The Specter of the Gun

USS Zumwalt (DDG 1000)

     The DDG 1000 has again appeared in recent news. Its secondary armament was in the spotlight earlier this month as the ship’s Program Manager CAPT Jim Downey discussed the change in the ship’s close in gun (CIG) system. Downey said the planned MK 110 57mm gun did not meet expected standards of lethality while the MK 46 30mm weapon exceeded them. A recent Daily Beast article suggested the ship’s stability remained uncertain. These articles provide snapshots of possible problems, but more detail is needed to accurately assess the potential warfighting capabilities and limitations of the DDG 1000. It represents a remarkable number of both “returns” and “firsts” in warship design. The big question is whether or not the ship can overcome some significant potential flaws by exploiting its revolutionary technological advances.

DDG 1000, Note pronounced tumblehome hull form

      While discussion continues on the CIG, there is much less talk on the imminent introduction of the largest naval gun to enter active U.S. naval service since the Second World War. The 155mm Advanced Gun System (AGS) has undergone development since the early 1990’s as a component armament of the SC-21 family of warships. During this “high noon” of the American “unipolar moment”, there was much more attention toward achieving long-range, coordinated “fires” than concern about the sea control that made such activities viable. How effective can an AGS with a nominal range of 24 nm (nautical miles) for conventional shells and 63 nm for advanced long range land attack projectiles (LRLAP) be in an environment of advanced anti-access/area denial (A2AD) capabilities? The AGS is perhaps useful in attacking isolated locations outside an opponent’s home littoral and in the later stages of a conflict when an enemy A2AD system is significantly degraded. The DDG 1000 had few direct threats when first conceived and if employed close to shore as demanded by the range of its main battery guns, any gain in stealth from the ship’s tumblehome hull form will be offset by the danger of visual detection. The ship does have some formidable strike and defensive capabilities through its vertical launch system (VLS) mounted missiles and AN-SPY-3 radar system. It remains to be seen, however, if those capabilities justify deploying the ship on the front lines at the outset of a high-end conflict. The DDG 1000 is dominated by the AGS that can only be employed at the present time against land-based targets.

Armored cruiser USS Brooklyn, a US example
of late the 19th century tumblehome hull

     The Daily Beast article and others have discussed questions of the ship’s tumblehome (inward curving) hull form and stability in rough seas. The tumblehome hull was a familiar feature of many warships at the end of the 19^th and the beginning of the 20^th century. French,  Russian, and some American warship designers embraced it as a way of creating greater freeboard (height from water line to deck), better sea-keeping, and from these together, improved gunnery. The tumblehome hull's inward curve from the waterline to the main deck causes a reduction in reserve buoyancy, the amount of the ship outside of the water. Freeboard is the physical factor that allows steel ships to remain afloat. A small reduction in reserve buoyancy, especially if received off the center

French battleship Bouvet sinks during 1915 Dardanelles attack

line of the ship in the form of flooding from battle damage or fire-fighting efforts could cause a sudden loss of stability and rapid sinking. The ship's reliance on automated damage control systems, combined with reduced reserve buoyancy could be a problem in the case of significant flooding. Warship designers began to view the tumblehome hull as suspect after the Russo-Japanese War when several Russian warships with that feature capsized and sank quickly after only moderate damage. The feature was discarded wholesale after the First World War saw significant casualties in French warships with the unconventional hull form. The Bouvet (shown in above photo) struck a small mine (176 lbs) and sank in less than two minutes.

