We are soon to experience our first bottom job. Now there are those among you reading this whose thoughts may have immediately strayed into the realm of the unseemly, but please rest assured, this bottom job is quite mundane.
Boats that sit in the water, particularly the warm water of a Florida marina, collect all manner of hard and soft critters which attach themselves with varying degrees of tenacity, to the bottom of the boat. Left unchallenged, these critters can become a veritable underwater forest of biodiversity.
Imagine sliding your bare hand through the water…that’s what a nice clean boat hull is like when the boat is moving.
Now imagine wrapping a thick woolen sweater around your hand and trying the same sliding-through-the-water thing…that’s what a “fouled” hull is like.
It takes a lot more fuel to move the boat, and it’s just generally not good to be dragging a mini-ecosystem around.
So, the answer is to paint the bottom of the hull with a paint designed to discourage critter-attachment, and then to have that painted surface scrubbed from time to time by a diver. The paints made for boat bottoms contain different types of biocides, and at this time, the predominate biocide seems to be copper. Used to be that tin was the preferred biocide, and it apparently worked quite well. Too well, in fact, because all that tin leaching out of all those painted boat hulls started causing problems with “good” critters. So tin was essentially banned, and copper took its place.
Our boat’s hull is painted, but our diver has informed me that the paint is wearing thin, as it is designed to do, and needs to be reapplied.
Once it’s been blocked up and is stable, I’ll have the old paint removed, and then we’ll start applying the new stuff. This is where things get a little pricey. Bottom paint is sold by the gallon, and based on the cost per, it would seem that the active ingredient is not copper, but pure gold.
It’s pretty much theirs to price as they see fit though, so there’s not much to do except grin and paint it. It’ll be nice to have a slippery bottom again.