Re: Cleaning Hull in the water
Back in the 60's a device similar to that described by Brent was widely used, called a "boat bath" it was a plastic liner in your slip. After you pulled the boat in you poured in a gallon of bleach, they worked well and you didn't need to clean the bottom between races.
We also used bleach to catch octopus by pouring bleach over a rock at low tide and gaffing them when they scrambled out. Don't know how much this affected the environment but the octopi sure didn't like it.
Either practice will land you in jail here now.
I used to clean bottoms in my youth, it is truly a PITA, I think most divers are a bargain, you couldn't afford what I would charge.