A review of naval gunnery technology in the Twentieth Century and its effects on tactical naval game design. Introduction The Admiralty Trilogy is a family of related tactical naval warfare simulations that span the 20th century. The principle goal of the designers was to faithfully illustrate how naval warfare has developcd over the past 100 years in a complete, yet easy to use miniatures combat system. Within each of the three subsystems, Fear God & Dreadnought Command at Sea, and HARPOON4, naval gunnery plays an important, but varying role. In modeling gunnery performance as it advanced over the years, it was necessary to examine the evolution of the technologies that drove those improvements. This article is a brief summary of the technological developments used in defining the state of naval gunnery, or the gunnery standard, for a specific period of time. The boundaries for a particular gunnery standard were established when a number of these technologies had reached a higher level of sophistication and were in widespread use on naval combatants of that time. Gunnery Standard 1: The Pre Dreadnought Era 1900-1909 The lower limit of 1900 was chosen because by this time all the technologies that defined modern naval gunnery were, more or less, fully integrated into the design of the surface combatants of that day. The fact that it was also the beginning of the 20th century made it somewhat convenient as the lower boundary. From a technological standpoint, however, it would be possible to go back four more years (1896) and still meet the conditions of this gunnery standard. The upper boundary was determined by when the first dreadnoughts actually entered operational service. By 1909, the Royal Navy had four dreadnoughts in service with another five in various stages of fitting out. The U.S. Navy had its first two dreadnoughts in service and the Germans had their first two undergoing sea trials. By 1910, the dreadnought battleship/battle cruiser had become the dominant ship type in all major navies and, in several minor navies as well. This period's gunnery technology standards are as follows: a) High velocity guns using smokeless powders. Between 1886 and 1890, a number of smokeless powders were perfected by French, Swiss, and English chemists. Large caliber naval guns (11+ inches) using these powders were first introduced on pre-dreadnought ships around 1895. These powders, because of their slow burn rate in comparison to black powder, generated sustained, high combustion pressures within the gun barrel that resulted in high muzzle velocities (greater than 2,300 ft/sec). Such velocities were necessary to penetrate the new face hardened or cemented steel armor. b) Low elevation guns ( less than or equal to 20 degrees). During this era, "long range" gunfire was considered to be at ranges of about 8,000 to 10,000 yards. While this was a significant improvement over the earlier battle practice ranges of 2,000 yards, this improvement was more of a tactical innovation which didn't require guns with a higher elevation capability. c) Optical range finders, 4.5 to 7.0 feet, are fitted on many major combatants. In 1893, the British optical company, Barr & Stroud, introduced the Royal Navy to the coincidence optical range finder. By 1895, the Royal Navy had purchased a large number of FA Mk 1 devices. The German optical instruments manufacturer, Carl Zeiss, introduced the stereoscopic optical rangefinder around 1906 for naval applications. By 1904, optical range finders were widely available and usually fitted on most naval combatants. During the Russo-Japanese War, both sides used Barr & Stroud FA Mks 2&3 range finders on board their ships. d) Independent gun laying. During this time frame, a combatant's main guns were aimed and fired by their individual gun captains. Captain Percy Scott, RN would do most of his experiments on director-based central firing during this time, but it would not be accepted in the Royal Navy until about 1912. However, Captain Scott's work on the concept of "continuous aim" gunlaying significantly improved gunnery accuracy by enabling a gunlayer to maintain his sights on the target despite own ship's movement. e) Shells with 2 - 4 CRH and armor piercing caps are used. Naval shells during this time were rather blunt and had head lengths between 2 - 4 calibers radius head (CRH) long. The head length was measured from the tip of the shell to the point where the mid-body became cylindrical. These shells, because of their poor aerodynamic shape, had relatively high drag coefficients which limited their maximum range and armor penetration capability. By this time, all armor piercing shells were also fitted with a specially designed cap which improved the shell's ability to survive a high velocity impact. This considerably enhanced the shell's armor penetration capability and was absolutely necessary if face hardened armor was to be defeated. Gunnery Standard 2: The Dreadnought Era 1910-1924 By 1910, the dreadnought battleship was the new queen of the seas and the battle fleets of WW I were built around them. While the number of big guns on the ships was significantly increased, there was little improvement, except for the steady increase in bore size, in the design of the large caliber guns themselves. From a tactical point of view, however, the concept of just what was "long-range gunnery" would undergo considerable change as improvements to the torpedo's range and speed pushed the required engagement ranges beyond 10,000 yards. After WW I, the war-torn economies of Europe could not sustain a robust naval construction program and the Washington Naval Treaty of 1922 slowed new construction down to a mere handful of ships. In addition, under the terms of this treaty, major modifications to a battleship's main armament were not permitted. The gunnery standards for this period are: a) High velocity guns using smokeless powders. No change from the previous standard. b) Low elevation guns (less than and equal to 20 degrees). No change from previous standard even though the expected maximum engagementrangc doubled to about 16,000 to 22,000 yards. These longer engagement ranges were driven solely by the improvements in optical range finders and the introduction of analog fire control computers. No technical modifications to the guns themselves were