BRP Rajah Humabon (PS-11)

The BRP Rajah Humabon (PS-11) is a former destroyer escort of the United States Navy and a former frigate of the Philippine Navy. It was the last World War II-era destroyer escort/frigate active in its fleet, and one of the oldest active warships in the world, until 15 March 2018 when it was formally decommissioned after 75 years. She was one of three ex-USN Cannon-class destroyer escorts that served the Philippine Navy, the others being BRP Datu Sikatuna (PF-5/PS-77) and BRP Datu Kalantiaw (PS-76).

Philippine Navy PF-11 at Balikatan 2010
BRP Rajah Humabon (PS-11)
United States
Name: Atherton
Ordered: 1942
Builder: Federal Drydock & Shipbuilding Co.
Laid down: 14 January 1943
Launched: 27 May 1943
Commissioned: 29 August 1943
Decommissioned: 10 December 1945
Struck: 15 June 1975
Fate: Transferred to JMSDF in 1955, reverted to US Navy in 1975. Transferred to Philippine Navy in 1976.[1]
Name: Hatsuhi
Operator: Japan Maritime Self-Defense Force
Commissioned: 1955
Decommissioned: 1975
Fate: reverted to US Navy in 1975.
Name: Rajah Humabon
Namesake: Rajah Humabon was the native chieftain of Cebu in the Philippines at the time of Ferdinand Magellan's arrival in the archipelago in 1521.
Operator: Philippine Navy
Acquired: 23 December 1978
Commissioned: 27 February 1980
Recommissioned: January 1996
Decommissioned: 15 March 2018
  • BRP Rajah Humabon (PF-6) - 28 June 1980[2]
  • BRP Rajah Humabon (PF-11) - January 1996
  • BRP Rajah Humabon (PS-11) - April 2016
Homeport: Naval Base Cavite
Status: Decommisioned
General characteristics
Class and type: Datu Kalantiaw class (Cannon class)
Type: Destroyer Escort / Frigate
Displacement: 1,390 tons standard, 1,620 tons full load
Length: 306 ft (93 m)
Beam: 36.66 ft (11.17 m)
Draft: 8.75 ft (2.67 m)
Installed power: 6,140 hp (4,580 kW)
  • 2 × GM-EMD 16-645E7 (Turbo) Main Diesel Engines[3]
  • 2 × GM-EMD 8-268A Auxiliary Diesel Engines with 200 kW Generator
  • 1 × GM-EMD 3-268A Auxiliary Diesel Engine with 100 kW Generator
  • 2 × shafts
  • 18 knots (33 km/h) sustained maximum[4]
  • 21 knots (39 km/h) tops[4]
  • 6,000 nmi (11,000 km) at 14 knots (26 km/h)
  • 10,800 nmi (20,000 km) at 12 knots (22 km/h)[3]
Complement: 165
Sensors and
processing systems:
  • Raytheon AN/SPS-64(V)11 Surface Search and Navigational Radar[5]
  • Furuno navigation radar
  • AN/SQS-17B Hull mounted Sonar[3]
  • Mk.52 GFCS with Mk.41 Rangefinder for 3-inch (76 mm) guns[3]
  • 3 × Mk.51 GFCS for 40 mm guns[3]


United States Navy

Atherton 1
as USS Atherton c. 1945

Commissioned in the US Navy as the USS Atherton (DE-169) in 1943, she was mostly assigned at the Atlantic theatre doing patrols and anti-submarine missions. She was credited of having destroyed a German U-boat, U-853 off the coast of Rhode Island, on 9 May 1945. She served in the Pacific theatre in the middle of 1945 until she was decommissioned and placed in reserve on 10 December 1945. For her service during World War II, she was awarded with one battle star.[6]

Japan Maritime Self-Defense Force

as JMSDF Hatsuhi c. 1967

She was transferred to the Japanese government as JDS Hatsuhi (DE-263) on 14 June 1955. Together with her sistership JDS Asahi (DE-262), they became one of the first warships of the newly organized Japan Maritime Self-Defense Force. As newer ships became available to the JMSDF, both ships were decommissioned and returned to the US Navy in June 1975.[5][6][7]

Philippine Navy

BRP Rajah Humabon (PF 11)
BRP Rajah Humabon c. 2009

Remained laid-up in Japan, she was transferred to the Philippine government on 13 September 1976[8] and was Transferred as an Excess Defense Article on 23 December 1978.[3][5] As a Philippine Navy ship, she was named RPS Rajah Humabon (PS-78), and was towed to South Korea for an extensive refit and modernization in 1979.[3] During this period South Korea also turned over 2 of their own ex-USN Cannon class ships to the US Navy in 1977, namely the Kyong Ki (DE-71) / USS Muir (DE-770) and Kang Won (DE-72) / USS Sutton (DE-771). These were also turned-over by the US to the Philippine government, which were later on cannibalized for use as parts hulk to upgrade and repair the Rajah Humabon and her sistership Datu Sikatuna, and provide both ships with additional guns and improved machinery.[9][10]

