SHIPS-IN-CLASS (326): PT 103-196; PT 314-367; PT 372-383; PT 486-563; PT 565-622; PT 623-624 (both cancelled); PT 731-760; PT 761-790 (all cancelled)
OPERATORS: United Kingdom; United States
PROPULSION: 3 x Packard 3M-2500 / 4M-2500 / 5M-2500 12-cylinder gasoline-fueled engines developing 1,200 to 1,850 horsepower each to 3 x shafts.
Detailing the development and operational history of the ELCO PT Boat (Patrol Torpedo) Patrol Boat / Motor Torpedo Boat.
Entry last updated on 8/2/2016.
Authored by Dan Alex. Content ©www.MilitaryFactory.com.
Prior to (and during) World War 2, the United States Navy (USN) contracted out to three primary manufacturers for the construction of "PT" motor boats (PT = "Patrol Torpedo"). These surface vessels were built on speed and intended to mount enough sufficient firepower to tackle surface ships of equal or larger classes. The three firms in question became Higgins Industries, Huckins Yacht Corporation and Electric Launch Company (popularly shortened to "ELCO") of which four major classes of PT boats ultimately emerged known as PT-20, PT-71, PT-95 and PT-103 - each differentiated by hull length and manufacturer. ELCO handled the 77-foot PT-20s and - the largest of the American PT boats - the 80-foot PT-103s while Higgins took on the 78-foot PT-71 and Huckins the PT-95. Amazingly, the ELCO firm maintained origins as far back as 1893 and charged during World War 1 with production of small naval vessels for the war effort. However, as the world war came to a close so too did the need for ELCO products.
In the late 1930s, the world was on the verge of war once again as national armies ramped up development and production amidst a Great Depression. Germany and Italy became active within Europe (with a little bloody help from the Spanish Civil War) while the Japanese Empire moved into China. The US military initially developed three designs to fulfill their PT boat need (further divided into a 55-foot and 70-foot class) and a total of eight vessels - numbered "PT-1" through "PT-8" - were ultimately produced. While serviceable naval vessels in their own right, the group lacked the performance and capabilities that the USN sought.
After a visit to Europe, ELCO representatives procured a high speed boat from British Power Boat Company. The boat was based on a Hubert Scott-Paine design and initially designed as a private venture around an advanced speed boat measuring 70 feet from bow to stern. ELCO utilized this design as the basis for its 40-ton PT submission (also known as the "Scott-Paine Boat") and armed the type to USN specifications with 4 x 457mm British-length torpedo launchers. The USN assigned the boat the designation of "PT-9" and formally accepted the type on an experimental basis, ordering 10 examples as PT-10 through PT-19 and requiring use of 3 x Packard marine gasoline engines of 1,200 horsepower each as well as revised crew areas. These vessels entered USN service in November of 1940.
However, the USN was not fully satisfied with these 70-foot PT boats for they lacked the necessary space to mount the 533mm torpedo. Additionally, the 70-foot hull length of the PT-9 class shown itself to suffer in unforgiving open sea environments. As such, the USN came to ELCO once more - this time with a refined set of changes to their 70-foot design - and contracted for 24 new vessels to be designated PT-20 through PT-44. Most important of these revisions was the increasing of the 70-foot the hull length to 77 feet to help compensate for both rough seas handling and the longer USN 533mm torpedo.
By this time, and before American involvement in World War 2, the Board of Inspection and Survey (of the US Navy Department) took to a new competitive trial to take place offshore of New London during a mid-summer's week in July of 1941. In the testing, new boat designs were submitted from ELCO, Higgins and Huckins. While the USN maintained experience in working with ELCO from earlier, Higgins and Huckins both took to designing competing PT boat systems as private ventures. The final group of seven boats (including the ELCO PT-20) entered into the competition measured between 70 and 81 feet in length and were trialed through various exercises including operations out at sea. This event came to be known historically as the "Plywood Derby" and would decide the true winner of the lucrative USN PT boat contract (the "plywood" name despite the fact that the boats were not constructed of plywood at all).
