[dragoon500ly]

In recent posts, a unique Marine organization, the Defense Battalion, has been mentioned. The defense battalion originated in 1937
as a proposal to defend vulnerable American possessions in the Pacific. They would be armed with coast defense and antiaircraft guns and were to be the size of a reinforce battery or small battalion.

The first Defense Battalionwas organized in 1939. Their mission was to counter air attacks, hit-and-run surface ship raids and small landing parties. The full strength Defense "Battalion" were virtually regimental size and were commanded by a colonel. A money-tight Congress was the reason that they were called battalions. Their large size allowed them to be split between islands in the early days.

The typical TO&E in 1939-42 was:

HQ & Service Battery
Coast Defense Group
HQ & Service Battery
2 or 3 Coast Defense Batteries, each armed with two 5-inch/51 rifles.
Antiaircraft Group
HQ & Service Battery
Searchlight Battery with eight 60-inch Sperry searchlights
3 Antiaircraft Batteries, each with four M-3 3-inch AA guns
Machine Group
HQ & Service Battery
2 Machine Gun Batteries, each with 12 M-1917A1 .30-cal HMGs
2 Machine Gun Batteries, each with 12 .50-cal water-cooled HMGs
Provisional Marine Company, with 2 60mm mortars, 2 81mm mortars and 2
37mm M-1918 infantry guns (not always present)

The 1943-44 Defense Battalion TO&E is:
HQ & Service Battery
Seacoast Artillery Group
HQ & Service Battery
2 Gun Batteries, each with four M-1A1 155mm guns
Antiaircraft Group
HQ & Service Battery
Searchlight Battery with 8 60-inch Sperry searchlights
4 Antiaircraft Batteries, each with 4 M-1 90mm AA guns
Special Weapons Group
HQ & Service Battery
Antiaircraft Battery with 6 M-1 40mm AA guns
2 Antiaircraft Batteries, each with 6 Mk4 20mm AA guns
Provisional Marine Company with 2 60mm mortars and 2 81mm mortars
Tank Platoon with 5-8 M-3/M-5 light tanks.

And just to prove that the TO&Es don't always have any contact with reality...

On December 7, 1941, the 1st Defense Battalion was split into four detachments:

Rear Echelon, Pearl Harbor: 261 men with 10 5-inch/51 rifles, 8 3-inch AA
guns, 50 .50-cal HMGs and 50 .30-cal HMGs.

Wake Island Detachment: 422 men with 6 5-inch/51 rifles, 12 3-inch AA guns,
18 .50-cal HMG and 30 .30-cal HMGs.

Johnston Island Detachment: 162 men with 2 5-inch/51 rifles, 4 3-inch AA
guns, 8 .50-cal HMGs and 8 .30-cal HMGs.

Palmyra Island Detachment: 158 men with 4 5-inch/51 rifles, 4 3-inch AA
guns, 8 .50-cal HMGs and 8 .30-cal HMGs.

The large number of weapons held by the Rear Echelon included spares and those awaiting shipment to the other detachments as well as a single
7-inch/45 rifle waiting for shipment to Midway.