With these upgrades, she was formally commissioned to the Philippine Navy on 27 February 1980,[3] and formed the backbone of the Philippine Fleet together with 2 of her sister ships and other ex-US Navy destroyer escorts. She was renamed and reclassified as BRP Rajah Humabon (PF-6) effective 23 June 1980,[2] now using the "BRP" ship prefix in lieu of "RPS" and following a new standard classifying it as a "Frigate", and served until 1993 when she was retired. But due to pressing needs, she was later called back into service in 1995 after being overhauled at the Cavite Naval Dockyard by Hatch & Kirk Inc., and was formally recommissioned in January 1996 as BRP Rajah Humabon (PF-11) with a new hull number.[5]

Another minor refit between 1995 and 1996 saw changes in the ship's weapons, sensors and engine systems. Her anti-submarine weapons and equipment were removed due to lack of spare parts. The removed equipment includes the EDO SQS-17B hull-mounted sonar, a Mk.9 depth charge rack, six Mk.6 depth charge projects aft and a Hedgehog Mk.10 anti-submarine projectors forward, as well as Mk.38 anti-submarine torpedoes in two triple tube amidships.[5][11] The loss of these items totally removed her anti-submarine warfare capabilities, which was outdated by modern standards. But it was reported in 2005 that her fore Hedgehog ASW is still operational, together with her 8 K-gun Mk6 depth charge projectors and SQS-17B sonar,[3] although recent photos do not show the depth charge projectors on its usual location.

She had been experiencing hull problems, but was repaired with the assistance of the crew of the US Navy's ship USS Salvor during CARAT 2002 dive training operations held in Manila Bay.[11][12]

Additional electronic upgrades were made, including the installation of a Furuno Satellite Communication system and a mast-mounted FLIR package.[11][13]

The ship's code designation was changed based on a new classification, name, number and categorization of PN ships, crafts, aircraft, and ground equipage dated April 2016. Based on this change, the ship's designation was changed from PF-11 to PS-11.[14]

As of May 2010 she was part of the Philippine Navy contingent for the RP-US Balikatan 2010 exercises,[15] and continued to operate from the Philippine Navy's main naval base in Cavite and visits the Navy Headquarters in Manila. She was assigned to the Patrol Force of the Philippine Fleet.[16]

It then operated as a ceremonial ship to welcome foreign ships docking in Manila Bay. It was decommissioned in March 15, 2018 and is planned to be part of the Philippine Navy museum in Sangley Point.[17]

Technical details


Although fairly well-armed, most of her weapon systems are manually operated and are of World War II origin.

The three Mk.22 3"/50 caliber guns, the ship's primary weapons, have a range of up to 14,600 yards (13,400 m) and are also capable of being used as limited anti-aircraft weapon. The guns were directed by a Mk.52 gun fire control system with a Mk.41 rangefinder, but this appears to be non-operational.

She also carries a total of three twin Mk.1 Bofors L/60 40 mm anti-aircraft guns directed individually by Mk.51 gun fire control system, six Mk.4 20 mm Oerlikon cannons, and four M2 Browning 50 caliber machine guns.[5][11]

All anti-submarine weapons were removed as of 1996.[11]


The ship is powered by two EMD 16-645E7 turbo-blown diesel engines with a combined power of around 6,140 bhp (4,580 kW) driving two propellers. The main engines can propel the 1,620 ton (full load) ship at a maximum speed of around 18 knots (33 km/h). It has a range of 6,000 nautical miles (11,110 km) at a speed of 14 knots (26 km/h).[3] It replaced the original four EMD 16-278A diesel engines during the ship's overhaul in 1996.[18]


The ship is equipped with a Raytheon AN/SPS-64(V)11 short range surface search and navigation radar[5] and a Furuno navigation radar, replacing the SPS-5 surface search radar and the RCA/GE Mk.26 navigation radar.[3] Previously equipped with an EDO AN/SQS-17B hull-mounted sonar, it is said to be deleted in 1996 due to lack of spare parts and obsolescence[11][19] although it was reported to be still present in 2004.[3]

Notable Operations


On 17 June 2011 the Rajah Humabon was sent for patrols around the Scarborough Shoal after China announced that its biggest maritime patrol vessel, the Haixun 31, will be sent to the area on its way to Singapore.[20][21]


On 2 February 2000, the Rajah Humabon fired warning shots at two Chinese fishing boats near Scarborough Shoal. According to Navy chief Vice Admiral Luisito Fernandez, the Rajah Humabon was forced to fire warning shots to avert a collision with two Chinese fishing boats and only after the Chinese boats refused to respond to radio contact, loudspeaker, sirens, and flashing lights.[22]

