If I was in Washington I wouldn't do anything unless there was a hard freeze forecast. Then I might do what I mentioned below. During the 28 years I lived in Washington hard freezes happened maybe 10 times. I have never seen a frozen harbor in Washington. In fact, except for up in the mountains I never saw a frozen body of water until I moved to Fairbanks, AK. For reference, many of the harbors here in Maine don't freeze. I also see quite a few boats that stay in all year here too.