With the Shearwater out of the water for repairs it seem the most opportune time to take care of some of the scheduled maintenances.  First on our list was the removal of the propellers to change the zincs.  Unfortunately, removal of the propellers required removal of an Allen head machine screw and the propeller cone.  Fortunately, both were treated the last time they were removed (to replace a lost propeller), thus removal should have been easy.

I removed the first Allen head screw - and the entire assembly came off in my hand - I cracked the propeller shaft in the process.  Click on the photo below of the port shaft to see more details.

   SD-20 Port Shaft

With the second prop, I was determined to be more careful with the starboard shaft.  I enlisted the help of my second mate and chief photographer, Elizabeth Anne, inserted the Allen head wrench, tapped it lightly with a leather hammer to seat the wrench and turned it with one finger - snapping the shaft in the process.

  SD-20 Starboard Shaft

As you would expect, both the port and starboard hubs were damaged and showed clear signs of breaking in exactly the same place:

         Port Cone (hub)                         Starboard Cone (hub)

During the search for the cause for two snapped propeller shafts, I found that Yanmar had redesigned the shafts and was no longer selling the style shaft installed on many of our boats.  The new style shaft was an exact replacement except for the omission of a no-longer-used hole where my both my shafts broke.

Since this seemed like a warranty issue, I enlisted the local Yanmar dealer to do the actual replacement.  Jaz Marine in Riviera Beach did the work and helped me with the claim.  It took a month or so, but Yanmar eventually approved the claim and paid me back for most of the work.

If you have the shafts with the old cotter pin hole (you must remove the hub to tell), contact Yanmar - they now have a replacement shaft available.  You must negotiate your own deal for payment - but at least you won't lose a prop and be stranded when the old style shaft snaps.  Unfortunately, Yanmar has declined to tell me what engine serial number and sail drive models had the old style shaft installed at the factory.  They have also not issued a general dealer recall to pull the old style shafts off the shelves if any are left unsold.

Lost your propeller?

Several Voyage Yacht owners have discovered another unfortunate characteristic of the Yanmar SD-20 sail drive used instead of a marine gear, shaft, packing, and cutless bearing used on more conventional boats.  Great idea on paper, the power is delivered to a better place in the water, the installation bed is less complicated, and the engine, transmission, and propeller are all one piece.

Well, most of the time.  One of the few Volvo parts on a Yanmar engine/sail drive combination is the propeller and hub that holds it on.  Unless you are very careful or very lucky, these will fall off eventually - costing you about $250 for a new prop, hub (the big piece above), and the two washers required for the installation.

First note of impending doom - ours failed in the middle of nowhere.  When we ordered the prop and hub kit - we had no idea the thrust washer was not included or we would have ordered that also.  Two weeks later when they came from the states - we had to remove the other prop to find why the failed one wouldn't go on.  A nice machine shop manufactured us a thrust washer - and several people told us to install the hub and allen head machine screw with RED Locktite.  Locktite comes in several colors - apparently the demons who take props are scared off by red.  It has stayed on so far.

Greg on Magic, another Voyage yacht, shared the solution used by Sun Yachts on their charter boats.  Apparently Sun imports these parts from Yanmar England - but I can't find the part number and have been unable to get them on my own.

The photo on the left shows two of the elusive parts.  If you click on it and view the enlarged photo, please note the locking hex machine screw facing you on the top nut.  The dull gray part is an additional zinc (replacements available from Budget Marine).  Unfortunately, I can't source the nut itself - so until I go to England and find a Yanmar deal who will sell me one, I'll keep looking.

Neat solution to a serious, or at least inconvenient, problem.  If you happen to know the Yanmar part number or where I can purchase a set of these for the Shearwater, please e/mail me.