Wednesday, January 22, 2014

More on the strut bolts

--Blog post written by Bob

The strut and propeller shaft were removed
 just after haul out.

Our boat was hauled out and kept in the travel lift (with large wood blocks under the keel for stability) while the strut work was being done.   The strut and the propeller shaft was completely removed immediately after haul out.  The strut had been sealed with a dark gray putty-like material--the same material used in the hull-to-deck joint.  The shaft strut was reassembled to the hull and was re-bedded using SIKAFLEX 291 as the sealant.  (SIKAFLEX 291 is a sealant that is somewhere between 3M 4200 and 3M 5200.)  Upon reinstallation, the mounting bolts were upgraded (from stainless steel) to bronze to provide greater corrosion resistance and eliminate the dissimilar metal concerns since the strut is made from bronze. 

New bronze strut bolts were installed,
 replacing the original stainless steel bolts.

Strut and propeller shaft back in position
 but before fairing and touch up paint were applied
The cutlass bearing (located in the shaft strut) was in good condition and replacement was not needed.

As the propeller shaft was reinstalled through the strut, the new PSS shaft seal was installed.   The bearing faces on old the shaft seal showed absolutely no wear--so, the maintenance kit would have worked fine.  While the boat was hauled, new zincs were bolted onto the shaft.  (Zincs are used to protect the stainless steel shaft from galvanic corrosion--the zinc is sacrificial.)

New PSS Shaft Seal in Position

The old PSS shaft seal was kept as a spare in case we need an emergency replacement in the middle of nowhere.  However, if the shaft seal ruptures at some point in the future, we probably won't be able to handle the volume of incoming water with our bilge pumps.  We would have to get to a haul out facility quickly.  Even conventional packing glands usually have a rubber hose (between the stern tube and the packing gland assembly) which could fail.  Fortunately, a failure of the kind is very unlikely but I think I will add another electric bilge pump set to pump at a higher level than the current one.
Ice on the Creek at the Boatyard

The shaft strut work and shaft seal installation took about 2 days.  The boat will be put back into the water for the remaining work on the fuel tank installation, after we get through the current cold weather we are experiencing--it has been between 10 and 20 degrees F at night and hasn't been above freezing during the day this entire week!

Even though a lot of work still remains, all the big problems have been figured out (hopefully).  

The installation of the new fuel tank is next…

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