The USMC or USN training Sweater in the 1930s-1940s use one-word collar, which was helpful for sailors to take off their clothes quickly after falling into the water. To facilitate sports, the shoulders were very wide, close to the chest, and some even exceeded the chest width. This is according to the pattern cutting of the first year, the thickness and texture of the fabric are very close to that of the first year, and there is no blindly thickening. The current thickness is a setting made after weighing the advantages and disadvantages. Only when the first year feeling is presented, can "recarving" really have meaning.