Landing Ship, Dock (LSD)
Amphibious Transport, Dock (LPD)
The Landing Ship, Dock (LSD) evolved from WWII designs to carry more and larger landing craft, with the Harper's Ferry/Whidbey Island-classes capable of LCAC operations. The US Navy requires a minimum of 6 or 7 LCACs to support an ESG. The Amphibious Transport, Dock (LPD - Landing Platform Dock) was developed primarily to support helicopter operations. The LPD is also the main platform for the new AAAV. LSDs generally could land more cargo and heavy equipment, while LPDs transport more Marines.
Landing Ship, Dock (LSD) and Amphibious Transport, Dock (LPD) have a well deck and a ballast system which allows boats to be dry docked. The term "dock" is somewhat confusing, since it might be imagined that these ships are intended to land at a dock, or transport to a dock. A dock is a water-side site at which ships tie up in order to discharge and take in cargoes conveniently and expeditiously. It is typically a basin constructed for this purpose, surrounded by quay walls. But a graving dock (or dry dock) is a dock which can be sealed off by gates, and the water removed. This allows work to be done on the parts of a ship's that are normally under water. The term "graving" was more often used to denote the cleaning of a ship's bottom. The docks in the Landing Ship, Dock (LSD) and Amphibious Transport, Dock (LPD) are internal to the ship, and allows boats to be dry docked for transport, loading and maintenance.
The amphibious ship's well deck that can sink up to 10 feet in order to flood its well deck with water. The stern gate is lowered and ballast tanks are filled with water, causing the controlled lowering of the aft (back) end of the ship and allowing water to enter the landing craft docking well, generally known as the well deck. Once the well deck is low enough to allow boats into the well deck, the boats are floated and secured. The water in tanks are pumped back out, resulting in the dry docking of the boat(s). The stern gate is lifted and the ship is ready to steam to its next mission.
Dock Landing Ships (LSD) support amphibious operations including landings via Landing Craft Air Cushion (LCAC), conventional landing craft and helicopters, onto hostile shores. These ships transport and launch amphibious craft and vehicles with their crews and embarked personnel in amphibious assault operations. Amphibious Transport Docks (LPD) transport and land Marines, their equipment and supplies by embarked landing craft or amphibious vehicles augmented by helicopters in amphibious assault. These versatile ships perform the mission of amphibious transports, amphibious cargo ships and the older LSDs by incorporating both a flight deck and a well deck that can be ballasted and deballasted to support landing craft.
Current USN Amphibious Ships interface with various small landing craft. A well deck is an interior space running from the transom up to several hundred feet forward. Its deck is near the waterline of the ship and it has sufficient height to the deck overhead to operate all of the current landing craft. The Landing Craft Air Cushion (LCAC) interfaces with the Amphibious Ship using a dry well deck. This requires no ballasting of the amphibious ship. Non-air cushion landing craft, like LCU and LCM 8 require a well deck that is sufficiently submerged for these landing craft to float in / out of the well. This requires the use of substantial hull volume outside the well deck space for seawater ballast tankage to sink the ship to provide the necessary water depth over the well deck. The well provides a relatively protected environment for the landing craft to conduct vehicular, pedestrian, and break bulk cargo operations between the two vessels, but well deck operations are typically limited to Sea State 3 as defined by STANAG 4194. In addition, the well deck takes an enormous amount of hull volume and greatly complicates the bulkhead configuration to provide adequate damage stability.
Launching Amphibious Assault Vehicles (AAV) is one of the primary functions of a dock landing ship. It's a critical operation that requires precision and accuracy among every crewmember involved in each launch and recovery. After a successful launch in near perfect seas, the AAV's return to the well deck, where each will receive a fresh water wash down. Entering the well deck is a little trickier than departing, due to water current.
