For decades, older sailors told incoming sailors that the 13 buttons on the front of the bell bottoms represented the original 13 colonies. The myth was so commonplace , it actually had to be excised from Navy history texts.
Sailors originally used a drawstring to hold up their pants, but threw away the drawstrings in 1864 when a new version of the bellbottoms was designed with seven buttons across the top holding the crotch flap. With a nod toward comfort in more tropical climates, the Navy elongated the flap(also called a broadfall) in 1897, and two buttons were added to each side, now totalling 11. But as Navy men grew broader-possibly thanks to improvement in nutrition-the flap needed to grow longer. So in 1905 more buttons were added, creating those 13 buttons. Why buttons instead of zippers? Beacause buttons are much easier to replace on the fly, and early zippers may have corroded in the salty weather.
"reprinted from Uncle John's Bathroom Reader Salutes the Armed Forces"
BTW if your looking for a book on the more obscure history of all the armed forces this is a great read.
After WW II the girls were taking the blue pants and cutting them to their length and opening the leg. Then sewing up the front and back. Some time they would put in an extra piece to make a big pleat. Looked great and fit great with the laces in the back.
