Part One: Torpedoes Through the Thirties
Frederick J. Milford
Dr. Milford retired from Battelle Memorial Institute in 1989 as Vice President for Special Projects. He is a life member of the Naval Submarine League.
Torpedoes have two very important claims to fame: they were the first guided missiles, and they have probably sunk more ships than any other naval weapon. Further, from the viewpoint of sub surface warfare the torpedo has always been the major offensive weapon of submarines and during WWII it began its development into the pre-eminent anti-submarine weapon. In spite of this, the literature on torpedoes is skimpy. This series of papers is an attempt to chronicle the evolution of U.S. Navy torpedoes, especially self-propelled or automobile torpedoes, from the earliest weapons to those currently deployed. Serious attempts have been made to construct technically correct, but readily understandable explanations of critical aspects of torpedo performance and, at the same time, to avoid some of the glib explanations that have sometimes appeared elsewhere.
American Underwater Weapons Before 1869
During the Revolutionary War attempts were made by the colonial naval forces to use underwater explosives in attacks by TURTLE against HMS EAGLE in 1776 and possibly HMS ASIA in 1775. Also, floating kegs of gunpowder were launched upstream of Philadelphia in a vain attempt to damage British ships in the harbor. Underwater explosive devices were extensively used by the U.S. Navy during the War of 1812, but had little impact other than to provoke vitriolic letters in the public press.The Civil War produced Farragut’s famous “Damn the torpedoes! Captain Draton, go ahead Jouett, full speed!” Of course, he was talking about stationary torpedoes or what would now be called mines. Spar torpedoes were also used with some success and attempts were made to use towed torpedoes. Confederate torpedoes of all types, mostly mines, sank 29 Union ships and damaged 14 others thus sinking more Union ships than all the rest of the Confederate States Navy. The Confederate Navy suffered one ship sunk, the modem ironclad ALBERMARLE, and five damaged by Union torpedoes.
After the Civil War the U.S. Navy entered a period of decline that lasted until the birth of the New Navy of the United States in the early 1880s. During this period of decline, in what must be viewed as a small but significant counter-current and quite possibly a response to the losses incurred during the Civil War, the U.S. Naval Torpedo Station at Newport, Rhode Island was established.
U.S. Navy Automobile Torpedoes
Early Attempts to Acquire Automobile Torpedoes. When the U.S. Naval Torpedo Station, Newport, Rhode Island was established on Goat Island in 1869 it was the first establishment in any navy devoted primarily to the development to torpedoes. The NTS was established at low cost even by the standards of the then impoverished U.S. Navy-the island already belonged to the Federal Government and existing buildings were used. The general mission was the development of torpedoes, torpedo equipment, explosives and electrical equipment. Improvements in spar torpedoes and stationary torpedoes (mines) were the first projects.
The initiation of work on automobile torpedoes (movable torpedoes in the language of the day) at NTS was described by Lieutenant Commander Royal Bradford as follows: .. In 1869, after the appearance of the Whitehead torpedo, an attempt was made at this Station to construct one similar in principle, so far as known.” The objectives were loosely stated as:
“To go under water for a considerable distance at a fair rate of speed.”
“To make a straight course and maintain a constant immersion, whether started at the surface of the water or any point below it.
The design that emerged was externally very similar to the contemporary Whitehead torpedo, fusiform, 14 inches in diameter and 12-1/2 feet long, a little shorter than the Whitehead torpedoes. The principal interior difference seems to have been in the engine which consisted of two cylinders (2 inches by 4 inches) with their axes parallel to the torpedo axis. The piston crossheads engaged in sinusoidal groove cut in the surface of a drum which converted the linear motion of the pistons to rotary motion of the drum. The drum was geared through a 3.S to 1 reduction to the propeller shaft. By comparison, the contemporary Whitehead torpedo used a two cylinder, oscillating, 90 degree vee engine. The first NTS Fish Torpedo was tested in 1871. As Bradford says “Generally speaking, the results of the trials were unsatisfactory, though the diving apparatus worked reasonably well”. The difficulties were a hull that was not watertight, an air flask that was not air tight and an inadequate engine which, collectively, seem to make Bradford’s comment at least an understatement. Attempts to remedy these shortcomings were made in a second torpedo which was tested only at pierside. On the basis of these two torpedoes, plans for a fish torpedo were prepared by Lieutenant Barber and submitted to the Bureau of Ordnance in June 1874. Though the torpedo was not fully successful, it was an auspicious start. The submission of plans to the Bureau is, however, the end of the known record of the NTS Fish Torpedo.
