Originally Posted by sailingdog
Pouring antifreeze into the water is probably illegal in most states...YMMV...but I doubt the local water police would approve, and the fines can be both steep and nasty.
Most boaters (especially sailors) are sensitive to the environment and use only Propylene Glycol Antifreeze
in the raw water sections of their boat's engine. Hopefully you do as well.
I always buy undiluted and mix it 50% with water in a five gallon bucket. A hose is then fed to the sea water strainer, which draws the solution into the engine after starting. As previously mentioned, I also shut down as soon as it's seen exiting from my wet exhaust.