Simple winterizing
Here's an easy way. You need a 5 gallon bucket, a 1/2" thru hull to install in the side of the bucket at the bottom, 7gallons of water system antifreeze, and 3 gallons of engine antifreeze.While the boat is still in the water, run out all your tap water and thoroughly pump out and clean the waste water tank. Then close the seacock for the head, remove the hose from the seacock and attach it to the bucket (thu hull) dump in two gallons of water and pump it through the head into the holding tank. In my case the air conditioner is on this line so I turn it on and let it run until it is pumping pink stuff overboard.Haul the boat, when it is in the cradle, pull the hose off the engine seacock and attach it to the bucket. Dump in three gallons of engine antifreeze, start the engine and run the bucket dry. Take the lines off the hot water tank and pipe them together end to end with duct tape. Let the hot water drain into the bilge and then use it to scrub the bilge out. Dump 5 gallons of antifeeze into the water tank and then run it out of the all the taps making sure all through hulls are open and that the pink stuff has circulated all over the system. You could pump out all the antifreeze at this point and have no worries. Pump out the bilges and dry with sponge. You are done.