TheDigger
10-01-2008, 09:33
General Information
A PT boat was a motor torpedo boat (hull classification symbol "PT", for "Patrol Torpedo"), a small, fast vessel used by the United States Navy in World War II to attack larger surface ships. The PT boat squadrons were nicknamed "the mosquito fleet".
Torpedo boats were first developed in the early 20th century as an inexpensive way to deliver torpedoes which could destroy ships as heavy as battleships without the massive weight necessary for large caliber guns. By WWII, the initial mission of the American PT boats was to battle destroyers, which themselves were a shortened name for "torpedo boat destroyers".
Though many would question the military effectiveness of the boats in this role, their psychological impact in deterring Japanese attacks was significant.
The Navy was short on larger ships as they were just starting the manufacturing of a massive naval fleet which would come later in the war, and wood construction made strategic materials such as steel available for other uses. Later in the war, the boats were much more effective as gunboats against targets their own size, such as armored barges that the Japanese used to shuttle troops and supplies between islands.
PT Class history
The US Navy requested a competitive bid for several different concepts of torpedo boats. This competition led to eight prototype boats built to compete in the 2 different classes. The first class was to be for 55 foot boats, and the second class to be for 70 foot boats.
The resulting PT boat designs were the product of a small cadre of respected naval architects and the Navy. Henry R Sutphen of Electric Launch Company ("Elco") and his Elco designers Irwin Chase, Bill Fleming and Glenville Tremaine, visited the United Kingdom to see their Motor Torpedo Boat designs. While visiting the British Power Boat Company they purchased a 70-foot design (PV70) (later renamed PT-9 during the competition), designed by Hubert Scott-Paine. Other entries in the competition were 2 boats (PT-7 and PT-8) built by Andrew Jackson Higgins of Higgins Industries of New Orleans, and designers at the Huckins Yacht Company also came up with competing 70 foot boat class designs. The US Navy at the Philadelphia Navy Yard, came up with other designs (PT-1 to PT-6). The results of the competition found that none of the boats, as built, were up to the necessary performance specifications identified by the US Navy.
Representatives of Elco had substantial small boat building experience, having built during WW I 550 eighty-foot sub chasers for the British Admiralty. Additionally in 1921, they introduced the famous 26-foot "Cruisette", (a gasoline cabin cruiser). This success in small boat building was followed in the 1930s with 30 ft to 57 ft "Veedettes" and "Flattops", gasoline powered boats that set the highest standard in a golden era of boating. This small boat experience helped Elco obtain a contract for 10 boats based on the 70 foot Scott-Paine Model PT Boat. These 70 foot boats were tested and determined to be too light for open sea work but Elco got a contract for 24 larger boats based on a lengthened 77 foot design.
The design competition and seaworthiness trials for the PT boat was nicknamed "The Plywood Derby" and took place prior to the United States entering the war, in early 1941. The Navy Department held these competition trials around New York Harbor. This was a shakedown to see which company would be contracted to build the Navy PT boats. At the completion of the trials the Navy was impressed with all three designs, with the Elco 77 footer coming out on top, followed by the Higgins 76 footer and Huckins 72 foot boat.
Although Elco came in first, the Navy saw the merits of the other two boats and decided to offer all three companies contracts. Elco received the lion's share of the contract (385 boats by the end of the war), Higgins was second (199 boats by the end of the war) and Huckins with the smallest contract (18 boats by the end of the war, none of which would see combat, being assigned to home defense squadrons in the Panama Canal Zone, Miami, Florida and in Hawaii at Pearl Harbor).
Huckins was a tiny yacht-building company in Jacksonville, Florida and was unable to build the number of boats needed by the Navy. Although they built a few 78-foot (24 m) boats of the PT-95 class, the 80-foot (24.4 m) Elco boats, and the 78-foot (24 m) Higgins boats became the standard American motor torpedo boats of World War II. Even though more 80-foot Elco boats were built than any other type of motor torpedo boat (326 of their 80-foot boats were built) Elco also produced 49 of their 77-foot boats and ten 70-foot boats.