From 1874 until 1891 the development of automobile torpedoes for the U.S. Navy was in the hands of innovative private inventors. The NTS Newport budget was meager and its role in these developments was basically to provide test and evaluation facilities. On a worldwide basis, there were well over a dozen of these inventions. Some were the fruits of the genius of great inventors of the day; others were produced by unknowns. Great ingenuity is evident and some contain the seeds of developments that subsequently became central to torpedo development. Three of these precursors that are particularly interesting are the electric torpedo, wire guidance and the rocket torpedo. None of these, however, found their way into the U.S. navy torpedo inventory at the time. Several inventions were submitted in response to a circular letter and subsequently evaluated in detail by the U.S. Navy Torpedo Board in 1883. Of these only the Howell torpedo, which is discussed below, was any sort of success. At this point in time, 1884, the U.S. Navy did not have a usable automobile torpedo, whereas by 1881 about 1500 Whitehead torpedoes had been sold to other navies and by 1884 Whitehead and Schwartzkopf together could probably have produced close to 1000 torpedoes per year.
In addition to the indigenous inventive efforts, the Whitehead torpedo was at least twice offered to the U.S. Navy: in 1869 for $75,000 and in 1873 for $40,000. These offers were declined. Stolen plans and specifications were also offered, and may have been given to the U.S. Navy, by an employee of the Woolwich Arsenal. It appears that in any case the plans were of not real significance in the development of U.S. torpedoes. The full story surrounding the offer and the alleged delivery of the plans would be interesting, but only fragmentary comments have been published.
The Howell Torpedo. The Howell torpedo was developed by then Lieutenant Commander John A. Howell beginning in 1870. The development was completed in 1889 and the U.S. Navy ordered 50 Howell torpedoes from Hotchkiss Ordnance Co. in the same year. These seem to be the only production Howell torpedoes that were built. There were, however, other Howell demonstration torpedoes. The torpedo entered service in 1890 and was the U.S. Navy’s only torpedo until Whitehead torpedoes produced by Bliss and Williams came into service around 1894. Howell torpedoes continued in service into the 20th century. In his 1903 report the Chief of the Bureau of Ordnance reported that there were still 36 Howell torpedoes (as compared to 258 White- head type) on hand and the Inspector of Ordnance at NTS reported issuing 10 to USS IOWA as she was then the only ship still using them. Although development was slow and its service life short, the Howell torpedo was initially one of the few credible competitors to the Whitehead torpedo and elicited interest in other countries and favorably comment as late as 1945.
The Howett torpedo went through several stages of development. The first proposed version was, even by 1870 standards, very small, about 12 inches in diameter and 48 inches long. It was equipped with propellers at both ends which were on a common shaft together with a cylinder that contained the explosive charge. The whole rotating assembly, except, of course, for the propellers, was contained in an exterior cylindrical shell. The rotating assembly was given a spin with high angular velocity, thus storing energy for propulsion, and then launched. 11 This proposal was presented to the Bureau of Ordnance in June 1870 and referred to NTS for evaluation. The evaluation was unfavorable, but the Bureau permitted Howell to build a small model.
The model ran well enough that Howell, at his own expense, made a full sized torpedo. This also ran, but Howell concluded that having the axis of the flywheel (the rotating charge in these early devices) parallel to the torpedo axis was faulty in principle.
The propulsive arrangement was changed to use a flywheel on a shaft perpendicular to the torpedo axis to store energy and development of the Howell torpedo continued with gradually improving performance. The main virtues of this torpedo were good course keeping and the absence of a tell tale wake. The service torpedo, which was designated the Howell Torpedo Mark 1, was 14.2 inches in diameter, 129.75 inches long and carried a 96 pound charge 400 yards at 25 knots.
Early USN Whitehead and Bliss-Leavitt Torpedos 1891-1906.
