A ship class is a group of ships of a similar design.
A naval ship is a military ship, differentiated from civilian ships by construction and purpose. Generally, naval ships are damage-resilient and armed with weapon systems, though armament on troop transports is light or non-existent. Naval ships designed primarily for naval warfare are termed warships, as opposed to support or "auxiliary" ships.
Amphibious/Attack Transports were designed to sail to the site of amphibious operations carrying assault troops and support equipment. APAs had the capacity to hold a full battalion of troops. The APA disembarked troops with the ships own landing craft. The APA would then stand off the beachhead ready to evacuate troops, casualties, and prisoners of war. In order to carry out its primary mission APAs had to provide all facilities for the embarked troops including, berthing, messing, medical and dental care, and recreational facilities. All APAs in the Navy inventory on 1 January 1969 were redesignated as Amphibious Transports or "LPAs".
A total of 388 APA (troop) and AKA (cargo) attack transports were built for service in World War II in at least fifteen classes. Depending on class they were armed with one or two 5-inch guns and a variety of 40mm and 20mm anti-aircraft weapons.
Listed below are 17 classes comprising 248 ships in total.
Whereas Bayfield-class ships were literally hand-crafted, Haskell-class ships were mass-produced. The Haskells were not as good as the Bayfields but they were good enough.
USS Calvert (APA-32), a Bayfield-class APA
Attack Transport (APA) is a United States Navy ship classification.
With the entry of the United States into World War II, it was quickly realized that amphibious combat operations on hostile shores would be required, and that specialized ships would be needed for the purpose. The so-called "attack transport" ship type (hull classification symbol APA) was developed to meet this need. Attack transports were converted from standard transport vessels by being upgraded with extra firepower, and outfitted with a number of smaller integral landing craft (such as LCVPs and LCMs) with which amphibious assaults could be conducted.
Amphibious/Attack Transports were designed to sail to the site of amphibious operations carrying assault troops and support equipment. APAs had the capacity to hold a full battalion of troops. The APA disembarked troops with the ships own landing craft. The APA would then stand off the beachhead ready to evacuate troops, casualties, and prisoners of war. In order to carry out its primary mission, APAs had to provide all facilities for the embarked troops including, berthing, messing, medical and dental care, and recreational facilities.
Attack transports were equipped to carry landing craft and troops with which to carry out amphibious assaults. Because a troop transport carries less weight than a cargo ship, it was required that they be ballasted to compensate for the increased top weight from landing craft and landing craft davits with concrete in the bottom of the cargo holds in order to improve the ship's comfort, safety and performance.
Attack transports required a minimum cruising speed of 14 knots to keep up with fast invasion convoys, and they had more extensive communications equipment and anti-aircraft armament than ordinary transports. Most were converted from modern merchant ships.
A typical APA carried about 1,500 troops and 15-33 LCVPs and 2-4 LCMs with which to land them. It took about a dozen APAs to land a division.
USS Cavalier (APA-37), a Bayfield-class APA
The first attack transports began to enter service in 1942 and were built ad hoc from a host of different types. In the early 1940s, as the United States Navy expanded in response to the threat of involvement in World War II, a number of civilian passenger ships and some freighters were acquired, converted to transports and given hull numbers in the AP series. Some of these were outfitted with heavy boat davits and other arrangements to enable them to handle landing craft for amphibious assault operations.
As World War II went on, dozens of new construction merchant ships of the United States Maritime Commission's S4, C2, C3 and VC2 ("Victory") types were converted to attack transports.
The first class of attack transports to be built in substantial numbers was the Bayfield-class which began to enter service in 1943. (USS Elmore entered service on 25 August 1943).
Bayfield-class vessels were based on the large Type C3 passenger and cargo ship standard set by the US Maritime Commission. Originating in 1938, The C3 standard was designed to produce modern, good-quality cargo and passenger ships to replace the aging US merchant fleet, and which could also be readily converted into naval auxiliary vessels in the event of war. After the war broke out however, the need for shipping became so great that the US was forced to come up with designs that could be more quickly manufactured. Thus the C3-based Bayfield-class and its predecessors were eventually outnumbered by the Haskell-class which was based on the simpler Victory ship design.
Bayfield-class vessels were based upon the C3-S-A2 design standard. The basic design had to undergo a number of changes in order to meet the attack transport specification.
In order to accommodate the troops, two cargo holds amidships had to be converted into accommodation facilities. This was achieved by dividing each hold into three decks, and then building a number of passageways along each deck. Along both walls of each passageway, bunk-beds tiered five high were installed, and since space was still at a premium, each bunk was only thirty inches wide.