required to achieve the greater ranges. C) Optical range finders, 9.0 to 15.0 feet, are available. In 1912, the last of the major navies (Imperial Germany) purchased and installed optical range finders on their ships. The length of optical range finders was increased as a result of the tactical necessity to engage torpedo-armed ships at ranges beyond 10,000 yards. As range error for optical range finders is inversely proportional to its length, longer baselines were developed to provide the range information necessary for accurate gunnery out to at least 16,000 yards. d) Crude fire control systems are introduced. Analog computing devices were introduced that take a range finder's data and use it to predict the target's course, speed, bearing, and range. The estimated target position is then used to derive the appropriate bearings and elevations of the guns which will cause a salvo to straddle the target. e) Central director gun laying. Captain Percy Scott's experiments on director-based central aiming clearly showed its superiority over independent gun laying and was accepted by the Royal Navy around 1912. Other navies followed suit, although with procedural modifications of their own. The Royal Navy also adopted director-based firing of the main guns but this was not universally accepted by other navies. f) Shells with 2 - 4 CRH and armor piercing caps are used. No change from the previous standard. Gunnery Standard 3: The Treaty Years 1925-1934 Naval activity during this period was dominated by a number of treaties that limited the construction of virtually all types of naval combatants and severely restricted modifications to the guns on, existing dreadnoughts. However, improved fire control systems with stable vertical elements and even longer basefine optical range finders were installed on many battleships by 1925. The 1934 limit, marks the end of these restrictions when Japan declared it would no longer abide by the terms of the various treaties. a) High velocity guns using smokeless powders. No change from the previous standard. b) Mostly low elevation guns (less than and equal to 20 degrees). As the Washington Naval Treaty didn't allow major modifications to a ship's main armament, the only large caliber guns with high elevation angle capability were those on the few new construction battleships. Thus, most of the guns during this time period had the same elevation and therefore, range capability as during WW I. c) Optical range finders, 25+ feet, are available. The major naval engagements during WW I showed that future gun battles could take place at 20,000+ yards. To hit a battleship at these ranges would require even larger baseline range finders to provide accurate targeting data. d) Fire control systems with stable vertical elements are introduced. The Battle of Jutland opened the eyes of the Royal Navy to their need for an accurate fire control system if they were to win long range gunnery duels. The poor performance of the existing Dreyer tables and the need to sense own ship's motion led to the incorporation of a local stable vertical element into the newer fire control systems. Ironically, the fire control system offered by British inventor Arthur H. Pollen, incorporated a stabilized range finder and a vertical element in its design and was available prior to WW I. Unfortunately, due to significant personality conflicts, the Royal Navy's reluctance to accept useful modifications from outside its own organization, and its fiscal stinginess in the area of fire control, led the navy to adopt the inferior Dreyer system. Only the Imperial Russian Navy purchased the entire Pollen Argo Clock system for its dreadnoughts and pre-dreadnoughts and this fact helps to explain the accounts of the incredibly accurate long range gunnery of Russian units in the Black Sea. e) Modified central director gun laying. By this time, most navies had the main guns pointed on target via a centralized fire control organization. However, there were a variety of techniques used in the actual gun firing procedures. Firing all the guns at once, from a centralized location, was no longer deemed to be the most accurate method as the salvo's dispersion increased and made spotting more difficult. Going to partial salvos made spotting easier and reduced the salvo dispersion, but this required individual guns on a turret to be fired independently. This reduced the statistical chance of a hit as the ship was essentially firing two separate salvos instead of one. The split salvo alternative was based on the staggered firing of all the guns on a turret. Each gun in the same position on each turret was fired simultaneously followed by the remaining guns at preset intervals. This method reduced salvo dispersion while maintaining the desired rate of fire. Unfortunately, until a reliable delay coil could be manufactured and placed in the firing circuit, the guns had to be fired manually. f)Shells with 5 - 7 CRH and armor piercing caps arc used The concept of plunging shell against the relatively weaker deck armor became quite popular during this time, as evidenced by the formal introduction of the Immunity Zone to fleet tactics. However, to obtain the necessary range to support plunging shell fire (greater than 20,000 yards) with existing gun systems, more aerodynamic shells were needed. This led to armor piercing shells having increased head lengths of 5-7 CRH. Shells with 57 CRH head length have a drag coeffident that is about 50% less than earlier shells with a head length of 2-4 CRH. With this reduction in shell drag, the maximum range ofa large caliber gun was increased, on average, by about 25%. Gunnery Standard 4:'TheWorld War II Era 1935-1945 With the abrogation of naval treaties, the major navies of the world began a period of intense modification of existing ships, as well as the commencement of new construction programs. Advancements in fire control, gun elevation angle, and the introduction of radar pushed engagement ranges out beyond 30,000 yards. Many of these improvements were at sea shortly after 1935, with the exception of radar which would require a few more years to mature. The 1945 limit is based on the end of WW II and the final ascendancy of the aircraft carrier to the throne of naval warfare. a) High velocity guns using smokeless powders. No change from the