All that said, USN representatives actually found the submissions from the three major manufacturers worthy of further development. When notes were officially tallied, the ELCO design was the frontrunner because of its inherent handling and speed though it suffered in rough seas. The Higgins 76-footer and the Huckens 72-footer were both admirable endeavors in their own right and, as a result, the USN offered all three concerns individual contracts for development and production of their respective PT boat designs. Of the three, however, ELCO would remain the largest producer of PT boats for the American Navy for the duration of the upcoming war. The design was also furthered by the USN request for a longer 80-foot hull by ELCO based on their 77-foot design - this becoming the famous "PT-103" class of torpedo boats used in large numbers throughout the upcoming war.
All USN PT boats were powered by 3 x Packard 2500 series V-12, centrifugal gear-driven, 100 octane gasoline-fueled, water-cooled engines exhausting through six ports at the outboard stern wall. These powerplants were based on an existing - though modified for marine service - aircraft engine, the Packard 3A-2500 (this engine itself originating back to the American "Liberty" bomber engine of 1925). By this time, ELCO had modified the engine to serve in marine vessels and used an "M" to designate the marine powerplants, giving rise to the 3M-2500 series engine. Output power of the series (as a whole) proved excellent for the boat class though, as can be expected, natural drawbacks included noise output and high fuel consumption. If running on a consistently full load, the engines could give only up to 6.3 hours of total endurance. During typical usage, PT boat captains managed on one engine to conserve fuel and also preserve the element of surprise. The Packard engine series was progressively uprated with the arrival of the super-charged, water-cooled 4M-2500 (1,200 to 1,500 horsepower) and the final production 5M-2500 of 1,850 horsepower (3 x 1,850 = 5,550 combined horsepower). While Packard was also commissioned to produce the excellent Merlin aircraft engines that powered the famous Supermarine Spitfire fighters of Britain, these were never actually used in ELCO PT boats - instead reserved for the overseas British aircraft demand.
A standard ELCO PT boat of 1943 displaced between 38 to 51 tons with a running length of 80 feet, a beam of 20.75 feet and a draught of just 5 feet - the latter a true tactical advantage if attacked by enemy torpedoes, which require a certain depth of the target under the waterline. Top speed from the combine engine output (concerning the base 1,350 horsepower engine) was approximately 43 knots in ideal conditions. A typical weapons load came to be 4 x 533mm (21-inch) torpedo tubes with 4 x ready-to-fire torpedoes, 1 x 40mm Bofors cannon and 4 x 0.50 caliber Browning heavy machine guns. A typical crew complement was 11 personnel including two officers. By 1945, the later versions of the vessel weighed in at an increased 61 tons and managed a lower top speed of 41 knots. The crew had increased to 14 persons including two officers. However, these systems fitted much more flexible armament arrangements and radar was eventually in widespread use, these installations easily identifiable by the antenna masts (capped with "drum" type installations) at amidships.
ELCO PT Boat (Patrol Torpedo) (Cont'd)
Patrol Boat / Motor Torpedo Boat
On December 7th, 1941, the Imperial Navy of the Japanese Empire attacked the US fleet at Pearl Harbor, Hawaii, throwing the United States into full scale war. In response, ELCO PT boats based at Hawaii were also dramatically pushed into wartime service. These were still, however, the early-form versions with their 77-foot hulls and their British-length 457mm torpedoes. Regardless, the ELCO 77-foot PT boats became the first of their type to see combat action in the war. Some vessels of RON 1 were set into action during the Japanese Pearl Harbor attack itself and a total of 49 of the type were produced in all with designations PT-20 through PT-68. 39 were used by the USN while a further 10 were delivered to Britain via Lend-Lease in 1942. 77-foot versions were crewed by 10 personnel including two officers, weighed in at 46 tons and managed 42 knots from their 3 x 1,200 horsepower engine installations. In the early phases of the war, reports of sunken Japanese warships were mistakenly attributed to PT boats in action. They would, however, eventually claim their fair share of tonnage by war's end.
