Redid underwater zinc installation

The old installation used two bolts through the hull; the head of the bolt was on the inside of the hull, lock washer and nut on the outside. The electrical terminal was under the head of the bolt inside the hull. This meant that the electrical terminals could not be removed, cleaned, or replaced without pulling the boat out of the water (which explains why the old terminal was rendered worthless by corrosion). Moreover, the bolts used were stainless, which is not very conductive. We purchased extra long silicon bronze bolts, cut off the heads of the bolts, and used doubled nuts with lock washers both on the inside and outside of the hull. This way the terminal can be accessed and replaced without affecting the zinc installation.