Elco PT Boats
The Elco Naval Division boats were the largest in size of the three types of PT boats built for US Navy used during World War II. The 80 foot (24.4 m) long wooden-hulled were classified as boats in comparison with much larger steel-hulled destroyers, but were comparable in size to many wooden sailing ships in history. They had a 20 ft 8 in (6.3 m) beam. Though often said to be made of plywood, they were actually made of two-inch thick planks of mahogany.
They were powered by three 12-cylinder gasoline fueled engines. These were Packard built, a modified design of the 3A-2500 V-12 liquid-cooled aircraft engine. The 3A was an improved version of the 2A engine used on the Huff-Daland Keystone LB-1 Liberty bomber of World War One vintage. Packard modified them for marine use in PTs, hence the "M" designation instead of "A". (ie 3A-2500 then 4M-2500). Their aircraft roots gave them many features of aircraft engines such as supercharger, intercooler, dual magnetos, two spark plugs per cylinder, and so on. Packard built the Rolls Royce Merlin aero engine under license alongside the 4M-2500, but with the exception of the PT-9 prototype boat brought from England for Elco to examine and copy, the Merlin was never used in PTs.
The 4M-2500s initially generated 1200 hp (895 kW) each, together roughly the same power as a Boeing B-17 bomber. They were subsequently upgraded in stages to 1500 hp (1,150 kW) each for a designed speed of 41 knots (76 km/h). Increases in the weight of the boats during the war meant that the top speed did not go up as the engine power increased. Fuel consumption of these engines was phenomenal - a PT carried 3000 gallons (11,360 liters) of 100 octane avgas.
A normal patrol for these boats would last a maximum of 12 hours. The consumption rate for each engine at a cruising speed of 23 knots was about 66 gallons (250 l) per hour (200 gallons (760 l) per hour for all 3 engines). However, when going at top speed the gasoline consumption increased to 166 gallons (628 l) per hour per engine (or 500 gallons [1,890 l] per hour for all 3 engines). At the top speed of 41+ knots, the 3,000 gallons (11,360 l) of gas would be used in only about 6 hours.
With accommodations for 3 officers and 14 men, the crew varied from 12 to 14, though the PT-59 took on forty to fifty marines from a foundering landing craft. Full-load displacement late in the war was 56 tons.
Early Elco boats had one 20 mm Oerlikon cannon mounted at the stern, and two twin M2 .50 inch (12.7 mm) or .30 inch (7.6 mm) Lewis machine guns mounted in open rotating turrets designed by the same company that would make the Tucker automobile. The primary anti-ship armament was two or four 21 inch (533 mm) torpedo tubes launching Mark 8 torpedoes which weighed about one ton each. Some carried two to four US Navy Mark 6 depth charges in roll off stern racks, or mine racks.
Later boats mounted one 40 mm Bofors gun aft and four 22.5 inch diameter Mark 13 torpedo launching racks, two along each side. Some PTs later received two eight-cell five inch (127 mm) spin stabilized flat trajectory rocket launchers, giving them 16 rockets and as much firepower for a short time as a destroyer mounting five inch guns. By war's end the PT boat had more firepower-per-ton than any other vessel in the U.S. Navy.
One other addition US Navy PTs had was Raytheon SO type radar, with about a 25 nm range. Since PTs operated mainly at night, having radar gave them an advantage over the enemy in being able to locate and engage them even in zero visibility. Although radar is not specifically a weapon, its use by the PT boats made the other weapons much more effective.
In addition, many boats received ad hoc outfits at advanced bases, mounting such weapons as 37 mm aircraft cannon and even captured Japanese 23 mm guns. One famous example was Kennedy's PT-109 which was equipped with a 37 mm single shot anti-tank gun her crew had commandeered and bolted to the fore deck. Another similar type of weapon that gained widespread use as the war progressed was the 37 mm Oldsmobile M4 and M9 aircraft automatic cannon.