When Marines talk about taking a beach during amphibious assault missions, it is often from the versatile Landing Ship Dock (LSD). These amphibious transports are used to sea-base, transport and land Marines and their equipment. They do that via embarked landing craft and are augmented by helicopters or airplanes operating from Amphibious Assault Ships. The LHA-1 can ballast 12,000 tons of seawater for trimming the ship to receive and discharge landing craft from the well deck. The assault support system aboard a LHD-1 Wasp class ship coordinates horizontal and vertical movement of troops, cargo and vehicles. Monorail trains, moving at speeds up to 600-feet-per-minute, transport cargo and supplies from storage and staging areas throughout the ship to a 13,600-square foot well deck, which opens to the sea through huge gates in the ship's stern. There, cargo, as well as troops and vehicles, are loaded aboard landing craft for transit to the beach. Cargo is transferred to waiting landing craft docked within the ship's 266 foot long, well deck. The LCAC air cushion landing craft can "fly" out of the dry well deck, or the well deck can be ballasted down for conventional craft to float out on their way to the beach. Simultaneously, helicopters are brought from the hangar deck to the flight deck by two deck-edge elevators, and loaded with supplies from three massive cargo elevators.
Supplementing the big deck is an Amphibious Transport, Dock (LPD) and a Dock Landing Ship (LSD). The LPD transports and lands Marines, their equipment, and supplies by embarked landing craft or amphibious vehicles, augmented by helicopters in amphibious assault; LSDs support amphibious operations on a hostile shore via LCAC, conventional landing craft and helicopters.
LPD Landing Platform Dock
LPD stands for Landing Platform Dock although the ship is usually referred to as an Amphibious Transport Dock (LPD). Amphibious transport docks, both the 15 LPDs in previous ship classes and the San Antonio class, each will have a well deck in the after part of the ship. The ship will ballast her stern to either completely flood the well deck for launching and recovering conventional landing craft or only partially for Expeditionary Fighting Vehicles. These will egress or enter when the stern gate is opened. The ship then deballasts and operates with a dry well. The well deck is not flooded for LCAC, air cushion landing craft operations. Well deck operations may be conducted pierside, at anchor, or at sea while moving through the water.
Traditionally, the ships of the LPD 1 and LPD 4 class ships were named for cities named for explorers and historical figures e.g. Raleigh, LaSalle, Austin, etc. For the LPD 17 class, Secretary of the Navy John H. Dalton started a revised tradition, naming the lead ship San Antonio in 1996 after the city in Texas. To date most of the ships have followed this naming pattern with five named for cities - San Antonio, New Orleans, Green Bay, San Diego, and Anchorage; one named for a National Park, Mesa Verde; one named for a state, New York; one named for a city and county, Arlington; and one named for a county in Pennsylvania, Somerset. The LPD-4 Austin class, the ships of which are named after cities which have been named for early explores of the United States. The LPD-4 has a large flight deck and a well deck and is designed to transport, launch and control embarked helicopters and amphibious assault vehicles and other waterborne craft.
In the 21st Century, LPD 17 class performs more than amphibious missions, and serve as more than a transport for the landing forces. The LPD 17 has an upper stern gate that weighs over 20 tons and a lower stern gate that weighs 53 tons. They are about 78 feet wide and enclose an opening that is about 35 feet high. When opened, these gates provide ample room for launching or recovering LCACs (landing craft, air cushion), an LCU (landing craft utility) or amphibious vehicles such as the Marine Corps' Advanced Amphibious Assault Vehicle. The ship's well deck and vehicle storage can carry both landing craft and amphibious vehicles and ballast/deballast as necessary.
LSD Dock Landing Ship
The United States Navy Dock Landing Ships (LSD) support amphibious operations including landings via Landing Craft Air Cushion (LCAC), conventional landing craft and helicopters, onto hostile shores. These ships transport and launch amphibious craft and vehicles with their crews and embarked personnel in amphibious assault operations. The Landing Ship Dock also provide docking and repair services for LCACs and for conventional landing craft.
The Navy thought so much of the capabilities of the LSD that in the early 1950s it decided to build a new class of eight ships.The lead ship of the class, the USS Thomaston (LSD-28), was launched February 9, 1954. These ships sported redesigned superstructures as well as sleeker and more eye pleasing hull lines. This class could be identified from the earlier ships in that its ship had their main lifting cranes and smoke stacks offset from one side to the other.
