Colonial Marine Corps
From Battlestar Wiki, the free, open content Battlestar Galactica encyclopedia and episode guide
The Colonial Marine Corps is a branch of the Colonial Forces tasked with ground combat operations and ship-board security.
Galactica initially had about thirty Marines left, although there are no snipers among them (TRS: "Bastille Day"). This number increased drastically with the addition of the battlestar Pegasus to the Fleet.
Between "Pegasus" and "Exodus Part II", it is estimated that Galactica had at least 100 marines considering the arrival of Pegasus. The crew transfers might suggest some Marines from Pegasus were integrated into the crew of Galactica since there were Marines being trained aboard Pegasus (TRS: "Razor").
After Pegasus's destruction, a number of Marines are integrated into Galactica's crew. During a briefing between Colonel Tigh and Admiral Adama, Tigh says "A hundred Marines too weak to work, two hundred more about to drop", which implies that there are now at least 300 Marines, probably accounting for the Pegasus survivors (TRS: "The Passage").
A Marine's duties include guarding the CIC and the brig as well as other critical areas on the ship, and assisting the Master-at-Arms (TRS: "Litmus") and are part of Raptor boarding parties (TRS: "Bastille Day", "Kobol's Last Gleaming, Part II", "Resistance", "Pegasus"). Naturally, they are also responsible for repelling enemy boarding actions (TRS: "Valley of Darkness"). Admiral Adama's quarters are constantly under marine guard, and the same is true for President Roslin when she is aboard ship. A Marine is also tasked with serving Admiral Adama's food (TRS: "A Day in the Life").
Very few Marine officers appear to be stationed on Galactica; when they are shown on missions, usually Fleet officers command the Marine units. Crashdown's actions on Kobol (TRS: "Fragged") suggest that Fleet officers are cross trained in conducting ground operations. The only Marine officers shown so far are Lieutenant Terry Burrell (TRS: "Sacrifice") and an unnamed lieutenant in "Escape Velocity".
Marines are evidently untrained in crowd control, as the actions on the Scylla and Gideon demonstrate. In each of these situations Marines react with little discipline to enraged crowds (TRS: "Razor", "Final Cut"). Marines are also present enforcing an order restricting public congregation (TRS: "Escape Velocity").
Colonial Maries play a major part in the Battle of The Colony. They are apart , Assault 1, Assault 2, and Reserves. Unlike their normal patrol and guard duty's they seem to be very heavily armed and well equipped. With machine guns, extra ammo, Grenades, and Flight Suits. They also seem to have Call Signs or Code names for possible use over coms. They take heavy casualties with many of which prove to be fatal.
Only the ranks of the enlisted crew have been established in detail so far, but it is known that the rank of lieutenant exists. See military ranks for details.
Status Unknown after the Mutiny
Status Unknown after New Caprica
Real life costuming notes
The Colonial Marine Corps battle uniforms appear to be based on those of the U.S. Army's Delta Force or the counter-terrorist branch of the British Army's Special Air Service Regiment. Besides their black combat uniforms, the weapons and personal combat equipment of the Marines are similar to what today's police SWAT teams and anti-terrorist special forces units utilize.
To date, the Marines have appeared in either an all-black BDU (aboard ship) or an olive-drab/green BDU (planetside, as in "Lay Down Your Burdens, Part I"). There is evidence that the Colonial Marine Corps do utilize digital camouflage uniforms like the real-life United States Marine Corps with their MARPAT digital camouflage uniforms, but it appears that the wearing of digital camouflage uniforms are restricted to regular Colonial Marine Corps forces while the Marines serving as security personnel on the warships of the Colonial Fleet are issued solid-color combat uniforms in black, khaki, and olive-drab. One piece of evidence that the Colonial Marine Corps do utilize digital camouflage uniforms can be seen the in the episodes "Lay Down Your Burdens, Part I" and "Part II" when the rescue team that is deployed to Caprica have "woodland" digital camouflage backpacks on their backs. Furthermore, in one of the Razor Flashback episodes, two Colonial Marine medics are wearing "woodland" digital camouflage uniforms on Galactica's hangar deck. Digital camouflage is also used by the landing party on Kobol in "Home, Part II" (by both William and Lee Adama), as well as the Shore Patrol personnel in "Scattered". By todays standards the Marines are lightly armed. When Lee Adama is rescued by a Marine fire team when one of them fires a explosive round from his sidearms. He tells Lee the Centurions can only be destroyed with explosive round and that was their last one. If the fireteam had destroyed At least one Centurion that may emply that they carry only one explosive round. It is also seen that the Marines do not carry Gearnades other than a flash bang He That Believeth In Me. The Marines also appear not to have Armor plating in their combat vest and being that todays Marines mostly do have Armor plates in their Combat Vest.
To outfit the Marines, the show's costume department appears to use the following real-world items: