[Uhehner]

When I lived up north I would just pour straight non toxic anti-freeze into the sea strainer until I could see it coming out the exhaust pipe with good color. That would take care of the engines, strainers and the mufflers. Come spring I would catch as much as I could with buckets while running the engines on land. Then I would test the freeze level, add more antifreeze and save it until next fall. Remember this antifreeze does not have to stay liquid all winter. It can turn to slush, you are not running the engines. You just don't want a hard freeze. Don't forget the hot and cold water system, heads, shower sump, wash down and A/C pumps and also dump some in the bilge.
Capt. George