Thursday, 31 May 2012

The Naked Truth

Exibit A
When we inspected the boat during our first visit, I noticed a patch of rust on the hull around the propeller shaft tube (see exhibit A).  “That’ll clean right up with a good wire brush and a new layer of gelcoat - nothing to worry about,” I was told. 

Exhibit B
We were convinced that the rust was actually coming from the junction of the tube and the prop shaft seal (see exhibit B), which is not particularly worrisome, and can, indeed, be fixed with a wire brush and a little extra polyesther putty.

Now that Spray is “naked like a worm”, as Patrick says, following the sand/water blast of the hull, we see that our trusty rust patch was actually the only thing plugging a crack between the shaft tube and the hull (see exhibit C).  How long it has been there and how much damage the infiltration has caused is unknown and largely unknowable without exploratory surgery.

Exhibit C
The mechanic offered an Armageddon scenario involving a completely rusted shaft tube and massive flooding, with a 30% chance of making it back to port before the boat sinks even with the bilge pumps operating at full capacity.  (Okay, those were not his exact words, but that's what I heard.)  Thankfully, for a mere 2000 Euros, it appears we can avoid all this.  We called in the big guns (Guru Bob and another motor-head friend) to get additional opinions.

In short, they both agree that this is not something to ignore or something that can be treated with a slap of putty in the offending areas.  Guru Bob drew us a graph of the problem, where the red circles indicate our leaks:

Propellor Shaft Tubes 101 by Guru Bob.
We were lucky to be located next to an expert working on a neighbouring boat who overhead the conversation and came over with his hygrometer to check the humidity of the hull.  Everything was fine, even around the affected area.  This is not to say there is no infiltration but simply that the hull material itself has not absorbed any water.

As fate would have it, this discovery comes only 72 hours *BEFORE* we are supposed to sign the final bill of sale.  To be honest, if we can split the costs of replacing the shaft, seal, tube, and stratification, it may be to our advantage to go ahead and have the work done, even if the doomsday scenario is unlikely. The disadvantages?  1) stress in a negotiation process that has heretofore been exemplary, 2) 1000 Euros out of our pockets for the work, and 3) 2 more months in dry-dock !?  There are 2 “stratification guys” that work at our boat yard, and they have an accumulated 1000 hours of work in front of them before they can get to us.  This being France and this being summer, only one of them will be working at any given time in July or August.

Another new concern:  when I mentioned that the current owner had stratified the rudder a year ago, the expert raised his eyebrows in surprise and informed us that this tends to add a lot of weight to the rudder.  Having rapidly perused the Dehler Owner Association forum, it seems that the Dehlers have a rather sensitive rudder system, so now I’m a bit concerned about this potential problem as well.  The owner says it only added 3 kilograms, and anyway, the sandblast just removed it all.  Further investigation required.  For now, I hear a very large Gin and Tonic calling my name.