Since '87
Been keeping my Hunter 25.5 in a bubbled slip during the winter since 1987. The marina has consistently been excellent at maintaining the system and turning it on when the temperature drops enough to form ice. The boat is on a fairly large lake in central Indiana where the lake ices over nearly completely each year. I have never had a problem and the slip has always been ice free. I would paint a different picture if the marina was not always on top of the equipment. One problem experienced at the marina, but not my part of it, occurred when a strong wind pushed an ice flow into the marina one year. The ice was well over a foot in thickness in some areas. This event pushed large slabs of ice into a number of docks, stacked ice a number of layers thick in some areas, and did considerable damage to some marina facilities. A few boats (in that portion of the marina) were damaged by the ice flow as well, but the marina was able to move many out of harms way before damage could be done to them. However, if the winds had continued, it is fair to say that there would have eventually been no safe location within the marina. It did not. I continue to keep my boat in bubbled slips in the winter and feel fairly secure. This allows me to sail both later and earlier in the season.