SS Sankt Erik is an icebreaker and museum ship attached to the Vasa Museum in Stockholm, Sweden. She was launched in 1915 as Isbrytaren II ("Ice breaker II") and was a conventionally-built Baltic icebreaker with a strengthened bow shaped to be lifted up onto the ice to crush it and a forward-facing screw to push water and crushed ice along the side of the hull. She also has heeling tanks which can be filled and emptied with seawater in turn to rock the ship to widen the channel. Her reciprocating steam engines are the most powerful functioning ones in Sweden.