Washington, D.C. ? The Navy announced Friday it relieved the commander of a submarine that was involved in an incident that killed two sailors.

On Dec. 29, rough seas swept four American sailors from the deck of the submarine off the coast of southwestern England. The USS-Minneapolis-St. Paul was leaving Plymouth harbor when the sailors were knocked into the water by surging waves. The four men were taken to a hospital in Plymouth, where two were pronounced dead.

According to officials, an initial review determined the incident was avoidable and due in part to a poor decision by the commander. A formal investigation is still under way. He was identified by a Navy statement as Cmdr. Edwin Ruff.