We were going from Block to Cuttyhunk with a nice following breeze and sea. The Admiral went below for something and the next I hear is "What's all this water down here?" Bilge was full and the access boards were floating - Uh Oh. Pumped it out then determined the water was coming from aft - in spurts rather than a steady flow. Turns out the flex hose in the cockpit drains had been rigged with low points, and during the winters the fresh water had collected, frozen, and split the flex hose in between the wire coils. A couple of wraps of tape fixed the problem temporarily. Permanent fix was to run the drains with solid pipe and no low points.