Dance of the Seven Sails

The Master's Log:

Work continues on ABISHAG and as with all such work on a boat, more slowly and more expensively than intended. Case in point: thru-hulls. It is never a particularly good thing to have holes in your boat. After all, what sinks a boat is water getting in. However, the medium through which a boat moves is also a necessary component for systems functioning on the boat. The engine for one, the head for another (times two in this case as ABISHAG has one forward and one aft). And not only must water get in, it is a good thing for it to get out less you sink your craft. Indeed for every "IN" there should be an "out", or at least a way for what comes in to get out. Hence, seacocks, or thru-hull, a name that accurately describes their structure. ABISHAG is blessed, or cursed, with 10 through which water passes and three (one speedo and two transducers) through which water doesn't pass, or at least shouldn't, and each has a seacock attached to control the flow of water. On ABISHAG, they are bronze and original with the boat. And that brings us to "galvanic corrosion."

Galvanic corrosion is an insidious chemical/electrical reaction which goes to show that seawater and metals of various kinds don't mix well. Suffice it to say that the process can be impressive and quick, and needs to be controlled and monitored very carefully. Drop a couple of pennies into the bilge of your aluminum boat, be it a row boat or a mega yacht, add a little seawater and you have giant battery, and holes will start appearing in your hull. The use of "sacrificial" zinc anodes usually controls the process as the zincs, being made of a "less noble metal," get eaten up first (sacrifice) before let's say your prop, or your thru-hulls. The most common process of "protection" is to connect, or bond, all the metal on your boat, especially those parts that make contact with the water, to a sacrificial anode system, monitor the anodes and replace as necessary. If you have found the "green insulation covered wire" running throughout your boat, that is your bonding wire. It was put there on purpose and all the metals parts should be connected to in some way, so don't get rid of it! True, there is currently a school of thought that suggests isolating as opposed to bonding, but the proponents are in the minority.

Now I am not sure if one or all of the previous owners of ABISHAG were subscribers to the "isolation" position, but crawling around in the bilge uncovered no bonding wire. There is a 3"wide copper ribbon that runs through the boat. Perhaps our English brethren used that instead of the "green wire", or so I thought. As it turns out, the ribbon is for the SSB Radio and is not part of the bonding system on the boat....of which there really is none beyond the zincs for the shaft and prop and the zincs for the engine.

With this in mind, an examination of the bronze thru-hulls led to a painful discovery. The exterior flanges of most were pink. Bronze, as you know, has a wonderful caramel color to it. Left to weather, it develops a wonderful green patina, like the Statue of Liberty. When there is galvanic corrosion going on, with no protection, a process called "de-zincification" begins to take place. The zinc in the bronze begins to get "eaten up" and it turns the bronze, not green, but pink and it changes from a hard, strong metal to something akin to a stale Saltine Cracker. Wire-brushing the exterior flanges clean of the bottom paint( not a good thing to paint your thru-hulls) showed the pink and a good solid whack with a hammer produced, not the good solid ring of bronze, a dull thud of a metal Saltine and broke the flange as easily as if were really were one.
Not all of them were bad, just the biggest ones and so they will have to be pulled and replaced. This is a interesting process as it seems that the English builders set them in during the last of the lay up schedule which basically means they are fiberglassed into the hull. Ah the joy of sailboat ownership. I guess the person who defined a boat a hole in the water, surrounded by fiberglass, into which you throw money was right.

O, the Dance of the Seven Sails.....coming down the ladder last week, I did what anyone who has ever come down a ladder has done. I missed the last rung and lost my balance. It was at this moment that I went into the dance everyone who has missed that last rung has done. For those of us who have done it in a boatyard, it is known as the Dance of the Seven Sails. Having lost my balance, I foolishly tried to regain it so as not to fall to the ground and look foolish to my fellow boat owners. The moves, the gyrations, the physical contortions must have looked spectacular, even more than they felt. In the end, it was a waste of energy as I landed flat on my back. One of the individuals nearby applauded and cries of "Encore" echoed through the boat yard. Yet I know that everyone of them has done the same and, if not, will one day. The downside was I ripped a muscle in the back of my thigh and butt, and it makes walking, standing, sitting, laying down painful. Unfortunately, there really isn't really a lot you can do except stay off it, eat aspirin, apply heat and try not to aggravate it. Unfortunately, there doesn't seem to by many things you can do that don't aggravate it. So I have had to rest it and have fallen father behind in boat work. Needless to say, my original departure date of International Talk Like A Pirate Day (September 19th) will not be met. Next up, Columbus Day!