Construction of ELCO boat hulls revolved around use of mahogany in a "double-diagonal" planking pattern while glue and canvas were also utilized. This made for a relatively light yet robust hull design that was further held in place by conventional screws and riveting. The wood construction made for relatively quick repairs of battle damaged sections "in-the-field" and allowed the type to absorb great levels of punishment through either regular use or direct combat action. Additionally, it was the unique hull design of PT boats that separated them from other patrol types for the underside bow began as a sharply-formed "Vee" shape and evolved into a largely flat surface by the stern. This approach was not a naval evolution of any sort for it already saw widespread use in yatch vessels of the time. The hull also allowed for a shallow draught allowing PTs to manage waters that other warships could not. Amazingly, ELCO boats survived the length of the war without many major modifications to their original design despite suggestions that fell to naught. A variety of camouflage schemes existed throughout their operational service - from various blacks to blues and greens to greys. Additional paint schemes were also experimented with but never formally accepted into USN service including an outlandish black-and-white horizontally striped example designed to lessen the long range profile to tracking eyes.
As with any surface warship, armament was the true heart of the ELCO PT boat design and varied highly based on wartime need. It was such that the ELCO armament suite blossomed as the war progressed leading to some very impressive outfits for the series. Standardized armament included torpedoes (numbering four, held as inline pairs at outboard port and starboard side launch tubes, angled to fire away from the vessel's centerline), traversing cannon mounts (found at either the bow, amidships or stern), general purpose and heavy machine guns (amidships and offset starboard or elsewhere) and naval mines and depth charges (at stern dispensers). Widely used torpedoes of the time were the Mark 8 class type which were later replaced by the Mark 13 series. For close-in self-defense, the crew was afforded a pair of traversing, open-air machine gun positions (turrets) each fitting 2 x 0.50 caliber heavy Browning machine guns (prior to Pearl Harbor, these were hydraulically-operated turrets) and an optional Lewis 0.30 caliber machine gun could be mounted at the front. These could be used against both lightly-armored surface vessels or low-flying aircraft. Standardized heavy caliber weaponry included the excellent Swedish 20mm Oerlikon cannon series provided with excellent fields-of-fire and inherently strong reliability. Depth charges (300lb or 600lb versions) could be used against enemy submarines or pursuing enemy surface ships (usually enemy destroyers) while, similarly, naval mines could be dispensed in a similar fashion. A distinct "PT Gunboat" version appeared and these were ELCO boats stripped of their torpedo armament and instead completed with heavy caliber surface-minded cannon.
Despite these impressive armament loadouts, PT boat value went far beyond their offensive arrangements for the series proved equally effective in laying down swathes of naval mines to create perilous floating mine fields. The boats could also self-manufacture smoke screens through stern-mounted generators. PT boats also served in rescuing downed naval airmen or other personnel and were used to good effect in evacuating desperate ground forces from collapsing beachheads. Specialized missions for PT boat crews were a norm and its value in "counter-mine" operations was also notable. PT boats could further be assigned as dedicated raiders or reconnaissance elements.
PT boat armament soon went beyond the early standard-issue weaponry for many boats were modified in-the-field with a plethora of impressive armament arrangements. Boats were being fitted with deck mortars and rocket projectors as well as aircraft-type repeating cannons and field anti-tank guns. 37mm M3/M9 autocannons (aircraft-based weapons taken from available Bell P-39 Airacobra stores or field anti-tank gun versions) were being deployed on ELCO PT boats and, later, the excellent 40mm Bofors naval cannon was added to the mix. When these makeshift applications proved their worth in direct action, the USN made them standard fittings out of the gate. By the end of the war, the inherent firepower of PT boats was such that they rivaled the firepower of USN destroyers. A typical late-war ELCO PT could field deck mortars, 8-shot 5" rocket projectors, a Bofors 40mm cannon, an 37mm cannon, 2 x 20mm cannons, 2 or 4 x torpedoes 0.50 and 0.30 caliber machine guns - combinations of these on a single boat no less. It was not out of scope to find PT boats also fitted with captured Imperial Japanese Army ordnance in the form of 23mm anti-tank guns.