Originally cannibalized from crashed P-39 Airacobra fighter planes on Guadalcanal, and then later manufactured and installed at the boat's Elco and Higgins factories, the M4/M9 cannon had a relatively high rate of fire (125 rounds per minute) and large magazine (30 rounds), making it highly desirable due to the PT boat's ever increasing need for a larger "punch" to deal effectively with the Japanese daihatsu barges, which were immune to torpedoes due to their shallow draft. By the war's end, most PTs had these weapons.
Higgins PT Boats
Higgins produced 199 78-foot boats. The Higgins boats, built by Higgins Industries in New Orleans, Louisiana, were 78-foot (24 m) boats of the PT-71 class. The Higgins boats had the same beam, full load displacement, engine, generators, shaft power, trial speed, armament, and crew accommodations as the 80-foot (24 m) Elco boats. Numerous Higgins boats were sent to the USSR and Great Britain at the beginning of the war, so many of the lower squadrons in the USN were made up exclusively of Elcos.
The first Higgins boats for the US Navy were used in the Battle for the Aleutian Islands (Attu and Kiska) as part of Squadron 13, and others in the Mediterranean against the Germans. They were also used in great numbers during the D-Day landings. Gen. Eisenhower once said that that the Higgins boats won the war for the U.S.
A somewhat odd footnote is that even though only half as many Higgins boats were produced, far more survive (six hulls, 2 of which have been restored to their WW2 configuration), than do the more numerously built Elco boats of which only two hulls (one restored) are known to exist at this time.
Additional to the PT Boats Higgins were the main supplier of the Landing Craft used through out the Pacific and During the Normandy D Landings and was by far their most produced craft.
Service
The deck houses of PT boats were protected against small arms fire and splinter. Direct hits from Japanese guns could and did result in catastrophic explosions with near-total crew loss. PTs would attack under the cover of night. They feared attack by Japanese seaplanes, which were hard to detect even with radar, but which could spot the phosphorescent wake left by PT propellers from the air.
Bombing attacks killed and wounded crews even with near misses. Initially, only a few boats were issued primitive radar sets. In some early battles, they were the first to leave after expending their weapons, leaving the remaining boats without radar. The boats would have to sneak close to torpedo range, but once their position was given away by the torpedo launch, they would have to lay down a cloud of smoke from stern-mounted smoke generators to escape from searchlights, or seaplane-dropped flares which illuminated their locations for large caliber gunfire, which PTs lacked.
Depth charges were sometimes used as a last ditch confusion weapon to scare off pursuing destroyers. Gunboat versions mounted extra armor, though tests showed this was not very effective. A small life raft was normally mounted on the forward deck, though it was occasionally displaced by guns.
PT boats lacked the refrigerators with meat, milk, butter and eggs of larger ships. PT crewmen were cross-trained to do many tasks, and they depended on the ingenuity of their cook, who might also be quartermaster and signalman, and what he could do with Spam, Vienna sausage, and beans. Crews would trade with other ships for supplies, or sometimes even fish by aiming rifles or tossing grenades into schools of fish.
Originally conceived as anti-ship weapons, PT boats were publicly credited with sinking several Japanese warships during the period between December 1941 and the fall of the Philippines in March 1942. Attacking at night, PT crews may have sometimes failed to note a possible torpedo failure. Although the American Mark 8 torpedo was troublesome and did have problems with porpoising and circular runs, it could and did have success against several of their targets.
The exploder mechanism Mark 4, installed inside the Mark 8 torpedo was not subject to the same problems as the US submariners were having with their Mark 6 exploders inside of thier Mark 14 torpedoes. After the war, American military interviews with captured veterans of the Imperial Japanese Navy as well as Japanese war record reviews from the time (incomplete records existed, at best) was unable to verify that all the PT boat sinking claims were valid. This, however was not necessarily a cause to invalidate the claims, due to the incomplete nature of the Japanese records, (and maybe a sense of pride with the Japanese Navy refusing to admit what really happened or covering it up due to political circumstances etc.)
