[bruce343434]

As the ice expands, I think the ship gets lifted upwards slightly. Water freezing and expanding in pipes and enclosed spaces is the real problem. There's several ways to cool a ship engine, I suspect these all use a system where the "radiator" is a hull feature where anti-freeze engine coolant goes through exposed veins in a closed loop to exchange heat with the cold water under.

[rkagerer]

How about bilge pump discharges? Are those ok because they're open on one end? What about cavities in the pump? (eg. bellows)