On patrol somewhere off the Philippines late one night in the middle of 1943, a Japanese
destroyer slowly cruises through shallow coastal waters.
Her captain scans the horizon with his binoculars, but the seas are pitch black.
He's not worried about an American submarine attack, the waters are too shallow here, and
besides bristling with weapons as she is, the destroyer is more than capable of defending
herself if attacked either by sea or air.
The big guns of the American battleships also don't worry him, the Americans are still rebuilding
their fleet after the devastation of Pearl Harbor half a year ago.
Even if by some miracle an American battleship was in the vicinity, well, Japanese destroyers
are formidable themselves, and he could always call for air support from a nearby airfield-
it would be a suicidal attack.
Confident in his ship and his men both, the Japanese Captain allows himself to relax for
a moment, he even considers retiring to his quarters and letting his second assume command
for yet another uneventful night.
Then, suddenly, the ship is rocked by an explosion at her bow!
Submarines?
Impossible, the waters are too shallow!
Scanning the seas he doesn't see the silhouette of a large American ship against the moonlit
waters either.
Suddenly a second explosion strikes the destroyer amidships, sending the bridge crew to the
floor.
As they pick themselves up they hear the approaching roars of engines- aircraft?!
Impossible, no chance American airplanes could be so accurate in the dead of night!
Yet the roar of engines grows, and soon there's a third explosion and the ship lists.
Scanning the dark with spotlights, Japanese crewmen catch glimpses of something unbelievable-
small, agile speed boats loaded with torpedo tubes and machine guns are roaring by the
big destroyer, reaching speeds of up to 45 mph (73 km/h)!
The big destroyer turns her guns to defend herself but the small boats are too fast and
agile, and in minutes they've landed several more direct hits.
As the Japanese destroyer sinks, a small fleet of 4 American PT boats roars off into the
night, disappearing as suddenly as they had arrived.
The legendary PT boat of World War II had its origins in the days before World War I,
when military planners saw potential for a small, high-speed ship that could deliver
torpedoes and flee from combat before the enemy could sink it.
Despite several successful trials and some interest from both the Americans and the British,
the designs were scrapped in favor of big gun battleships and cruisers- this was the
age of the Dreadnought after all, and the world firmly believed that naval power lay
in big ships and even bigger guns.
Yet as technology progressed and ever more powerful engines were developed, small speed
boats began setting incredible speed records of up to 60 mph (96 kmh) on calm seas.
Speed derbies featuring ever faster boats had become very popular in America, and in
the late 1930s military engineers began seeing the potential once more for small, agile boats
capable of launching deadly hit and run attacks.
In 1938, with the probability of the US going to war soon, the US Navy sponsored a design
competition for a highly mobile attack boat, reaching out to the designers of speed boats
used in the popular derbies.
The competition led to the construction of eight prototype boats which would compete
in two different classes.
The first class of boat was for 54 foot (16 m) boats, and the second for larger, more
heavily armed 70 foot (21 m) boats.
Prizes for winning designs were awarded on the 30thof March, 1939, and on June 8thof
that year, contracts were awarded to the Fogal Boat Yard of Miami, Florida, and the Fisher
Boat Works of Detroit, Michigan.
This led to the development of the first four official PT Boats to be tested and refined
by the US Navy.
In March of 1941, a squadron of Navy PT boats made a run from Key West to New York.
The 70-footers as they were known were heavily pounded by seas reaching 8 to 10 feet in height,
and the boats were only able to travel at moderate speeds well below their maximum.
The crew suffered from extreme discomfort and fatigue, and the boats each suffered several
structural failures.
The hulls were clearly deficient and the navy ordered immediate overhauls to the basic design.
Later that July, the Navy gathered together nine boats of different designs and held an
open-ocean trial to test each boat- the sailors involved would reference the test as the Plywood
Derby, so named for the light wood from which most of the boats were made.
The open ocean trial would run a course of 220 miles (350km) with each boat at full throttle,
and each ship would carry either live ordinance or copper ingots that would stand-in for actual
weapons.
Of the nine ships that partook, only six finished the trial successfully, with the fastest ship
clocking in at an average speed of 45.71 mph (73.56 kmh).
A second trial later on in August would see the ships running a 213 mile (343 km) course
through much heavier seas, with waves reaching heights of 16 feet (4.9 m).
Six designs took part in the trial and all but one completed successfully.
Even with rough seas, the fastest boat reached an average speed of 31.6 mph (50.9 kmh).
The Bureau of Ships quickly issued a report encouraging the immediate construction of
several PT boat designs, all to be armed with dual torpedo tubes, machine guns, and depth
charges.
Each boat varied in crew size, but typically ran from three officers and 14 enlisted men
up to as many as 17, depending on the total weapons loadout of each ship.
The hulls were made of two sheets of mahogany planking with a glue-impregnated cloth layer
in between the inner and outer planks.
At a time when ships of war featured heavy belts of steel armor that were anywhere from
several inches to a foot or more thick in places, the wood panel construction of a PT
boat must have seemed suicidal.
Yet the lightweight wooden hulls allowed the boats to reach incredible speeds even when
fully loaded with weapons, and a PT boat that had just emptied its torpedo tubes and spent
its depth charges could speed away at speeds up to 60 mph (96 kmh).
Plus the wooden hulls were incredibly easy to repair, and the ships were capable of sustaining
catastrophic damage and surviving.
When future US President John F. Kennedy's PT boat was ran over by a Japanese destroyer
and cut in half, the two halves of the ship managed to remain afloat for a full 12 hours.
PT-323 when cut in half by a kamikaze aircraft on december 10th, 1944 also remained afloat
for hours.
PT-308 collided with another PT boat by accident during a night mission and had her stern completely
sheared off, yet managed to return to base for repairs.