The troops were provided with their own galley and mess hall separate from that of the ship's crew, but they had no dining hall and used their own mess gear to eat. A sick bay and dental clinic were also provided. The troop commander had his own private cabin and office, which was fitted with a loudspeaker system from which he could directly address the men under his command. In order to keep the soldiers entertained during their long, crowded voyages, music and other entertainment could be piped to the troop compartments.
Since attack transports would be conducting operations off hostile shores, they had a greater requirement for armament than ordinary transports, particularly in regards to antiaircraft defense. The Bayfield-class vessels were well-outfitted in this regard. Each vessel was fitted with a pair of 5"/38 calibre dual purpose guns, one fore and one aft. The ships were also fitted with between two and four twin 40mm antiaircraft mounts (early examples came with two quad 1.1" gun mounts instead), plus two single 40 mm mounts and eighteen 20mm mounts as standard.
As the war progressed, the 20 mm cannon were found to be less effective than the 40 mm, and the later Gilliam and Haskell-classes dispensed with some of these mounts. The later classes also had only one 5-inch (130 mm) gun instead of two.
A total of 34 Bayfield-class vessels were produced between 1942 and 1944 - making the Bayfield-class the second most numerous attack transport class behind the Haskell-class. Bayfield-class vessels served in both the Atlantic and Pacific theaters of war. Some went on to see service in the Korean and Vietnam wars.
USS Renville (APA-227) was a Haskell-class attack transport that saw service with the US Navy in World War II, the Korean War and the Vietnam War.
Haskell-class attack transports (APA) were amphibious assault ships of the United States Navy created in 1944. They were designed to transport 1,500 troops and their combat equipment, and land them on hostile shores with the ships' integral landing craft.
The Haskell-class design, Maritime Commission standard type VC2-S-AP5, is a subtype of the World War II Victory ship design. 117 Haskell-class ships were launched in 1944 and 1945. The Victory ship design provided for a quicker and cheaper build than the more-complex Bayfield-class. Whereas Bayfield-class ships were literally hand-crafted, Haskell-class ships were mass-produced. The Haskells were not as good as the Bayfields but they were good enough.
The Haskells were very active in the World War II Pacific Theater of Operations, landing Marines and Army troops and transporting casualties at Iwo Jima and Okinawa. Ships of the class were among the first Allied ships to enter Tokyo Bay at the end of World War II, landing the first occupation troops at Yokosuka. After the end of World War II, most participated in Operation Magic Carpet, the massive sealift of US personnel back to the United States. A few of the Haskell-class were reactivated for the Korean War, with some staying in service into the Vietnam War.
The VC2-S-AP5 design was intended for the transport and assault landing of over 1,500 troops and their heavy combat equipment. During Operation Magic Carpet, up to 1,900 personnel per ship were carried homeward.
The Haskells carried 25 landing craft to deliver the troops and equipment right onto the beach. The 23 main boats were the 36 feet (11 m) long, LCVP. The LCVP was designed to carry 36 equipped troops. The other 2 landing craft were the 50 foot (15 m) long LCM (3), capable of carrying 60 troops or 30 tons (27 t) of cargo, or the 56 foot (17m) LCM. They also carried one gig.
The Haskell-class ships were armed with one 5"/38 caliber gun, twelve Bofors 40 mm guns (one quad mount, four dual mounts), and ten Oerlikon 20 mm guns.
Most of the Haskell-class ships were mothballed in 1946, with only a few remaining in service. Many of the Haskell-class were scrapped in 1973-75.
By the end of the 1950s, it was becoming clear that boats would soon be superseded by amphibious tractors (LVTs) and helicopters for landing combat assault troops. These could not be supported by attack transports in the numbers required, and new categories of amphibious ships began to replace APAs throughout the 1960s. By 1969, when the surviving attack transports were redesignated LPA (retaining their previous numbers), only a few remained in commissioned service. The last of these were decommissioned in 1980 and sold abroad, leaving only a few thoroughly obsolete World War II era hulls still laid up in the Maritime Administration's reserve fleet. The APA/LPA designation may, therefore, now be safely considered extinct.
It is easy to spot the difference between a Bayfield and a Haskell APA. From a side view, notice the ship's lines from the bow as it lowers to meet the main deck. The Bayfield-class has one swoop while the Haskell-class has two swoops.
A ship class is a pattern for construction, where the ships of a given class are essentially identical. The lead ship in a class provides the name for that class. Thus, the first ship in the Bayfield-class was USS Bayfield (APA-33).
USS Elmore (APA-42), a Bayfield-class APA.
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Lead Ship in Class
Commission date of lead ship