On 22 June 2002, Rajah Humabon together with BRP Rizal visited Shanghai, China for a goodwill visit.[23]


The Rajah Humabon, together with BRP Leopoldo Regis (PG-847), BRP Dagupan City (LC-551), BRP Artemio Ricarte (PS-37), USS Essex (LHD-2), and USS Tortuga (LSD-46) were part of the naval component of the US-RP Balikatan 2009 bi-lateral exercises held in April 2009.[24]

Again Rajah Humabon, together with BRP Dagupan City (LC-551), and BRP Apolinario Mabini (PS-36), USS Essex (LHD-2), and USS Denver (LPD-9) were part of the naval phase of the US-RP Balikatan 2010 (BK10) bi-lateral exercises held in March 2010.[25]

On 14 to 16 August 2012, the Naval Forces Northern Luzon (NFNL) conducted a small-scale Naval Exercise code-named SAGEX 02-12 at the waters of South China Sea. BRP Rajah Humabon together with BRP Gregorio del Pilar and BRP Liberato Picar participated under Naval Task Force (NTF) 11. The exercise includes patrol, simulated tracking of targets and interdiction and capped by live firing exercises.[26]

Rajah Humabon, together with BRP Gregorio del Pilar participated in the sea phase exercises with the US Navy during the Balikatan 2013 from 5 to 17 April 2013.[27]

Notable Popular Culture

  • BRP Rajah Humabon was among the Philippine Navy ships who battled invading People's Liberation Army - Navy ships in Dale Brown's 1991 novel Sky Masters. In this novel, she was classified as a PF class frigate, and was equipped with a four-shot Mk141 Harpoon missile launcher.[28]


PF-11 051908 1

BRP Rajah Humabon (PF-11) anchored at Manila Bay on May 19, 2008

US Navy 090421-N-0120A-206 The forward-deployed amphibious assault ship USS Essex (LHD 2), center, steams in formation

BRP Rajah Humabon, together with Philippine & U.S. Navy ships during naval phase of Balikatan 2009 bi-lateral exercises held in April 2009

US Navy 090421-N-9950J-022 U.S. Navy and Armed Forces of the Philippines Navy ships are underway during exercise Balikatan 2009

BRP Rajah Humabon during naval phase of Balikatan 2009 bi-lateral exercises, April 2009.

Balikatan 2009-057

The forward-deployed amphibious assault ship USS Essex (LHD 2) leads ships formation during photo exercise (PHOTOEX) with Philippines Navy ships during Balikatan 2009 (BK09)

US Navy 100314-N-0120A-659 U.S. Navy ships and The Republic of Philippines navy ships cruise in formation while taking part in exercise Balikatan 2010 (BK 10)

BRP Rajah Humabon (far right) together with other Philippine and US Ships during Balikatan 2010 sea-phase exercises (BK10)

See also



  1. ^ NavSource Online: Destroyer Escort Photo Archive. USS Atherton (DE 169).
  2. ^ a b Philippine Navy Information Manual 1995 - Adoption of Pilipino Translation of "Bapor ng Republika ng Pilipinas"
  3. ^ a b c d e f g h i j k l m n Saunders, Stephen: Jane's Fighting Ships 107th Edition 2004-2005. Jane's Information Group Ltd, 2004.
  4. ^ a b c d "PS/PF Datu Kalantiaw Class Specifications". Retrieved 18 June 2014.
  5. ^ a b c d e f g Wertheim, Eric: The Naval Institute Guide to Combat Fleets of the World 15th Edition, page 550. Naval Institute Press, 2007.
  6. ^ a b Dictionary of American Naval Fighting Ships. "Atherton" page.
  7. ^ Dictionary of American Naval Fighting Ships. "Amick" page.
  8. ^ "USS Atherton (DE-169)". Retrieved 2011-11-06.
  9. ^ Dictionary of American Naval Fighting Ships. "Muir" page.
  10. ^ Dictionary of American Naval Fighting Ships. "Sutton" page.
  11. ^ a b c d e f Manokski's ORBAT @ Hueybravo. BRP Rajah Humabon page.
  12. ^ Faceplate Vol.7 No.1, April 2003 "USS Salvor (ARS 52)" page.
  13. ^ Jane's Fighting Ships 105th Edition 2002-2003.
  14. ^ 3 Japanese navy ships arrive in Manila
  15. ^ Philippine Navy Gallery Send Off Ceremony of Sailors and Marines to Balikatan 2010.
  16. ^ Philippine Fleet Official Website. Commissioned ships and crafts Archived 15 July 2012 at
  17. ^ Mangosing, Francis (15 March 2018). "PH Navy's oldest warship retires from service". Philippine Daily Inquirer. Retrieved 15 March 2018.
  18. ^ Philippine Panorama - 26 November 1995 Repowering Old Ships To Make Them Good As New by Randy V. Urlanda
  19. ^ Friedman, Norman: The Naval Institute Guide to World Naval Weapons Systems 1997-1998, page 628. US Naval Institute Press, 1997.
  20. ^ "Largest warship ng Philippine Navy, magpapatrolya sa Scarborough Shoal". Bombo Radyo Philippines. 2011-06-16. Retrieved 2011-06-20.
  21. ^ "Biggest Phl warship on patrol in Spratlys". (The Philippine Star). 2011-06-17. Retrieved 2011-06-20.
  22. ^ South China Tensions Promote Discussions on a Code of Conduct.
  23. ^ Seawaves Magazine, June 2002. Warships Port Visit.
  24. ^ US Navy News Balikatan 2009.
  25. ^ Commander US 7th Fleet Balikatan March Imagery.
  26. ^ Naval Forces Northern Luzon. "NAVAL FORCES NORTHERN LUZON CONDUCTS NAVAL EXERCISE". Philippine Navy. Retrieved 2012-08-21.
  27. ^ Asianet (2013-04-09). "Balikatan to make PN, USN more 'interoperable'". GlobalPost International News. Retrieved 2013-04-18.
  28. ^ Brown, Dale: Sky Masters ISBN 978-1-55800-915-8

