Tuesday, April 9, 2013

The Pacific War That Wasn't

Of the U.S. ships sunk at Pearl Harbor on December 7, 1941, what would have happened if the majority of them had survived the attack and gone on to meet the Japanese – or some other – fleet in a traditional naval battle? We’ll never know, of course, and good historians routinely caution against speculation of this nature. Yet with exactly this hypothetical question historian Trent Hone begins his article on “The Evolution of Fleet Tactical Doctrine in the U.S. Navy, 1922 – 1941” in The Journal of Military History.

Of course, it is merely a rhetorical device, meant to grab the reader’s attention; it succeeds. Having gotten our attention, Trent Hone wishes to explore the a question more appropriate to a serious historian: what did Navy officers envision as a naval battle during the pre-war years? By war’s end, submarines and aircraft carriers would assume a much greater role. But the Navy, which began its glory years with Teddy Roosevelt’s “great white fleet,” had three or four decades of battle planning prior to Pearl Harbor’s destruction. What were they planning?

One main feature of their tactics and strategies involved fleet formations. A fleet is composed of various types of ships: battleships, cruisers, destroyers, tenders, and other types of ships. Naval vocabulary is a world unto itself, and worth exploring: a battleship is the largest and heaviest of the traditional naval vessels, heavy with arms and heavy with armor, introduced after the end of sailing ships and with the advent of the steam, coal, and oil era; a cruiser is small and light, lightly armed, and lightly armored, and therefore very fast; a destroyer is even faster, smaller, and lighter; the battlecruiser has light armor but heavy arms, allowing it to be faster than a battleship; a tender supports or supplies other vessels. There are many other classes of boat, including: armored cruiser, aircraft carrier, gunboat, heavy cruiser, monitor, pocket battleship, submarine, and torpedo boat – to name but a few. Within these categories, one can distinguish, e.g., between pre-dreadnought and post-dreadnought battleships, or between light cruisers and heavy cruisers.

The formation of a fleet, consisting of some combination of the above-named categories, is crucial to its success. In years between WWI and WWII, the Navy designed formations for three situations: cruising, approach, and battle. A ‘cruising’ formation is mainly for transporting the fleet from one place to another, in conditions when “the chances of contact were slight.” An ‘approach’ formation was for exactly that: approaching the enemy. Likewise, a ‘battle’ formation was for actually engaging the enemy.

Designing a formation was one thing. Carrying it out was another. Two key variables were necessary to executing a formation: a steady course, and the ability to turn. A steady course was dependent on technology: accurate maneuvering, and the ability to maintain a consistent speed; the slowest vessel in the formation determined the maximum speed of the formation; wheelhouse and rudder skills determined how consistent and how tight the formation could be. Turning was a complex activity: to turn one ship is easy; to keep a specific formation while turning an entire fleet is an exercise in vector physics. The answer to the question of turning was circular, or semi-circular, formations based on a series of arcs.

A steady course was important, not only for keeping formation, but for calculating precision firing from the heavy guns. For the most accurate firing, a ship had to keep constant speed and direction, with a minimum of pitch, yaw, and roll. Even so, the skills required for accurate fire included algebra, trigonometry, and calculus.

The U.S. Navy enjoyed a set of advantages, relative to the navies of other nations, in the 1920’s – the technological construction of their ships incorporated the best designs of guns and armor; aerial spotting increased the range of effective fire by many thousands of yards; fire had been organized by ‘director control’ in which all the guns of battle ship fired on the orders of one officers, and by ‘massed fire’ in which all the guns of a number of ships fired on the orders of one officer; the development of a computer – analogue, to be sure – which sped up the calculations; and an emphasis on arming ships with the most powerful sixteen-inch guns.

In this same decade – the 1920’s – the Navy dealt with two disadvantages: first, the elevation of its big guns was limited, keeping them from longer ranges; second, the speed of the fleet was slow.

In the next decade – the 1930’s – the Navy dealt with these disadvantages. The elevation of guns could be improved on existing ships, and new ships could be built so that their guns reached higher angles. Dealing with a slow average fleet speed was a thornier problem. Although newer ships could be constructed with faster capabilities, any group of ships was still limited by its slowest, and usually oldest, ship. This difficulty was resolved by new plans for formations and maneuvers. One innovation was the ‘reverse action’ in which the Navy’s ships would steam past the enemies ships, moving in the opposite direction – i.e., if the enemy boats were moving southward, the Navy boats would move northward. This increased the relative speed of the ships, making up for the Navy’s slower speed. This tactic was never put to any conclusive test, so it remains an innovation in theory.

Surveying the years from 1922 to 1941, Trent Hone generates a description of the Navy’s tactical doctrine: first, its goal was to have a definite plan for various situations – no improvising. Second, tactics were structured around known American advantages – powerful guns and strong armor – and known enemy disadvantages – possible opponents might lack the long range of American guns. Third, despite the goal of having plans for various types of situation, there was also an element of flexibility and decentralization; a battle plan was a ‘framework’ within which officers could apply ‘their own initiative.’ Fourth, the Navy wanted to seize the tactical initiative, not by means of the speed which it lacked, but by means of complex and unexpected maneuvers – e.g., the ‘reverse action.’ Fifth, long-range fire supported by aerial spotting became a clear preference of naval officers; the addition of airplanes made the guns much more effective. Sixth, aggressive offensive action concentrated on the enemy battle line, not only with powerful guns, but with airplanes bombing, dive-bombing, and launching torpedos was given primary effort in battle scenarios, as opposed to more cautious and conservative battle plans which devoted more resources to defensive maneuvers. Trent Hone continues his article by describing how new ships – the North Carolina and the South Dakota – were built with the Navy’s tactical doctrine in mind, featuring big guns with high elevation angles, high-tech armor, and higher speeds.

The Navy’s doctrines from the pre-1941 era were never really tested in combat. Hone closes his article by reviewing some battle plans and war game notes from mid-1941. How such battles – presumably against the Japanese – would have ended remains forever unknown.