Milsurp After Hours

In 1664, Charles II decreed that a regiment of foot soldiers should be formed specifically for service aboard Royal Navy ships. The Act of Disbandment forbade the King from raising regiments for the Army, but the Navy was a different matter.

https://www.forces.net/services/royal-m ... ines-began

On US Navy ships the Marine detachment was often the police force onboard. The Navy crew probably considered them their natural enemy.