External links

Cannon-class destroyer escort

The Cannon class was a class of destroyer escorts built by the United States primarily for ocean antisubmarine warfare escort service during World War II. The lead ship, USS Cannon, was commissioned on 26 September 1943 at Wilmington, Delaware. Of the 116 ships ordered, 44 were cancelled and six were commissioned directly into the Free French Forces. Destroyer escorts were regular companions escorting the vulnerable cargo ships.

With the decommissioning of the Philippine Navy's BRP Rajah Humabon (PS-11) in March 2018, HTMS Pin Klao (DE-1) of the Royal Thai Navy, remains the only confirmed commissioned ship of this class as of 2018.


In naval terminology, a destroyer is a fast, maneuverable long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller powerful short-range attackers. They were originally developed in the late 19th century by Fernando Villaamil for the Spanish Navy as a defense against torpedo boats, and by the time of the Russo-Japanese War in 1904, these "torpedo boat destroyers" (TBDs) were "large, swift, and powerfully armed torpedo boats designed to destroy other torpedo boats". Although the term "destroyer" had been used interchangeably with "TBD" and "torpedo boat destroyer" by navies since 1892, the term "torpedo boat destroyer" had been generally shortened to simply "destroyer" by nearly all navies by the First World War.Before World War II destroyers were light vessels with little endurance for unattended ocean operations; typically a number of destroyers and a single destroyer tender operated together. After the war, the advent of the guided missile allowed destroyers to take on the surface combatant roles previously filled by battleships and cruisers. This resulted in larger and more powerful guided missile destroyers more capable of independent operation.

At the start of the 21st century, destroyers are the global standard for surface combatant ships, with only two nations (United States and Russia) operating the heavier class cruisers, with no battleships or true battlecruisers remaining. Modern guided missile destroyers are equivalent in tonnage but vastly superior in firepower to cruisers of the World War II era, and are capable of carrying nuclear tipped cruise missiles. At 510 feet (160 m) long, a displacement of 9,200 tons, and with armament of more than 90 missiles, guided missile destroyers such as the Arleigh Burke-class are actually larger and more heavily armed than most previous ships classified as guided missile cruisers.

Some European navies, such as the French, Spanish, or German, use the term "frigate" for their destroyers, which leads to some confusion.

German submarine U-853

German submarine U-853 was a Type IXC/40 U-boat of Nazi Germany's Kriegsmarine during World War II. Her keel was laid down on 21 August 1942 by DeSchiMAG AG Weser of Bremen. She was commissioned on 25 June 1943 with Kapitänleutnant Helmut Sommer in command. U-853 saw action during the Battle of the Atlantic in World War II. She conducted three patrols, sinking two ships totalling 5,783 tons.

On her final patrol, U-853 was sent to harass United States coastal shipping. She destroyed USS Eagle Boat 56 near Portland, Maine. Just days before Germany's surrender, U-853 torpedoed and sank the collier Black Point during the Battle of Point Judith. American warships quickly found U-853 and sank her 7 nmi (13 km; 8.1 mi) east of Block Island, Rhode Island, resulting in the loss of her entire crew.

U-853 is a popular deep sea diving site. She rests in 121 feet (37 m) of water. Holes in the hull permitted access to the interior of the submarine, though they were welded shut by the United States Navy after bones were stolen from the wreck.

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