USS Lexington (CV 2) using her turbo-electric
engineering plant to provide power to
Tacoma, WA in 1929

     Despite these possible problems with its main armament and hull form, the DDG 1000 represents a return to a number of positive features and notable firsts worth further exploitation and development. The ship's electric drive system is the first for a U.S. “capital” warship since turbo-electric propulsion systems were installed on the U.S. aircraft carriers Lexington and Saratoga in the late 1920’s. These units were so capable that Lexington's powerplant was able to provide 25% the city of Tacoma, Washington's electricity in 1929/1930 after extreme drought conditions made hydroelectric sources in area useless. Turbo-electric power proved to be a very fuel efficient system and extremely robust in combat. Both ships sustained significant damage  during World War 2, and although Lexington was sunk at the Battle of the Coral Sea in May 1942, the ship's turbo-electric drive system remained operational until spreading fires made the ship untenable. The DDG 1000’s similarly large electric power plant is the first step toward fielding directed energy weapons at sea. These include electromagnetic rail guns with greatly increased range that may replace the AGS currently fitted. The AN-SPY 3 radar represents a significant advance in detection, and air and missile defense capabilities, especially in congested littoral areas. The 155mm gun still has a part to play. It has surface warfare potential if converted to a dual purpose land/surface attack weapon. While perhaps an interim step in the direction of a rail gun, the AGS could also play a useful anti-surface role. The main battery of the DDG 1000 could quickly smother an enemy warship in a barrage of 155mm projectiles from 24nm to 60+ nm. Defense against artillery and mortar shells is possible, as demonstrated by the U.S. Centurion Gun System, but it is not a capability currently found on the warships of potential aggressors. Experience from the employment of the AGS as a surface gunnery weapon is again also a step toward use of a railgun as anti-surface weapon with estimated ranges between 110 and 220nm.

Advanced Gun System
Assembly

     Potential operational and damage control issues aside, the DDG 1000 represents a good investment in future capability. It could be altered enough to make the ship a viable addition to a post-Post-Unipolar U.S. fleet. Enabling the 155mm AGS as a surface weapon would expand U.S. anti surface warfare capabilities and force opponents to spend money to undertake defensive measures against artillery shells. One or more of the ships could be altered (if stability conditions permit) as prototype cruiser platforms optimized for anti-air/missile defense by removing one AGS and substituting greater missile armament in its place. The ship’s stability after receiving damage remains a concern, especially as it relies on an automated damage control system to provide much of the immediate response to the effects of weapon strikes. The composite material deckhouse of the first 2 units, as opposed to the steel version on the third and final unit of the class represents an additional vulnerability. All such shortcomings, however, may be more effectively addressed if they are acknowledged as such. No warship is perfect and each represents a series of choices. The choices available to designers in the late 1990s are different from those that must be considered in the present. The DDG 1000 class represents a welcome addition to the fleet in that the technologies and capabilities they possess will likely be core components of the fleet of 25 years hence. Together they might form a valuable “squadron of evolution” for the 21^st century and be useful elements in exercises and wargames.

     The famous naval author Joseph Conrad described the actions of an isolated warship conducting naval bombardment against unseen targets at the beginning of his most famous novel The Heart of Darkness. In it, his narrator Marlowe describes a French cruiser shelling unseen enemies ashore as follows:

“Once, I remember, we came upon a man-of-war anchored off the coast. There wasn't even a shed there, and she was shelling the bush. It appears the French had one of their wars going on thereabouts. Her ensign dropped limp like a rag; the muzzles of the long six-inch guns stuck out all over the low hull; the greasy, slimy swell swung her up lazily and let her down, swaying her thin masts. In the empty immensity of earth, sky, and water, there she was, incomprehensible, firing into a continent. Pop, would go one of the six-inch guns; a small flame would dart and vanish, a little white smoke would disappear, a tiny projectile would give a feeble screech—and nothing happened. Nothing could happen. There was a touch of insanity in the proceeding, a sense of lugubrious drollery in the sight; and it was not dissipated by somebody on board assuring me earnestly there was a camp of natives—he called them enemies!—hidden out of sight somewhere."

The original design of the DDG 1000 may have evoked a similar image of unimpeded naval surface fire support, but the unrestricted sea control that Conrad’s imagery conjures up is no longer a reality in the second decade of the 21^st century. While perhaps not designed for such conditions, the DDG 1000 still has a significant role to play in the present as both a technology demonstrator and as a surface warship. The specter of its guns may yet haunt future opponents and it’s all-electric heart power future weapons of greater capability and effectiveness.

Side view of Zumwalt