Even as the Howell torpedoes were entering the U.S. Navy inventory, arrangements were being made to procure Whitehead torpedoes. In an interesting arrangement Bliss and Williams (later known as E.W. Bliss and Co.), rather than the U.S. Navy, negotiated a contract with Whitehead that provided drawings, sample torpedoes and a manufacturing license. Bliss, however, had only one customer for its Whitehead torpedoes, the U.S. Navy. The final capitulation and switch to Whitehead torpedoes was probably caused by two factors: objectively, the range and speed characteristics of Whitehead torpedoes were somewhat superior to those of the Howell torpedo and offered significantly greater growth potential. More subjectively, all other major navies were using Whitehead or Schwartzkopf torpedoes thus causing a definite risk that the U.S. Navy would be left behind if only Howell torpedoes were acquired.
E.W. Bliss and Co. produced five varieties of Whitehead torpedoes for the U.S. Navy: 3.5 meter Mks 1, 2, and 3, and 5.0 meter Mks 1 and 2, all 17.7 inches (45 cm) in diameter. The propulsion systems were compressed air powered, three cylinder, radial Brotherhood pattern engines. All used standard Whitehead pendulum and hydrostat depth control systems and the 5.0 meter Mks 1 and 2 and the 3.5 meter Mk 3 had Obry gyros for course control. Another, often overlooked, Whitehead torpedo was used by the U.S. Navy at this time, namely, the Whitehead 5.0 meter Mk 1A which was purchased directly from White-head. Though it was slightly different in detail, it was operationally interchangeable with the 5.0 meter Whitehead Mk 1 produced by Bliss (fewer than SO 5.0 meter Mk 1A torpedoes were purchased). A total of 438 of these very standard Whitehead torpedoes were procured. Very similar torpedoes were used in all the major navies at that time.
The torpedo project engineer at E.W. Bliss and Co., Frank McDowell Leavitt saw room for improvement in the Whitehead torpedoes and proceeded to develop what came to be known as the Bliss-Leavitt torpedoes. The distinguishing technical features of these torpedoes as compared to the Whiteheads were, larger diameter (21 inches), turbine engines, alcohol fired dry heaters and higher pressure air. Operationally the Bliss-Leavitt torpedoes had larger warheads and much longer range, 4000 yards @ 27 kts for the Bliss-Leavitt Mk 2 vs. 1500 yards @ 28.5 kts for the best U.S. Navy Whitehead (5.0 meter Mk 2.). The first Bliss-Leavitt torpedo, Mk 2, had a two stage, single wheel turbine which produced an unbalanced torque and unwanted gyroscopic effects. Mks 2 and 3 had two counter-rotating turbine wheels which eliminated both problems. In all three the turbine axis was parallel to the torpedo axis. The use of chemical energy, the heat of combustion of alcohol, was a great innovation, but similar innovations were being made by both Whitehead and Armstrong at about the same time. Approximately 750 Bliss-Leavitt torpedoes, Mks 1 through 3, were procured by the U.S. Navy. They entered service between 1904 and 1906 and remained in service untill 1922.
Three Decades of Torpedo Development 1908-1938. Twenty-one inch torpedoes were suitable for launch by large surface ships, but they were too heavy and too bulky for the torpedo boats, destroyers and especially the submarines of the day. Four new 17. 7 inch torpedoes were designed to address this problem. The Bliss-Leavitt Mk 4 was similar to the Mk 3, but designed especially for submarines. Mk 5 was a Whitehead design produced by Vickers and by the new torpedo factory at Newport. One of three speeds could be selected and set, but this had to be done before the torpedo was loaded into the tube. The power plant was a dry heater system using a four cylinder reciprocating engine, the last piston engine used in U.S. torpedoes until the Mk 46. The Bliss- Leavitt Mk 6 introduced a new turbine configuration in which the wheels were horizontal. This configuration has been the most common choice for U.S. Navy torpedo turbine systems ever since.
The Bliss-Leavitt MJc 7 was the last 17. 7 inch torpedo acquired by the U.S. Navy, but it was a milestone. It introduced cooling of the combustion chamber by spraying water into it in addition to the fuel and air. The resulting mixture of steam and combustion products was a better working fluid for the turbine than heated air and dramatically improved the range. Another first for the Mk 7 was the use of TNT in the warhead. In addition, this torpedo could be launched from submarines or destroyers and was used later in experimental air launchings. The Mk 7 entered service in 1911 and with many modifications remained in service in older submarines through 1945. After 1922 it was the only U.S . Navy 17.7 inch torpedo in service.
