This video takes a look at U.S. Navy Landing Force Rifle Squads from 1943 and 1950-60. These were ad hoc details of Navy sailors pulled from their duties onboard their ships to form landing parties. Special attention is paid to the standardized landing force aboard 2100-ton destroyers during WWII. During the 1950s, the structure was more akin to a lighter U.S. Marine Corps unit, with up to battalion-sized units able to be formed from several ships.
Here is a graphic representation of the World War II squad aboard a Fletcher-class destroyer: