It depends a great deal on the salinity of the water...
I am new to the Bay. What are the considerations for living on board during the winter? Do the marinas shut off the fresh water? If you leave the boat for a few days, is freezing an issue? Do you need bubblers?
Are there other possible problems? Thanks in advance for any opinions.
I keep my boat in the water year-round not too far south Annapolis. My marina almost never freezes, though there may be a few days during here would be difficult to get out. There might be a quarter inch of ice on the water, but it will be mushy ice and not damaged boats. However, just a half a mile away from me on the different fork of the creek, it is very common for boats to be locked in for weeks at a time. That fork in the creek is less saline than mine. It is often very telling flying into BWI Airport; some creeks and marinas locked up and white throughout the winter, and some stay clear throughout the winter. It would be best to ask local residents.
A bubbler can never hurt, but I doubt it would be necessary south of Solomons Island. North of Solomons Island it would be good insurance, though I only use mine on rare occasion. I only use mine on rare occasion, perhaps only one year out of five.
Yes, the marinas will turn the water off. Getting your head pumped out will be something of an issue too. Though I do not live aboard, I sail all year and spend some nights aboard - it's a pleasant diversion. You're careful to minimize the use of the head. Because there is some risk of freezing, I keep a jug of very weak antifreeze in the head and use that for flushing. I don't use the fresh water system, I keep drinking water in jugs. I suppose if you kept the heat turned on in the boat, all of these problems go away.
If you have any air gaps around companionway slides and hatches they will need weatherstripping. Keep the snow swept off when the snows - you don't want your heater pipe getting blocked.