What temp is really "freezing" on the water?

[mhinnc]

Q. Is there a general rule of having a little lee-way, temperature wise, in winterizing a boat?

This summer we acquired a C&C 30. It is docked at East Beach/Norfolk.
The boat has a raw water Atomic 4 engine. It's our first boat with an inboard.

The forecast is for the air temp to drop to 31 deg F tonight. Specifically, the current forecast is: "Clear to partly cloudy. Low 31F. Winds WNW at 5 to 10 mph." The forecast is for the air temp to be a high of 47 deg F today.

This is the first sub 32 deg for this season. Original plans were to go up today anyway. (I'm 5 hours inland), but some things popped up that makes it a little difficult to get there today, but not impossible to get there by late this evening.

Does the inside boat temp (sunshine), help hold a little heat through the evening; does the water temp under the boat help provide any relevant warming? Should I drop everything and make a bee line for the boat to winterize it?


Thanks for any advice/insight.