There are several recorded instances of PT boats trading fire with friendly aircraft, a situation also familiar to U.S. submariners. Several PT boats were lost due to "freindly fire" from both allied aircraft and destroyers. Overall, the effectiveness of PT boats in the Solomon Islands campaign, where there were numerous engagements between PTs and capital ships, was substantially undermined by defective torpedoes.
The Japanese were initially cautious when operating their capital ships in areas known to have PT boats, since they knew how dangerous their own Type 93s were, and assumed the Americans had equally lethal weapons. In several engagements, the mere presence of PTs was sufficient to disrupt heavily escorted Japanese resupply activities at Guadalcanal, but this tactical advantage did not last long. Nevertheless, the PT Boats mission in the Solomon Islands was deemed a success.
PT boats fought in the long Solomon Islands campaign, which was the first allied ground offensive of island hopping towards Japan. They operated at night and at times of low visibility against Japanese shipborne resupply efforts dubbed by Admiral William Halsey as "The Tokyo Express" in "the Slot", a narrow seaward channel linking the Japanese stronghold at Bougainville to Guadalcanal.
Throughout World War II, PTs operated in the southern, western, and northern Pacific, as well as in the Mediterranean Sea and the English Channel. Some served during the Battle of Normandy. During the D-Day invasion, PTs patrolled the "Mason Line", forming a barrier against the German S-boats attacking the Allied landing forces. They also performed lifesaving and anti-shipping mine destruction missions during the invasion.
Perhaps the most effective use of PTs was as "Barge Busters". Since both the Japanese in the New Guinea area and the Germans in the Mediterranean had lost numerous resupply vessels to Allied airpower during daylight hours, each attempted to resupply their troop concentrations by using shallow draft barges at night in very shallow waters. The shallow depth meant Allied destroyers were unable to follow them due to the risk of running aground and the barges could be protected by an umbrella of shore batteries.
PTs had sufficiently shallow draft to follow them inshore and sink them. Using torpedoes was ineffective against these sometimes heavily armed barges, since the minimum depth setting of the torpedo was about ten feet (3m) and the barges only drew five (1.5m). To accomplish the task, PTs (and RN and RCN MTBs in the Med) installed more and heavier guns which were able to sink the barges. One captured Japanese soldier's diary described their fear of PT boats by describing them as "the monster that roars, flaps it wings, and shoots torpedoes in all directions".
Though their primary mission continued to be seen as attack of surface ships and craft, PT boats were also used effectively to lay mines and smoke screens, to rescue downed aviators, and to carry out intelligence or raider operations.
In 1943 in the Solomon Islands, three 77-foot (23 m) PT boats, PT-59, PT-60, and PT-61, were even converted into gunboats by stripping the boat of all original armament except for the two twin .50 inch (12.7 mm) gun mounts, and then adding two 40 mms and four twin .50 inch (12.7 mm) mounts. Lt. John F. Kennedy was the first commanding officer of PT-59 after the conversion, and participated in evacuating many Marines from Choiseul.
The most famous incident in this campaign was when Lt. Kennedy's PT-109 was sent into Blackett Strait to intercept the Tokyo Express. In what National Geographic called a "poorly planned and badly coordinated" attack, 15 boats with 60 torpedoes attacked, but not a single hit was scored. Patrolling after the action, PT-109 was run down on a dark moonless night by the Japanese destroyer Amagiri, returning from the supply mission; she never even noticed PT-109.
The boat had her engines at idle to hide her wake from seaplanes, and so could not complete a torpedo shot. The survivors were remarkably found by two Solomon Islanders, dispatched in a traditional dugout canoe by an Australian coastwatcher. Only a few days later, a force composed mostly of destroyers would be successful in putting an end to the Japanese supply convoys.
Though his boat was sunk, Kennedy would be awarded a medal, and the incident would become a folk legend in the form of magazine articles, models, toys, hardback and comic books, a hit record, a major motion picture; it also inspired several television shows, starting with McHale's Navy. The wreck was found in 2002 by Robert Ballard who had also found the wreck of the Titanic.
