SHIP'S MISSION: To embark, deploy and land elements of a Marine Landing Force in an assault by helicopter, landing craft, amphibious vehicles or by a combination of these methods.

LSD stands for Landing Ship, Dock. The ‘D’ is reference to a well deck, which is an open space running almost the entire length of the ship, allowing the aft part to sink up to ten feet in order to flood its well deck with water. How it works? The stern gate is lowered, and all or some of the ship's ballast tanks would be filled with sea water, causing the controlled lowering of the stern, allowing water to enter the well deck. Once the well deck is low enough, amphibious landing craft are launched or retrieved.

As a dry dock, boats would enter and be secured, the water in ballast tanks pumped back out resulting in the dry docking of the boat(s), and the stern gate lifted. LSDs also have a flight deck for helicopter operations, aviation refueling and fuel storage capabilities, one or two cranes, and multiple small boats.

Like all Naval ships, LSDs have evolved. The 55 years between the first and last LSD saw the length increase over 150’, vehicle storage capacity increase by almost 7,000 square feet, and ship displacement increase by over 8,100 tons. Original 3”/50 caliber gun mounts have been replaced with modern weapon systems, flight operations have expanded to include multiple landing spots for helicopters up to V-22 Osprey in size, and well decks are larger to accommodate the Navy’s newest amphibious assault landing craft. LSDs have always been able to berth, feed, and transport hundreds of fully equipped combat troops; the last LSD built can hold over 500.

The very first class of LSDs was the Ashland Class (LSDs 1-8), followed by the Casa Grande Class (LSDs 13-27), Thomaston Class (LSDs 28-35), Anchorage Class (LSDs 36-40), Whidbey Island Class (LSDs 41-48), and Harpers Ferry Class (LSDs 49-52). NOTE: LSDs 9-12 were delivered to the British Navy.

The last LSD commissioned was in 1998 and there are ten still active. The decommissioning in 2023 of LSDs 42, 44, 46, and 48 was blocked by congress. This puts in question the decommissioning and placing in reserve of LSDs 47, 49, 50, and 52 which were scheduled for 2024; LSD 51 in 2025; and LSD 45 in 2026.