightening down the set screw bolt on the side of the coupling.  Rose's Marine put a nice corresponding spot mark on the shaft so that there was no question as to where it should seat.

Unlike a standard solid coupling, the split coupling allows makes for easier removal when the time comes (or so I'm told).  I've had a number of fun times attempting to remove shafts from solid couplers; it often results in me cutting the shaft to get it out and starting all over.  This should be a better solution.

Before I torqued down the split coupler bolts, I attached it to the transmission so it would spin and I could easily rotate the shaft while evenly torquing both bolts.  All in all it wasn't so bad, certainly better than pulling the nasty corroded mess out in the first place.  Unlike my previous history of stuffing box/transmission coupler neglect, I'm going to try and keep on top of this with regular greasings to cut down on corrosion in the future.




5 comments:

  1. Do you mind me asking what a new shaft cost you? I'm assuming it's 1" SS? My A30 has the original 7/8" bronze, and I suspect I should replace it while everything is apart.

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  2. I didn't replace the shaft, I just had it 'trued'. It is 7/8" Aquamet SS and I replaced it in 2005. I only had two seasons on the new shaft before I pulled the boat, so it wasn't necessary to replace. I believe in 2005 dollars it was roughly $250-300 to have the new shaft machined.

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  3. Thanks. Are you running a two- or three-blade prop?

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