A PT boat was a motor torpedo boat (hull classification symbol "PT", for "Patrol Torpedo"), a small, fast vessel used by the United States Navy in World War II to attack larger surface ships. The PT boat squadrons were nicknamed "the mosquito fleet".
Torpedo boats were first developed in the early 20th century as an inexpensive way to deliver torpedoes which could destroy ships as heavy as battleships without the massive weight necessary for large caliber guns. By WWII, the initial mission of the American PT boats was to battle destroyers, which themselves were a shortened name for "torpedo boat destroyers".
Though many would question the military effectiveness of the boats in this role, their psychological impact in deterring Japanese attacks was significant.
The Navy was short on larger ships as they were just starting the manufacturing of a massive naval fleet which would come later in the war, and wood construction made strategic materials such as steel available for other uses. Later in the war, the boats were much more effective as gunboats against targets their own size, such as armored barges that the Japanese used to shuttle troops and supplies between islands.
PT Class history
The US Navy requested a competitive bid for several different concepts of torpedo boats. This competition led to eight prototype boats built to compete in the 2 different classes. The first class was to be for 55 foot boats, and the second class to be for 70 foot boats.
The resulting PT boat designs were the product of a small cadre of respected naval architects and the Navy. Henry R Sutphen of Electric Launch Company ("Elco") and his Elco designers Irwin Chase, Bill Fleming and Glenville Tremaine, visited the United Kingdom to see their Motor Torpedo Boat designs. While visiting the British Power Boat Company they purchased a 70-foot design (PV70) (later renamed PT-9 during the competition), designed by Hubert Scott-Paine. Other entries in the competition were 2 boats (PT-7 and PT-8) built by Andrew Jackson Higgins of Higgins Industries of New Orleans, and designers at the Huckins Yacht Company also came up with competing 70 foot boat class designs. The US Navy at the Philadelphia Navy Yard, came up with other designs (PT-1 to PT-6). The results of the competition found that none of the boats, as built, were up to the necessary performance specifications identified by the US Navy.
Representatives of Elco had substantial small boat building experience, having built during WW I 550 eighty-foot sub chasers for the British Admiralty. Additionally in 1921, they introduced the famous 26-foot "Cruisette", (a gasoline cabin cruiser). This success in small boat building was followed in the 1930s with 30 ft to 57 ft "Veedettes" and "Flattops", gasoline powered boats that set the highest standard in a golden era of boating. This small boat experience helped Elco obtain a contract for 10 boats based on the 70 foot Scott-Paine Model PT Boat. These 70 foot boats were tested and determined to be too light for open sea work but Elco got a contract for 24 larger boats based on a lengthened 77 foot design.
The design competition and seaworthiness trials for the PT boat was nicknamed "The Plywood Derby" and took place prior to the United States entering the war, in early 1941. The Navy Department held these competition trials around New York Harbor. This was a shakedown to see which company would be contracted to build the Navy PT boats. At the completion of the trials the Navy was impressed with all three designs, with the Elco 77 footer coming out on top, followed by the Higgins 76 footer and Huckins 72 foot boat.
Although Elco came in first, the Navy saw the merits of the other two boats and decided to offer all three companies contracts. Elco received the lion's share of the contract (385 boats by the end of the war), Higgins was second (199 boats by the end of the war) and Huckins with the smallest contract (18 boats by the end of the war, none of which would see combat, being assigned to home defense squadrons in the Panama Canal Zone, Miami, Florida and in Hawaii at Pearl Harbor).
Huckins was a tiny yacht-building company in Jacksonville, Florida and was unable to build the number of boats needed by the Navy. Although they built a few 78-foot (24 m) boats of the PT-95 class, the 80-foot (24.4 m) Elco boats, and the 78-foot (24 m) Higgins boats became the standard American motor torpedo boats of World War II. Even though more 80-foot Elco boats were built than any other type of motor torpedo boat (326 of their 80-foot boats were built) Elco also produced 49 of their 77-foot boats and ten 70-foot boats.
