High Quality Content by WIKIPEDIA articles! A sailor cap is a round, flat visorless hat worn by sailors in many of the world's navies. A tally, an inscribed black silk ribbon, is tied around the base which usually bears the name of a ship or a navy. The cap may be further embellished with a badge, cockade or other accessory. Visorless caps of this kind began to be worn in the mid 19th century. The more rigid type of sailor hat with a wide, flat peak is also known as square rig (this refers generally to a type of sailor uniform) cap or pork pie (not to be confused with the brimmed pork pie hat).