Why this weak, slow ship is the most important one in the fleet

She doesn't look like much. Weighing in at just under 19,000 tons, this ship doesn't have much in the way of firepower, either. She's relatively slow with a top speed of 23 knots. So, when you look at a Blue Ridge-class ship, you may wonder to yourself, "just what the heck is this thing's purpose?"

The short answer: She's the brains of the fleet. To be more precise, she's there to "provide command and control for fleet commanders" according to the United States Navy. But it's not entirely uncommon for a lesser-armed ship to take on such an important role.

Back in World War II, the auxiliary USS Argonne (AG 31) served as a flagship in the South Pacific for Admiral William F. Halsey. The transport USS MacCawley (APA 4) was used as the flagship for Admiral Richmond "Kelly" Turner until its loss in a friendly fire incident in 1943. The United States even converted a pair of amphibious ships, USS Coronado (APF 11) and USS LaSalle (AGF 3), to act as fleet flagships during the Cold War.

USS Blue Ridge (LCC 19) in the South China Sea.

(U.S. Navy photo by Mass Communication Specialist 2nd Class Jason Behnke)

The two-ship Blue Ridge-class, however, was built specifically for the task of enabling a fleet commander to handle his fleet. As a small, mobile command post, it is much less vulnerable to attacks from terrorists or enemies. There's a lot of ocean to hide in, so you have to search really hard to find it.

If worst comes to worst, the Blue Ridge does have some emergency firepower. For self-defense, the ship is outfitted with two Mk 15 Phalanx Close-In Weapon Systems. These 20mm guns are a last-ditch defense against incoming missiles, but this ship is intended to be well out of harm's way. Its primary weapons are its array of communications antennae, allowing commanders to handle operations across an entire theater if need be.

The reason for these ships in one photo: It provides a secure location for command and control, allowing admirals and generals to run operations.

(DOD photo by Cherie A. Thurlby)

The Blue Ridge-class command ships will be around for at least 20 more years, if not longer — not bad for ships that were commissioned nearly 50 years ago!

Learn more about the brains of the United States Navy's fleet in the video below.