How is jrotc different today than 100 years ago?

JROTC is different today than it was 100 years ago because JROTC used to be used as a source of enlisted officers for the military until it changed its role to teach morale leadership skills citizenship skills and educational skills. Sure it still teaches some things that it used by the military but it is mostly used to help make students in high school and college better citizens than they used to be.

Ship building industry , good luck : )