Used to protect American islands in the Pacific as well as on the US coast, these border patrol troops were tasked with defending important Navel vessels and harbors. These soldiers were also often capable sailors and could easily preform the duties of a US sailor or other Navel military position. Many of these troops were on guard duty at Pearl Harbor when the Japanese attack started. However, in times of war, these units were often replaced with more conventional and experienced groups such as the marines.