The next step was the Anchorage-class ships, first launched in 1969. They can embark 302 troops and have extensive storage facilities, including 1,400 cubic feet for cargo and ammunition stowage and 8,400 square feet (15,200 square feet on board the LSD 36M ships) for vehicle storage. Their flight decks have one helicopter spot, and they can carry two or three LCACs in their well decks. The LSD 36s possess limited medical facilities, but they can serve a casualty receiving and treatment ship when augmented.
By the late 1980s most of the Thomaston class had been decommissioned and placed in inactive reserve status. The LSD-41 class was intended to replace the older LSD-28 Thomaston class. LSD 41 was designed specifically to operate LCAC vessels. It has the largest capacity for these landing craft (four) of any U.S. Navy amphibious platform. It will also provide docking and repair services for LCACs and for conventional landing craft. The Whidbey Island-class introduces significant improvements with updated communications, combat systems, 20- and 60-ton cranes, expanded repair shops, two helicopter landing spots, complete medical and dental facilities, automated computer-based logistic support and an impressive engineering plant that gives the Whidbey Island an excellent capability for self-sufficient operations.
The design of the Harpers Ferry (LSD 49)-class dock landing ship is similar to that of the LSD 41-class, with ships of both classes sharing the same general dimensions and propulsion plant. The major difference between the two is the shorter well deck in the Harpers Ferry class, which was adopted to allow greater vehicle stowage and cargo storage. This modification reduces the number of LCACs that these ships can carry from four to two. Otherwise, the LSD 49s can embark 454 troops and have extensive storage facilities - 50,700 cubic feet for cargo and ammunition and 16,900 square feet for vehicles. Each of these warships also have two helicopter deck spots.
Well Deck Certification
Well Deck Certification is part of the basic phase to prepare the ship in the mission of loading, transporting and landing troops and their equipment. The deck department needs to make sure the well deck and all the markings were painted. They also needed to make sure all the lighting and ventilation were operational.
While there are degrees of uncertainty and risk inherent in peacetime military operations, they are compounded during battle. Navy successes are based on balancing those risks with taking decisive action to complete a mission, whether routine or during combat. There is no such thing as a totally risk-free operation. Well-deck operations are no different. Whether taking place while pierside, at anchor, or underway, wet-well operations are potentially dangerous for Sailors and Marines involved, and to the amphibious craft and equipment associated with the evolution. Well-deck ballasting, craft-launching, and retrieval all require precise coordination allowing for virtually no human error or equipment failure.
Operational risk management--dealing with risks associated with specific operations, hazard assessment, risk decision-making, and implementing risk controls--therefore plays a critical role in successful, mishap-free well-deck ops. It is therefore imperative that during Condition 1A-flooding the well deck with sea water for well-deck loading or unloading and the moving of amphibious vehicles in the well deck-all involved Sailors and Marines involved must be aware of the people, equipment, and activity around them. They immediately must report to the chain of command any unsafe action or malfunctioning gear. It's called situational awareness and includes all Condition 1A personnel wearing required battle dress and PPE.
Familiarity with key well-deck operational terms is also a must -- the terms are listed below.
- Ballast - Adding water to ballast tanks to increase a ship's draft (lowering the stern to flood the well deck).
- Alive - The movement of a craft when the minimum depth required for floating a craft is reached; the craft is no longer grounded on the bottom of the well deck.
- Depth at the sill - Depth of water at extreme aft section of the well deck.
- Dry well - A condition where there is no water in the well deck.
- Grounded - When a craft's hull comes to rest on the well deck.
- Sill - The extreme aft portion of the well deck.
- Green well - When preparations in the well deck are completed and craft entry or exit is authorized. As soon as Green Well is given each AAV will make its approach into the well deck.
- Red well - When conditions in the well are not conducive to safe operation or craft are prohibited from entering or departing the well.
A thorough brief should be given to all Condition 1A participants before well deck operations begin. The brief must establish beyond a doubt that all crew members who will be involved in any manner with Condition 1A fully understand their specific watch stations and individual responsibilities. The brief should also make sure all involved understand the risks of Condition 1A operations and how those risks are going to be controlled. By adhering to those established risk controls, Sailors conducting well-deck operations will complete their mission successfully and protect Navy people and equipment--Navy leaders' goals in both war and peace.
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