Part of what was being learned with this test was if copper letters inhibit biological growth in a radius large enough for the text to remain readable when copper letters are fastened to a non-copper surface.
This is a test section of a peace pole. It has a vinyl "X" on top of a copper "X" on top of stainless steel that is mounted on vinyl. It was done haphazardly in order to increase the likelihood of failure in order to find weaknesses. It spent a few months hanging, 5 feet from the bottom, 10 feet from the surface, in the Ohio River in a 5 knot current. We got a glimpse of how organic life is effected by the copper "X." In the Ohio River the stainless steel trim tabs of boats are covered with moss within a month of launching. Eventually zebra mussels take residence on stationary objects, like they did on certain parts of this experiment.
Test section of Peace Pole BEFORE immersing in water
3.5 inches X 3.5 inches X 6 inches
For the final pole, the cement base seen in Stage One might be useful. At its center it could have a larger diameter but truncated shaft into which poles could be inserted for the duration of their stay in the ocean kiln. Unless I am able to make a pole that is buoyant in spite of incorporating metal, which might be possible by attaching a float to it's top. In that case, all that would be needed is a chain and an anchor.
I have a suspicion that the best underwater pole would be made of bronze with letters cut out of copper.