"Milton Waddams" wrote in message
...
Does all the bottom growth that happens dockside occur only during
daylight hours? Can it occur in the absence of light?

Most bottom growth is animal growth. Perhaps about 20% is plant growth.
Therefore, the absense of light will only stop the plant growth and not
the animal growth. But, keep in mind that water reflects light pretty
substantially. Even at the bottom of the average boat there can be
enough light for many plants to thrive.

What is the minimum speed a boat must be moving through the water
to prevent bottom growth?

Bottom growth happens even on the hulls of fast boats. This is because
of something called the "boundary layer". The boundary layer is a layer
of water that moves along at the same speed or close to the same speed
of the hull itself. Plant and animal growth find it not too difficult to
attach themselves to the hull when caught in the boundary layer because
the hull is barely moving with respect to the organism.

I'm doing a gedanken experiment and any help would be appreciated.
If it looks like it will work out I'm really going to try it.

For thought experiments it helps to put yourself in the place of the
organism you are concerned with. Picture yourself as an almost
microscopic form of plant or animal life and picture yourself caught in
the boundary layer. What would you do? You would probably attach
yourself to the nearby surface is that was your wont. A plant wants a
place with adequate light and an animal might even prefer shade or
darkness. The more growth that exists on the bottom of the boat the more
chance an organism has of finding a suitable niche.

Wilbur Hubbard