previous standard. b) Mostly high elevation guns (greater or eaual to 30 degrees). With the Washington Naval Treaty no longer in effect, most remaining WW I battleships had their main guns modified to allow for elevation angles of at least 30 degrees. New construction units had gun mounts that were designed from the start to support elevation angles of 40 degrees or more. With these modifications, large caliber naval guns could now engage targets at ranges well beyond 25,000 yards. c) Optical range finders, 25+ feet, are standard. No change from the previous standard. d) Radar gunfire directors. By the beginning of WW II, many navies were finished with their radar experiments and had begun fitting their ships with systems to provide very accurate range data, especially at long ranges and in poor visibility. These early radar systems, however, were inferior to optical systems in providing bearing information. e) Improved fire control systems with stable vertical elements. The second and third generations of analog computers, with stable elements, were perfected and deployed during this time period. Improved gear designs, with tighter machining tolerances, and more sophisticated mathematical algorithms, provided the necessary physical components which enabled these computers to accurately aim the guns against even a maneuvering battleship at long range. Radar data was also, in many cases, fed directly into the fire control system via complex synchro mechanisms. f) Central director gun laying. With the introduction of accurate time delay coils into the main battery firing circuits, director-based central firing of the guns became the norm for most navies. Local control of the guns was retained as a secondary capability should the director be damaged or destroyed by enemy gunfire. g) Shells with 7 - 10 CRH and armor piercing caps are used. With the increase elevation angle of large caliber guns making engagements at 30,000+ yards possible, shells had to be even more streamlined. Although the rcduction in drag was nowhere near as large as with earlier changes, it was sufficient to enable these new shells to reach ranges in excess of 35,000 yards. More importantly, however, with the reduced aerodynamic forces the shells wobbled less in flight, making for tighter salvo patterns. Gunnery Standard 5: The Eclipse of the Big Gun 1946-1959 With the end of WW II, the major powers began a large scale demobilization of their navies. The huge resource requirements of a large navy could not be supported by war-weary nations. In addition, the aircraft carrier had shown itself to be supreme during the war and with the advent of atomic/nuclear weapons, large capital ships were considered to be vulnerable and obsolete. Therefore, during this period surface gunnery became stagnant. There were some advances in fire control, particularly in antiaircraft systems, but for all intents and purposes, few improvemcnts were made to the guns themselves. The 1959 limit is based on the introduction of the guided missile, which would supplant guns in both antisurface and antiaircraft roles. a) High velocity guns using smokeless powders. No change from the previous standard. b) Mostly high elevation guns (greater than and equal to 30 degrees). No change from the previous standard. c) Optical range finders, 25+ feet, are standard. No change from the previous standard. d) Radar gunfire directors By the end of WW II, radar gunfire directors with a blindfire capability were now the norm. These new radar systems had narrower beams which allowed them to accurately determine the target's bearing as well as its range. e) Improved fire control systems with stable vertical elements. No change from the previous standard. f) Central director gun laying. No change from the previous standard. g) Shells with 7 - 10 CRH and armor piercing caps are used. No change from the previous standard. Gunnery Standard 6: The Missile Era 1960 - Present Beginning in 1960, radar guided antiship cruise missiles were deployed by the USSR on destroyers and small fast patrol boats. With the sinking of the Israeli destroyer Eilat in 1967 by Egyptian SS-N-2A STYX missiles, the gun was formally replaced by the guided missile as the primary shipboard weapon. Thereafter, the gun played a secondary role in both anti-surface and anti-air warfare. As the gun's role atrophied, there was a concomitant reduction in bore size to the point where today a naval gun with a bore of 130mm is considered large. Even with the short-lived recommissioning of the Iowa class battleships in the early 1980s, the 16-inch gun was still considered to be a secondary armament to the Harpoon and Tomahawk missile batteries (although this distinction would probably be lost on any target within 16-inch gun range). Gunnery Standards and the Admiral Trilogy Defining the key technologies that influenced the performance of naval gunery was essential if a historically accurate model was to be created. Each of the gunnery standards was carefully reviewed to determine which technologies deserved to be captured as hit modifiers, rule limitations, or data annex characteristics. While there are other factors that affect gunnery performance, such as barrel wear, they were either assessed to be a minor contributor on a tactical game scale or their effects could not be isolated and thus, historically proven. In assigning a gunnery standard to a specific trilogy rules set, a number of the technologies had to have reached the next level of sophistication and had to be in use by the majority of naval combatants of that time. Given this criterion, the following is the breakdown of the gunnery standards with respect to the applicable game within the Admiralty Trilogy system. Each gunnery standard will be supported by the rules and data annexes of the appropriate game. a) Fear God & Dreadnought Gunnery Standards 1 & 2 (1900 - 1924) b) Command at Sea: Gunnery Standards 3, 4, & 5 (1925 - 1959) c) Harpoon: Gunnery Standard 6 (1960 - Present) Armor Piercing Cap Optical Range Finder BT Back to The Naval Sitrep #12 Table of Contents Back to Naval Sitrep List of Issues Back to MagWeb Master Magazine List © Copyright 1997 by Larry Bond and Clash of Arms. This article appears in MagWeb (Magazine Web) on the Internet World Wide Web. 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