The Offshore Patrol (OSP) also known as the Mosquito Fleet was a small naval branch of the United States Army, intended for inshore defense of the Commonwealth of the Philippines. It was active from February 9, 1939 to June 30, 1946. The OSP became part of the United States Army Forces in the Far East (USAFFE) on July 26, 1941, with General Douglas MacArthur as Commander. During the Japanese invasion of the Philippines, the Patrol engaged in limited naval operations along the coastlines of Bataan and Corregidor, against the tight enemy blockade, to bring much-needed provisions to the beleaguered Filipino and American troops during the battle. Undaunted by enemy superiority, the ubiquitous patrol boats fought with zeal, courage and heroism, hitting Japanese warships with torpedoes when given the opportunity. The unit relied on speed and surprise to attack larger vessels at close range.
The United States Asiatic Fleet was a fleet of the United States Navy during much of the first half of the 20th century. Before World War II, the fleet patrolled the Philippine Islands. Much of the fleet was destroyed by the Japanese by February 1942, after which it was dissolved, and the remnants incorporated into the naval component of the South West Pacific Area command, which eventually became the Seventh Fleet.
A river gunboat is a type of gunboat adapted for river operations. River gunboats required shallow draft for river navigation. They would be armed with relatively small caliber cannons, or a mix of cannons and machine guns. If they carried more than one cannon, one might be a howitzer, for shore bombardment. They were usually not armoured. The fictional USS San Pablo described in Richard McKenna's The Sand Pebbles is an example of this class of vessel, serving on the US Navy's Yangtze Patrol. Stronger river warships with larger guns were river monitors.
Motor Torpedo Boat Squadron Three was a United States Navy squadron based at Cavite, Philippines, from September 1941 to mid-April 1942. It was commanded by Lieutenant John D. Bulkeley and made up of six motor torpedo boats: PT-31, PT-32, PT-33, PT-34, PT-35, and PT-41, the last as the squadron flagship. The other six boats of the squadron remained at Pearl Harbor, Hawaii, and were there when war broke out, eventually being shipped to the Solomons.
The Yangtze Patrol, also known as the Yangtze River Patrol Force, Yangtze River Patrol, YangPat and ComYangPat, was a prolonged naval operation from 1854–1949 to protect American interests in the Yangtze River's treaty ports. The Yangtze Patrol also patrolled the coastal waters of China where they protected U.S. citizens, their property, and Christian missionaries.
USS Napa (AT-32), originally Yucca, was a Bagaduce-class fleet tug of the United States Navy. The ship was laid down as Napa on 5 March 1919, at the Puget Sound Naval Shipyard, Washington; launched on 24 July 1919; and commissioned on 5 December 1919.
USS Tanager (AM-5) was an Lapwing-class minesweeper acquired by the U.S. Navy for the dangerous task of removing mines from minefields laid in the water to prevent ships from passing.
The first USS Pigeon (AM-47/ASR-6) was a Lapwing-class minesweeper of the United States Navy. She was later converted to a submarine rescue ship. She was named for the avian ambassador, the pigeon.
USS Tulsa (PG-22), nicknamed the Galloping Ghost of the South China Coast, was an Asheville-class gunboat of the United States Navy that was in commission from 1923 to 1946. She was named after the city of Tulsa, Oklahoma, and the county seat of Tulsa County.
USS Whippoorwill (AM-35) was a Lapwing-class minesweeper of the United States Navy.
The first USS Luzon (PG-47) was laid down 20 November 1926 by the Kiangnan Dock and Engineering Works, Shanghai, China; launched 12 September 1927; sponsored by Miss Mary C. Carter, daughter of Commander Andrew F. Carter, USN; and commissioned 1 June 1928.
The first USS Mindanao (PR‑8) was a river gunboat in the service of the United States Navy before and during World War II.
Trabajador was a 111 foot (33.8 m) tug launched in 1931 by Hong Kong & Whampoa Dock Co., Ltd. for Visayan Stevedore-Transportation Company and registered as a United States vessel in Iloilo, Philippines.
Maryann, sometimes seen as Maryanne or Mary Anne, was a yacht requisitioned and converted by the United States Navy during the defense of the Philippines in World War II and destroyed 5 May 1942 at Corregidor to prevent capture. The yacht was "in service" and not commissioned.
Fisheries II was a vessel requisitioned by the United States Navy during the defense of the Philippines during World War II. The vessel was "in service" and not commissioned.
Q-111 Luzon was a motor torpedo boat of the United States Army during World War II as part of the Offshore Patrol based at Manila.
Q-112 Abra was a motor torpedo boat of the United States Army during World War II as part of the Offshore Patrol based at Manila.
YP-97 was a converted fishing vessel which served as an auxiliary patrol boat in the U.S. Navy during World War II.
Naval Base Manila, Naval Air Base Manila was a major United States Navy base south of the City of Manila, on Luzon Island in the Philippines. Some of the bases dates back to 1898, the end of the Spanish–American War. Starting in 1938 civilian contractors were used to build new facilities in Manila to prepare for World War II. Work stopped on December 23, 1941, when Manila was declared not defendable against the Empire of Japan southward advance, which took over the city on January 2, 1942, after the US declared it an open city. US Navy construction and repair started in March 1945 with the taking of Manila in the costly Battle of Manila ending on March 2, 1945. Naval Base Manila supported the Pacific War and remained a major US Naval Advance Base until its closure in 1971.
US Naval Base Philippines was number of United States Navy bases in the Philippines Islands in the Pacific Ocean. Most were built by the US Navy Seabees, Naval Construction Battalions, during World War II. The US Naval Bases in Philippines were lost to the Empire of Japan in December 1941 during the Philippines campaign of 1941–1942. In February 1945 the United States Armed Forces retook the Philippines in the Battle of Manila in 1945. Before the captured US bases on Luzon were retaken the US Navy Seabees built a new large base, Leyte-Samar Naval Base, on the Philippine Island of Leyte, starting in October 1944.
United States of America 
Commonwealth of the Philippines