BDE Destroyer Escorts to be transferred to Britain during World War II CG Destroyers loaned to the Coast Guard during 1924-1934 D Destroyer (prior to 1921) DD Destroyer (after 1921) DDC ASW Corvette DDE Destroyer converted to Fleet Escort DDG Guided Missile Destroyer DDH Destroyer with an assigned Helicopter DDK Destroyer, ASW (Submarine Killer) DDR Destroyer, Radar Picket DE Destroyer Escort, Escort or "Ocean Escort" DEC Destroyer Escort, Control (Amphibious Control) DEG Destroyer Escort, Guided Missile DER Destroyer Escort, Radar Picket DL Destroyer Leader (1920 to 1955) DL Frigate (after 1955) DLG Frigate, Guided Missile DLGN Frigate, Guided Missile, Nuclear Powered EDD Destroyer, Experimental Test Ship (before 2005) EDD Destroyer, Self-Defense Test Ship (after 2005) EDDE Experimental Escort Destroyer EDDG Guided Missile Destroyer, Experimental Test Ship FF Frigate FFG Guided Missile Frigate FFH Frigate with an assigned Helicopter FFR Radar Picket Frigate FFT Reserve/Training Frigate PE Patrol Escort PF Frigate or Patrol Frigate PFG Patrol Frigate, Guided Missile TB Torpedo Boat

The United States built her first torpedo boat Cushing (TB-1) in 1890 and her last Wilkes (TB-35) in 1902. Most of these were decommissioned or re-purposed prior to the start of World War I. The surviving Torpedo Boats were renamed on 01 August 1918 as "Coast Torpedo Boat #X" where "X" was a new numeric series, starting with # 1. This number was given to the former USS Foote (TB-3) which was now renamed as USS Coast Torpedo Boat # 1 (TB-3). Like the old pre-dreadnought battleships mentioned above, this renaming of torpedo boats was done in order to free up their names for new destroyers. All of these torpedo boats were decommissioned the following year and soon afterwards sold for scrap. As these boats were all gone prior to the 17 July 1920 redesignation, the Torpedo Boat designation went out of service and was not replaced with a new one. New small warships of about this size were now designated in the Patrol Vessel category.

The first USN destroyer was Bainbridge (D-1) which completed in 1902. The designation for all existing destroyers was changed from "D-X" to "DD-X" as part of the 20 July 1921 redesignation mentioned above. During prohibition, twenty-five destroyers were loaned to the US Coast Guard and these ships were redesignated as "CG-X" starting with USS Cassin (DD-43) which became CG-1 on 7 June 1924. Most of these destroyers were scrapped following their return to the USN after the end of prohibition but a few were retained and these few were given back their previous DD designation and hull number.

Following World War II, many Fletcher (DD-445), Allen M. Sumner (DD-692) and Gearing (DD-710) class destroyers were modified and given new, specialized missions as Fleet Escorts (DDE), Radar Pickets (DDR) and ASW submarine killers (DDK). The ASW destroyers (DDK) were redesignated as Fleet Escort destroyers (DDE) on 4 March 1950. All Fleet Escort destroyers (DDE) were reclassified as destroyers (DD) on 30 June 1962. Most radar picket destroyers (DDR) were reclassified as destroyers (DD) during the 1960s. One Fleet Escort destroyer USS Saufley (DDE-465) was reclassified as an Experimental Escort Destroyer (EDDE) on 1 January 1951 and then used as a test bed during the 1950s for sonar and ASW experiments. She was reclassified as a general purpose destroyer (DD-465) on 1 July 1962.

Faced with a growing Soviet submarine threat, several conversions of the Benson/Livermore classes to an ASW "corvette" (DDC) design were proposed for FY1955. This would have entailed removing one boiler and a five-inch gun so as to increase tankerage and ASW capabilities. Nothing came of these proposals and most of these ships remained decommissioned until they were scrapped in the late 1960s and early 1970s.

USS Gyatt (DD-712) was modified to carry a twin Terrier launcher and she was designated as DDG-712 on 1 December 1956. She was redesignated as DDG-1 on 23 May 1957. Her missile emplacement was later removed and her designation reverted back to DD-712 on 1 October 1962.

The "DL" designation meaning "Destroyer Leader" was originally created as part of the 17 July 1920 designation system revision. This designation was not assigned to any ship prior to 2 February 1951 when the ASW cruiser USS Norfolk CLK-1 was redesignated as DL-1 as described above. In addition, the new fleet destroyers of the Mitscher class, which were originally designated in the DD series as DD-927 to DD-930, were redesignated on 2 February 1951 as DL-2 to DL-5. This designation change was meant to indicate that these warships were significantly larger than those destroyers built during World War II yet still smaller than cruisers. As these warships were not really "leaders" in the sense of being equipped as destroyer flotilla leaders, the DL designation was reauthorized to mean "Frigate" on 1 January 1955.

