Young Curly Blonde Girl Posing In The Blue Studio With A Rope And A Sailor Cap

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).
Sailor cap was first introduced in 1811 as a part of the uniform in the Russian Navy (bezkozyrka, ru. бескозырка, non-peaked hat). It was a development of the peaked cap in application to marine conditions.
U.S. Navy and Bolivarian Armada of Venezuela sailors wear a unique white canvas hat with an upright brim, often referred to as a "Dixie cup" in reference to its similarity to the shape of a common disposable drinking cup. This hat was also worn by Polish Navy sailors before 1939—it was called "amerykanka" (not exactly pol. "American hat") or "nejwihetka" (derived from "Navy hat").