Marks 8 through 12 were 21 inch steam, turbine powered torpedoes, with the same general features as described above, differing mainly in detail. Mk 9 was the last torpedo manufactured by E.W. Bliss and Co. and the Mk 10 was the last designed by them. Both functions were taken over entirely by the Newport Torpedo Station effective l July 1923 and no new U.S. Navy torpedoes, or even piece parts for torpedoes, were designed or produced by any other U.S. Navy establishment or industrial firm until 1940 when NTS Alexandria resumed operations and began producing piece parts. Mk 11 introduced multiple speeds that could be selected after loading into the tube. All of these torpedoes, Mks 8 through 12, remained in service through 1945. The Mk 8, in particular, was the standard weapon for the flush deck destroyers DD 75 through DD 347). Just outfitting these ships required over 3000 torpedoes and this was certainly a production record until WWII. Mk 8 was also extensively modified during its long service life; Mk 8 Mod. 8 was the last major modification of this remarkable weapon. Marks 11 and 12 were pure NTS products, but altogether only a few hundred were built.
Beginning in 1915 with a contract with Sperry Gyroscope Company and continuing sporadically at NTS 25 after 1918 attempts were made to develop an electric torpedo. These efforts led to three development torpedoes Electric Torpedoes Mk 1 and Mk 2 and the Mk 20. None of these were issued as service weapons. As compared to the steam torpedo program, this was not a major effort.
The trio Mk 13, Mk 14 and Mk 15, which completed development in 1936, 1931 and 1935 respectively, had a great deal in common and are justifiably famous as the workhorses of WWII. The object in designing these torpedoes was to provide a modem weapon for each of the three platforms, aircraft, submarines and surface vessels. These designs were to take account of all that bad been learned in the development and production of earlier weapons particularly Mks 7 through 12 and wherever possible improve performance. The development took place at NTS Newport during the period of that station’s total torpedo monopoly. Furthermore, through that period NTS seems to have operated in what was almost total technical isolation and certainly a complete competitive vacuum. As noted above, from 1923 on, only NTS Newport bad designed or built torpedoes for the U.S. Navy. Neither the Mk 11 nor the Mk 12, the two earlier entirely NTS designed and built torpedoes, had, however, been produced in large quantities or become important service weapons.
The common features of the three new torpedoes were the turbine and other mechanical parts of the propulsion system, the depth engine and gyro and the contact part of the exploders. The Mk 13 was the first torpedo developed by the U.S. Navy specifically for launching from aircraft. It was shorter and larger in diameter (22.5 inches) than either of the other two. Its maximum speed was lower, 33.5 kts vs. 46.3 kts for the Mk 14 and 45 kts for the Mk 15 The lower speed had important consequences as we shall shortly see! Also, the Mk 4 exploder used in the Mk 13 torpedo did not contain the magnetic influence feature that was deemed so important in the Mk 6 exploder used with the other two torpedoes. Externally the three torpedoes were different to suit the different platforms. The Mk 13 structure was also designed to survive an air launch from 50 feet at 100 kts and thus somewhat more rugged than either of the other two, however, for the higher altitude and greater air speed launches that became important in WWII accessories were required to maintain satisfactory aerodynamics and prevent damage on water entry.
The mechanical parts of these weapons were beautifully made but the mechanisms seem excessively complex. It is difficult to appraise this complexity without attempting an alternative design within the framework of 1930s design practice, but it is also difficult to escape the feeling that these devices are yet another example of arcane instrument engineering as practiced by BuOrd without competition from other design teams. In their defense it must be noted that there were very few, perhaps only one (structural failure of the contact exploder), purely mechanical problems that were not quickly found and easily fixed.
What does seem to have been overlooked is the effect of increased speed on details of the hydrodynamics and on the inertial forces experienced by torpedoes. The first led to a significant depth control problem in the Mk 10 and was exacerbated by a factor of about two by the increased speed of the Mk 14. The second led to the structural deformation and attendant failure of the contact portion of the Mk 6 exploder. An entirely separate problem was the failure of the magnetic influence portion of the Mk 6 exploder. These problems, which were particularly acute in the Mk 14 submarine launched torpedo, are discussed in the next part of this series.