The follow-on Farragut class frigates were originally to be an all-gun design and the first three ships of this class were designated as DL-6 to DL-8. The next three ships starting with USS Coontz were to a similar design but were given a Terrier missile launcher and were designated accordingly as DLG-1 to DLG-3. However, the Navy subsequently decided to equip the Farragut class with Terrier missile launchers and their designation was then changed to become DLG-6 to DLG-8 on 14 November 1956. USS Coontz and her sisters were renumbered in sequence starting with DLG-9 on that same date. As a result of these changes, all DL and DLG warships were in the same hull number series.

The Mitscher class frigates Mitscher (DL-2) and John McCain (DL-3) were converted to carry a Tartar missile launcher during the 1960s and they were then redesignated as missile destroyers DDG-35 and DDG-36, respectively, in 1968-69. As noted above in the cruiser section, on 30 June 1975 most Frigates were redesignated as CG and CGN with the same hull number as used previously, the exception being the Farragut DLG class which were redesignated as missile destroyers DDG-37 through DDG-46.

The designation "DE" was originally assigned to the Destroyer Escorts of World War II. The "DE" designation was changed to mean "Ocean Escorts" for those convoy escorts of the 1950s-1970s starting with the USS Dealey (DE-1006) class and ending with the USS Knox (DE-1052) class, but this was a seldom-used term. The DANFS entry for USS Knox herself describes her as "the prototype in a new class of destroyer escorts" while the Naval Vessel Register (NVR) currently lists all DE-designated ships as simply "Escort" including those built during World War II. As stated above, existing Guided Missile Escorts (DEG) were redesignated as Guided Missile Frigates (FFG) and those Escorts (DE) still in commission were redesignated as Frigates (FF) on 30 June 1975.

Some Edsall (DE-129) class destroyer escorts were converted to Radar Picket (DER) ships during the 1950s. They carried this designation during the rest of their careers, although none of them appear to have been used in that role after about 1960. As part of the 30 June 1975 reclassification program described above, two of these ships, USS Camp (DER-251) and USS Forster (DER-334) were redesignated as Radar Picket Frigates FFR-251 and FFR-334, respectively. These two ships had been transferred to the Republic of Vietnam during the 1970s. When that nation fell at the end of the Vietnam War, Camp escaped to the Philippines but Forester was captured on 30 April 1975 and so was not under USA control at the time of her redesignation two months later.

Three Destroyer Escorts (DE-698, DE-704 and DE-705) were converted to Amphibious Control Ships (DEC) in 1950-51 by adding extra communications gear, but they were all placed back into reserve by 1954 and the designation was abolished in 1957. The amphibious control role was taken over by the APD flagships.

The "PF" designation was originally used for World War II frigates of the Asheville (PF-1) and Tacoma (PF-3) classes. In the 1970s, it was proposed to designate what became the Oliver Hazard Perry (FFG-7) class as PF which would have then meant "Patrol Frigates." In the end, these ships were designated simply as "Frigates."

During the late 1960s and early 1970s, a series of design studies were made for the "next generation" of ASW and guided missile carrier escorts. These warship designs were given various interim designations, such as "DX" for the conventionally powered ASW destroyers, "DXG" for conventionally powered guided missile destroyers, "DXGN" for nuclear powered guided missile destroyers and "DG/Aegis" for an "austere" Aegis missile destroyer. These proposals coalesced around what eventually became the conventionally powered Spruance (DD-963) ASW destroyers and Ticonderoga (CG-47) Aegis missile cruisers. The nuclear powered version, which had grown considerably in size and was now known as a "Strike Cruiser" or CSGN and then later as the "CGN-42" class, was cancelled in the fall of 1978 although it was resurrected a few times until being cancelled once and for all in 1983.

A similar series of interim designations was used for new destroyer and cruiser designs during the early 2000s, respectively "DD-21" and "CG-21" until these temporary ones were replaced with the formal "DD(X)" and "CG(X)" designations. The first destroyer in the DD(X) series was christened as USS Zumwalt (DDG-1000). This meant that these ships are numbered in the DD series, rather than the DDG series, and it appears likely that the unused hull numbers DD-998 and DD-999 will not be assigned to any ship. As of this time (2019), no CG(X) cruisers have been funded or laid down.

As expected, the schedule delays and ballooning costs of the Zumwalt class destroyers has resulted in additional orders for Arleigh Burke DDGs and it is now expected that advanced versions of this class will continue in production for at least the next decade.

The DD designation went out of service when "the last destroyer" USS Cushing DD-985 was decommissioned on 21 September 2005. As noted above, the first US Torpedo Boat (TB-1) was also named Cushing.

In January 2015 the Navy announced that new ships in the Freedom (LCS-1) and Independence (LCS-2) classes would now be designated as Frigates (FF). Existing ships may be redesignated, but this was not certain at this time (2015).