In 1935, the Commonwealth Government passed the National Defense Act, which aimed to ensure the security of the country.
This was criticized because it placed the burden of the defense of the Philippines on ground forces, which in turn, was formed from reservists.
It discounted the need for a Commonwealth air force and navy, and naval protection was provided by the United States Asiatic Fleet.

"A relatively small fleet of such vessels, ...will have distinct effect in compelling any hostile force to approach cautiously and by small detachments."

— Gen. Douglas MacArthur, Military Advisor to the Philippines regarding the newest Offshore Patrol (OSP) PT boats
When World War II began, the Philippines had no significant naval forces after the United States withdrew the Asiatic Fleet following the attack on Pearl Harbor by the Imperial Japanese Navy.
The Philippines had to rely on its OSP with headquarters located at Muelle Del Codo, Port Area, Manila, composed of five high-speed Thorneycroft Coast Motor Boat (CMB) 55-foot (17 m) and 65-foot (20 m) PT boats, also known as Q-boats, to repel Japanese attacks from the sea.

During the course of the war, the OSP were undaunted by the enemy's superiority which they fought with zeal, courage and heroism.
For its intrepid and successful missions and raids on enemy ships, the unit was dubbed the "Mosquito Fleet" mainly because of its minuscule size, speed and surprise, it showed its capability to attack with a deadly sting.
The unit was cited for gallantry in action when its Q-boats Squadron shot three of nine Japanese dive bombers as they were flying towards shore installations in Bataan.
The OSP participated in the evacuation of high Philippine and U.S. government officials from Manila to Corregidor when Manila was declared an open city.

Surviving personnel of the Offshore Patrol that didn't surrender after April 9, 1942 to the Japanese, conducted the recognized guerrilla and local military troops of the Philippine Commonwealth Army were hit-and-run attacks against the occupying Japanese forces until the return of U.S. Forces.
By the end of the war, 66 percent of its men were awarded the Silver Star Medal and other decorations for gallantry in action.
In 1935, the Commonwealth Government passed the National Defense Act, which aimed to ensure the security of the country. This was criticized because it placed the burden of the defense of the Philippines on ground forces, which in turn, was formed from reservists. It discounted the need for a Commonwealth air force and navy, and naval protection was provided by the United States Asiatic Fleet.
"A relatively small fleet of such vessels, ...will have distinct effect in compelling any hostile force to approach cautiously and by small detachments."
— Gen. Douglas MacArthur, Military Advisor to the Philippines regarding the newest Offshore Patrol (OSP) PT boats
When World War II began, the Philippines had no significant naval forces after the United States withdrew the Asiatic Fleet following the attack on Pearl Harbor by the Imperial Japanese Navy. The Philippines had to rely on its OSP with headquarters located at Muelle Del Codo, Port Area, Manila, composed of five high-speed Thorneycroft Coast Motor Boat (CMB) 55-foot (17 m) and 65-foot (20 m) PT boats, also known as Q-boats, to repel Japanese attacks from the sea.
During the course of the war, the OSP were undaunted by the enemy's superiority which they fought with zeal, courage and heroism. For its intrepid and successful missions and raids on enemy ships, the unit was dubbed the "Mosquito Fleet" mainly because of its minuscule size, speed and surprise, it showed its capability to attack with a deadly sting. The unit was cited for gallantry in action when its Q-boats Squadron shot three of nine Japanese dive bombers as they were flying towards shore installations in Bataan. The OSP participated in the evacuation of high Philippine and U.S. government officials from Manila to Corregidor when Manila was declared an open city.
Surviving personnel of the Offshore Patrol that didn't surrender after April 9, 1942 to the Japanese, conducted the recognized guerrilla and local military troops of the Philippine Commonwealth Army were hit-and-run attacks against the occupying Japanese forces until the return of U.S. Forces. By the end of the war, 66 percent of its men were awarded the Silver Star Medal and other decorations for gallantry in action.
Philippine Navy