Elco PT Boats
The Elco Naval Division boats were the largest in size of the three types of PT boats built for US Navy used during World War II. The 80 foot (24.4 m) long wooden-hulled were classified as boats in comparison with much larger steel-hulled destroyers, but were comparable in size to many wooden sailing ships in history. They had a 20 ft 8 in (6.3 m) beam. Though often said to be made of plywood, they were actually made of two-inch thick planks of mahogany.
They were powered by three 12-cylinder gasoline fueled engines. These were Packard built, a modified design of the 3A-2500 V-12 liquid-cooled aircraft engine. The 3A was an improved version of the 2A engine used on the Huff-Daland Keystone LB-1 Liberty bomber of World War One vintage. Packard modified them for marine use in PTs, hence the "M" designation instead of "A". (ie 3A-2500 then 4M-2500). Their aircraft roots gave them many features of aircraft engines such as supercharger, intercooler, dual magnetos, two spark plugs per cylinder, and so on. Packard built the Rolls Royce Merlin aero engine under license alongside the 4M-2500, but with the exception of the PT-9 prototype boat brought from England for Elco to examine and copy, the Merlin was never used in PTs.
The 4M-2500s initially generated 1200 hp (895 kW) each, together roughly the same power as a Boeing B-17 bomber. They were subsequently upgraded in stages to 1500 hp (1,150 kW) each for a designed speed of 41 knots (76 km/h). Increases in the weight of the boats during the war meant that the top speed did not go up as the engine power increased. Fuel consumption of these engines was phenomenal - a PT carried 3000 gallons (11,360 liters) of 100 octane avgas.
A normal patrol for these boats would last a maximum of 12 hours. The consumption rate for each engine at a cruising speed of 23 knots was about 66 gallons (250 l) per hour (200 gallons (760 l) per hour for all 3 engines). However, when going at top speed the gasoline consumption increased to 166 gallons (628 l) per hour per engine (or 500 gallons [1,890 l] per hour for all 3 engines). At the top speed of 41+ knots, the 3,000 gallons (11,360 l) of gas would be used in only about 6 hours.
With accommodations for 3 officers and 14 men, the crew varied from 12 to 14, though the PT-59 took on forty to fifty marines from a foundering landing craft. Full-load displacement late in the war was 56 tons.
Early Elco boats had one 20 mm Oerlikon cannon mounted at the stern, and two twin M2 .50 inch (12.7 mm) or .30 inch (7.6 mm) Lewis machine guns mounted in open rotating turrets designed by the same company that would make the Tucker automobile. The primary anti-ship armament was two or four 21 inch (533 mm) torpedo tubes launching Mark 8 torpedoes which weighed about one ton each. Some carried two to four US Navy Mark 6 depth charges in roll off stern racks, or mine racks.
Later boats mounted one 40 mm Bofors gun aft and four 22.5 inch diameter Mark 13 torpedo launching racks, two along each side. Some PTs later received two eight-cell five inch (127 mm) spin stabilized flat trajectory rocket launchers, giving them 16 rockets and as much firepower for a short time as a destroyer mounting five inch guns. By war's end the PT boat had more firepower-per-ton than any other vessel in the U.S. Navy.
One other addition US Navy PTs had was Raytheon SO type radar, with about a 25 nm range. Since PTs operated mainly at night, having radar gave them an advantage over the enemy in being able to locate and engage them even in zero visibility. Although radar is not specifically a weapon, its use by the PT boats made the other weapons much more effective.
In addition, many boats received ad hoc outfits at advanced bases, mounting such weapons as 37 mm aircraft cannon and even captured Japanese 23 mm guns. One famous example was Kennedy's PT-109 which was equipped with a 37 mm single shot anti-tank gun her crew had commandeered and bolted to the fore deck. Another similar type of weapon that gained widespread use as the war progressed was the 37 mm Oldsmobile M4 and M9 aircraft automatic cannon.
