Due to the arduous nature of U-boat duty, uniforms varied greatly depending upon the actions and activity of the service member. All submarine personnel were required to maintain standard Navy uniforms, with the undress service uniform being the most commonly worn when on shore. Upon departure and return to base, especially when the submarine was visible to onlookers, officers would wear a modified version of the service uniform to consist of the blue service coat along with grey all weather over-trousers. Commanders who had earned the Knight's Cross would often wear tin copies for the ceremonial entrance and exit to port. All medals, ribbons, and badges were removed once fully underway at sea.