Easy to repair and extremely survivable after receiving battle damage, the wooden hulls
of PT boats also afforded them a great degree of protection form metal-detecting sea mines,
and in some cases even from enemy torpedoes.
On the 5thof November, 1943, a torpedo fired at PT-167 shot straight through the hull of
the boat without detonating, and the boat remained in action until being repaired the
next day.
Nicknamed the 'mosquito fleet' or 'devil boats' by the Japanese, PT boats may have been small
but they packed a formidable punch.
Each boat carried a primary anti-ship armament of anywhere from two to four Mark 8 torpedoes,
packed with 466 pounds (211 kg) of TNT.
The torpedos had a range of 16,000 yards and could zip through the water as fast as a PT
boat itself, reaching speeds of up to 41 mph (67 kmh).
However the explosive charges that fired them from their containers became a dead-giveaway
when conducting nighttime attacks, and thus they were eventually replaced in 1943 by lighter,
more powerful Mark 13 torpedos featuring a 600 pound Torpex-filled warhead.
Torpex was a new explosive which featured 50% greater explosive energy by mass over
traditional TNT, seriously upgrading the firepower of America's PT boats.
The new torpedos were also fired from roll-off launch racks, eliminating the tell-tale explosive
burst that would give PT boats away at night.
Each PT boat was also equipped with at least two twin .50 cal machine guns which could
be used an anti-aircraft weapons.
On the stern would also be mounted a 20mm Oerlikon cannon which was capable of punching
through light ship armor.
Forward of the chart house would be two .30 caliber Lewis machine guns on pedestal mounts,
as well as one or two .30 caliber Browning machine guns on the forward torpedo racks.
The PT boat literally bristled with armament, yet a year into the war the US decided that
PT boats definitely needed more guns and started installing additional 20mm cannons amidships
and on the forward deck.
Yet for some PT boat captains and enterprising engineers with lots of time on their hands,
even this wasn't enough.
PT boats became famous for the high degree of customized and 'home-built' retrofits,
with engineers at forward bases in the Pacific mounting everything onto PT boats from 37mm
aircraft cannons to rocket launchers and even mortars.
After proving how successful the additional firepower was, the Navy immediately adopted
the modifications into the official design.
Still, custom modification pervaded the PT boat fleet, and one of the most famous was
future US President John F. Kennedy's PT-109, which featured a single-shot Army M3 37mm
anti-tank gun that the crew had commandeered.
The enterprising sailors and mechanics removed the wheels and lashed it to 2x8 timbers before
affixing the cannon to the bow.
The M3 anti-tank gun proved devastatingly effective against ships, despite being made
to take out enemy tanks, but the single-shot action limited its usefulness.
Enterprising PT Boats crew found the answer to their problem by cannibalizing the Oldsmobile
M4 aircraft automatic cannons from crashed P-39 Airacobra fighter planes.
Once more demonstrating the effectiveness of in-the-field ingenious customizations,
the auto cannon was approved as part of the factory design.
Originally conceived as anti-ship weapons, PT boats saw their roles vary dramatically
as the war in the Pacific raged on.
Some boats were converted to gunboats featuring nothing but heavy machine guns which would
aid landing US troops, or in the rescue of downed pilots.
Others would provide close-in fire support with mortars for troops near the beaches,
delivering more accurate fire than the big guns of battleships and destroyers sitting
a half dozen or more miles away.
Yet the primary role of the PT boat was always to harass and interdict Japanese shipping,
and to do their job effectively they would operate primarily at night.
While at first only a few PT boats were fitted with radar, eventually the use of radar spread
across the PT fleet, which dramatically improved the success of nighttime raids on Japanese
ships.
During the Solomon Islands campaign, PT boats waged a deadly campaign against Japan's resupply
efforts, dubbed “The Tokyo Express”.
Operating in groups of 6-8, the boats would lie in wait for Japanese ships, loitering
silently just out of torpedo range.
Once a target appeared, the boats would roar to life and pounce on the unsuspecting enemy
ship, loosing a deadly volley of torpedoes.
Though their primary targets were Japanese shipping barges which proved difficult to
sink by submarines due to their low-draught hull design, the PT boats regularly took on
much more heavily armed opponents, even battleships.
During the campaign Japanese captains were cautious about operating their big capital
ships in any waters known to be prowled by the deadly American speed demons.
Yet the most effective use of PT boats was as “barge busters”.
After losing heavy numbers of resupply barge ships to Allied naval power, both the Germans
in the Mediterranean and the Japanese in the Pacific began operating their barges at night
in very shallow waters.
This would make it impossible for Allied destroyers to follow them due to the risk of running
aground, and allowed the barges to be protected by shore-based firepower.
Yet the shallow waters were no problem for the American PT boats, which would zip in
at daredevil speeds and deliver deadly torpedoes while strafing the barges with cannon and
machine gun fire.
By the time shore-based firepower could respond, the Americans would be long gone, leaving
nothing but a sinking wreck in their wake.
The use of PT boats in the Pacific was directly credited as the reason why Japanese soldiers
suffered severe food, ammunition, and personnel resupply problems.
One captured Japanese soldier's diary described his fear of American PT boats, describing
them as “the monster that roars, flaps its wings, and shoots torpedoes in all directions”.
America's first great naval commander, John Paul Jones, once said, “I wish to have no
connection with any ship that does not sail fast; for I intend to go in harm's way.”,
and we are sure that he would have been mightily pleased with the legendary speed demons of
World War II.
Fast, agile, and packing a deadly punch, PT boats were the knife-fighters of the Pacific,
darting into extremely close ranges to deliver crippling blows against enemy ships that ranged
from supply barges up to destroyers and battleships.
These were extraordinary weapons, manned by extraordinary men who knew the only thing
standing between them and death was one thing: speed.
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