Originally cannibalized from crashed P-39 Airacobra fighter planes on Guadalcanal, and then later manufactured and installed at the boat's Elco and Higgins factories, the M4/M9 cannon had a relatively high rate of fire (125 rounds per minute) and large magazine (30 rounds), making it highly desirable due to the PT boat's ever increasing need for a larger "punch" to deal effectively with the Japanese daihatsu barges, which were immune to torpedoes due to their shallow draft. By the war's end, most PTs had these weapons.
Higgins PT Boats
Higgins produced 199 78-foot boats. The Higgins boats, built by Higgins Industries in New Orleans, Louisiana, were 78-foot (24 m) boats of the PT-71 class. The Higgins boats had the same beam, full load displacement, engine, generators, shaft power, trial speed, armament, and crew accommodations as the 80-foot (24 m) Elco boats. Numerous Higgins boats were sent to the USSR and Great Britain at the beginning of the war, so many of the lower squadrons in the USN were made up exclusively of Elcos.
The first Higgins boats for the US Navy were used in the Battle for the Aleutian Islands (Attu and Kiska) as part of Squadron 13, and others in the Mediterranean against the Germans. They were also used in great numbers during the D-Day landings. Gen. Eisenhower once said that that the Higgins boats won the war for the U.S.
A somewhat odd footnote is that even though only half as many Higgins boats were produced, far more survive (six hulls, 2 of which have been restored to their WW2 configuration), than do the more numerously built Elco boats of which only two hulls (one restored) are known to exist at this time.
Additional to the PT Boats Higgins were the main supplier of the Landing Craft used through out the Pacific and During the Normandy D Landings and was by far their most produced craft.
Service
The deck houses of PT boats were protected against small arms fire and splinter. Direct hits from Japanese guns could and did result in catastrophic explosions with near-total crew loss. PTs would attack under the cover of night. They feared attack by Japanese seaplanes, which were hard to detect even with radar, but which could spot the phosphorescent wake left by PT propellers from the air.
Bombing attacks killed and wounded crews even with near misses. Initially, only a few boats were issued primitive radar sets. In some early battles, they were the first to leave after expending their weapons, leaving the remaining boats without radar. The boats would have to sneak close to torpedo range, but once their position was given away by the torpedo launch, they would have to lay down a cloud of smoke from stern-mounted smoke generators to escape from searchlights, or seaplane-dropped flares which illuminated their locations for large caliber gunfire, which PTs lacked.
Depth charges were sometimes used as a last ditch confusion weapon to scare off pursuing destroyers. Gunboat versions mounted extra armor, though tests showed this was not very effective. A small life raft was normally mounted on the forward deck, though it was occasionally displaced by guns.
PT boats lacked the refrigerators with meat, milk, butter and eggs of larger ships. PT crewmen were cross-trained to do many tasks, and they depended on the ingenuity of their cook, who might also be quartermaster and signalman, and what he could do with Spam, Vienna sausage, and beans. Crews would trade with other ships for supplies, or sometimes even fish by aiming rifles or tossing grenades into schools of fish.
Originally conceived as anti-ship weapons, PT boats were publicly credited with sinking several Japanese warships during the period between December 1941 and the fall of the Philippines in March 1942. Attacking at night, PT crews may have sometimes failed to note a possible torpedo failure. Although the American Mark 8 torpedo was troublesome and did have problems with porpoising and circular runs, it could and did have success against several of their targets.
The exploder mechanism Mark 4, installed inside the Mark 8 torpedo was not subject to the same problems as the US submariners were having with their Mark 6 exploders inside of thier Mark 14 torpedoes. After the war, American military interviews with captured veterans of the Imperial Japanese Navy as well as Japanese war record reviews from the time (incomplete records existed, at best) was unable to verify that all the PT boat sinking claims were valid. This, however was not necessarily a cause to invalidate the claims, due to the incomplete nature of the Japanese records, (and maybe a sense of pride with the Japanese Navy refusing to admit what really happened or covering it up due to political circumstances etc.)