In operational service, PT boats were put through some very heavy paces, operating in rough waters and under intense danger and stresses. They were active during the massive Allied D-Day landings of Northern France where they were used to screen amphibious forces from marauding German vessels and further keep the English Channel free of enemy patrol/attack vessels. Control of Mediterranean waters was also key in the Allied advance on Italy and North Africa and PT boats were used to control shipping in the region - often clashing with German "E" and "S" boots (boats). However, records show that the PT was most active and in greatest numbers in the Pacific Theater where the series made such a name for itself against the Japanese Navy. It became such that IJN personnel feared attacks from these "small" warships to the point that they nicknamed American PT boats "Devil Boats". With the element of surprise in check, PT boats could engage nearly any enemy surface warship at range with torpedoes and close in for a timely kill with cannon if need be.
The biggest threat to PT crews lay in the patrolling enemy destroyers (equally well-armed vessels) and enemy seaplanes, the latter mostly active during the day and armed with depth charges and bombs. Such threats forced the PT to operate mostly at dusk, nighttime and early morning hours where natural lighting was at its minimum, relying on the prowess and training of the crew for ultimate success. It was not until later in the war that widespread use of radar aboard PT boats made night attacks ferociously effective and garnered the "Mosquito Fleet" an even greater reputation.
Of course no write up of PT boats would be complete without mention of one of the most famous boats of the class - this being the PT-109 which included then-sailor and future American president John F. Kennedy. PT-109 was severed by a Japanese warship with remaining portion of the vessel managing to stay afloat over 12 hours. The surviving crew eventually made their way to an uninhabited island, avoiding prowling sharks and Japanese patrols in the process. They were eventually recovered by allied Solomon Island scouts and made Kennedy are war hero. Of course not often mention of the attack was the death of crewmen Seaman Andrew Kirksey and Seaman Harold Marney and the injuries suffered by two others - all were heroes of the day.
PT-41 (a 77-foot ELCO) of RON 3 was used to evacuate General Douglas MacArthur along with family and staff from the falling Philippines Front - the action awarded Commander John D. Bulkeley (1911-1996) with the Medal of Honor, becoming one of the first PT servicemen to be honored as such. Today, less than a dozen PT boats are known to survive as most were destroyed by the US Navy immediately after the Japanese surrender. Despite the lack of PTs in existence and the stories of PT boat crews remaining largely overshadowed by other war stories, there is nothing to take away from the sheer courage and accomplishments earned by this group of fighting men.
ELCO of Bayonne, New Jersey, would go on to produce 326 PT boats of 80-foot length (total PT boat production of varying lengths by ELCO was approximately 385) during the span from 1942 through 1945. 296 are known to have served under the banner of the USN while a further 30 were delivered to the Soviet Union under Lend-Lease. A further 31 ELCO boats were contracted by the USN but never produced due to the end of the war - these contracts being cancelled in full. The ELCO 80-footer remained the most produced of all American PT boats of the war.
While the Huckins Yacht Company contributed some PT boat production in the war effort, the ELCO and Higgins PT boats became the standard PT boats of the US Navy during World War 2. The ELCO and Higgins boats shared some visual similarities but closer observation quickly revealed their differences - in particular a cockpit held well-forward behind a shorter bow (the ELCO had a cockpit closer to amidships, exposing more bow deck surface area). Higgins boats were also of the 78-foot PT-71 class though they displaced roughly the same as some of the ELCO boats. Both breeds, however, sported the same beam measurement and shared the Packard powerplants, internal systems, weapon fittings and cabin areas.