There are several recorded instances of PT boats trading fire with friendly aircraft, a situation also familiar to U.S. submariners. Several PT boats were lost due to "freindly fire" from both allied aircraft and destroyers. Overall, the effectiveness of PT boats in the Solomon Islands campaign, where there were numerous engagements between PTs and capital ships, was substantially undermined by defective torpedoes.
The Japanese were initially cautious when operating their capital ships in areas known to have PT boats, since they knew how dangerous their own Type 93s were, and assumed the Americans had equally lethal weapons. In several engagements, the mere presence of PTs was sufficient to disrupt heavily escorted Japanese resupply activities at Guadalcanal, but this tactical advantage did not last long. Nevertheless, the PT Boats mission in the Solomon Islands was deemed a success.
PT boats fought in the long Solomon Islands campaign, which was the first allied ground offensive of island hopping towards Japan. They operated at night and at times of low visibility against Japanese shipborne resupply efforts dubbed by Admiral William Halsey as "The Tokyo Express" in "the Slot", a narrow seaward channel linking the Japanese stronghold at Bougainville to Guadalcanal.
Throughout World War II, PTs operated in the southern, western, and northern Pacific, as well as in the Mediterranean Sea and the English Channel. Some served during the Battle of Normandy. During the D-Day invasion, PTs patrolled the "Mason Line", forming a barrier against the German S-boats attacking the Allied landing forces. They also performed lifesaving and anti-shipping mine destruction missions during the invasion.
Perhaps the most effective use of PTs was as "Barge Busters". Since both the Japanese in the New Guinea area and the Germans in the Mediterranean had lost numerous resupply vessels to Allied airpower during daylight hours, each attempted to resupply their troop concentrations by using shallow draft barges at night in very shallow waters. The shallow depth meant Allied destroyers were unable to follow them due to the risk of running aground and the barges could be protected by an umbrella of shore batteries.
PTs had sufficiently shallow draft to follow them inshore and sink them. Using torpedoes was ineffective against these sometimes heavily armed barges, since the minimum depth setting of the torpedo was about ten feet (3m) and the barges only drew five (1.5m). To accomplish the task, PTs (and RN and RCN MTBs in the Med) installed more and heavier guns which were able to sink the barges. One captured Japanese soldier's diary described their fear of PT boats by describing them as "the monster that roars, flaps it wings, and shoots torpedoes in all directions".
Though their primary mission continued to be seen as attack of surface ships and craft, PT boats were also used effectively to lay mines and smoke screens, to rescue downed aviators, and to carry out intelligence or raider operations.
In 1943 in the Solomon Islands, three 77-foot (23 m) PT boats, PT-59, PT-60, and PT-61, were even converted into gunboats by stripping the boat of all original armament except for the two twin .50 inch (12.7 mm) gun mounts, and then adding two 40 mms and four twin .50 inch (12.7 mm) mounts. Lt. John F. Kennedy was the first commanding officer of PT-59 after the conversion, and participated in evacuating many Marines from Choiseul.
The most famous incident in this campaign was when Lt. Kennedy's PT-109 was sent into Blackett Strait to intercept the Tokyo Express. In what National Geographic called a "poorly planned and badly coordinated" attack, 15 boats with 60 torpedoes attacked, but not a single hit was scored. Patrolling after the action, PT-109 was run down on a dark moonless night by the Japanese destroyer Amagiri, returning from the supply mission; she never even noticed PT-109.
The boat had her engines at idle to hide her wake from seaplanes, and so could not complete a torpedo shot. The survivors were remarkably found by two Solomon Islanders, dispatched in a traditional dugout canoe by an Australian coastwatcher. Only a few days later, a force composed mostly of destroyers would be successful in putting an end to the Japanese supply convoys.
Though his boat was sunk, Kennedy would be awarded a medal, and the incident would become a folk legend in the form of magazine articles, models, toys, hardback and comic books, a hit record, a major motion picture; it also inspired several television shows, starting with McHale's Navy. The wreck was found in 2002 by Robert Ballard who had also found the wreck of the Titanic.