History’s first duel between ironclad warships during the American Civil War ushered in the beginning of a new era of naval warfare
In case naval strategists and warship designers didn’t notice the significance, the shooting down of an Iranian drone in the Strait of Hormuz on 18 July 2019 by the USS Boxer was actually the beginning of a new naval epoch, comparable in magnitude to the Battle of Ironclads in 1862. The historic engagement between the CSS Virginia and the USS Monitor near Chesapeake Bay was the inaugural use of warships in battle with steel armoured hulls and it proved pivotal. It was also the first time an armoured rotating turret was used to mount heavy weapons.
Preceding battle, the Confederate ironclad CSS Virginia engaged conventional wooden-hulled Union ships, sinking two and wreaking havoc among the other three. Hot shot (cannonballs heated red hot) was used by the Confederate ship to start fires on their ligneous opponents. One of the Union ships, USS Congress, caught fire and her magazine exploded causing her to sink with the loss of most of her crew. Union canon fire was largely ineffective against CSS Virginia’s ship armour, although they suffered some battle damage and several casualties.
The naval battle of Ironclads in 1862 was hugely significant as it influenced the design of warships for the next 157 years. Rotating gun turrets and ship armour became a staple of naval warfare that persists today.
Naval Drone Warfare
While the USS Boxer’s action to shoot down a threatening drone is seemingly innocuous, this is only the case when the incident is viewed through a contemporary lens. So, it’s easy to overlook this seminal event in terms of its place as a strategic marker in naval warfare history. Fast forward ten or twenty years into the future and consider what drone threats might be like then. If the development of other forms of weapon systems are anything to go by, such as aircraft, warships or tanks, then drone threats are on the cusp of exponential capability growth.
Consider swarms of armed, neurally networked anti-ship drones attacking a warship; these might include literally hundreds of fast moving, low flying or sea skimming variants. Subsurface drone teams could also coordinate with aerial and surface drones to create multiple dilemmas for Principle Warfare Officers attempting to coordinate warship defences.
What is also noteworthy about USS Boxer’s action is the Iranian drone was not destroyed by a weapon system integrated as part of the U.S. warship. A U.S. Marine Corps anti-drone combat vehicle parked on the flight deck achieved the drone kill with a signal-jammer. This illustrates just how unprepared extant warship designs and weapon system configurations are for future drone risks of the type I describe. Particularly, noting drones appear set to become immune to military jammers. So, the only sure-fire way to kill a drone is going to be via violent kinetics.
The hazard trajectory of armed drones is now apparent in terms of future naval combat. So the implications for naval architecture are of a magnitude to justify a new class of warship and the reintroduction of some naval weapon systems long considered obsolete.
Anti-ship drones may be armed with a variety of weapons; missiles with blast, fragmentation and shaped-charge warheads. Kamikaze style drones packed with high-explosive or highly corrosive acid may also feature. It’s plausible that torpedo bomber drones might be developed to deliver miniaturised torpedoes. Smaller net explosives content in drone weapons will be compensated for with next-generation high-explosives that generate greater detonation velocities and blast pressures than extant military grade explosives. Worst case, drones will be equipped with chemical, biological and radiological agents to incapacitate a warship’s crew.
Dronenaught Class Warships
The Dreadnaught immediately made all preceding battleships obsolete.
Dreadnaughts were the principal variant of battleship in the early 20th Century. These heavy battleships employed multi-barrel rotating gun turrets from bow to stern and were protected with thick belt armour. Battleships were usually capital ships with longer and wider hulls to provide sufficient displacement for the extra weight of armour, gun turrets and ammunition. Lighter classes were designated battlecruisers, which featured less armour with faster, sleeker hulls enabling superior tactical diameter (measure of a ships manoeuvrability).
Battleship and battlecruiser class ships were superseded in the age of guided anti-ship weapons and pre-eminence of Fleet Aircraft Carriers. Agile Frigates and Destroyers became the preferred warship design to protect the Carriers.
Noting naval attack drones may be signal jammer resistant, and could attack in huge numbers, a heavy weight of sustained, radar-controlled gunfire may provide the most optimal defence for future warships. Hence, it may be time for warship designers to dust-off old architectural plans for battleships and battlecruisers. Reconsidering battleship designs in-light of future, close-in autonomous naval threats that require massive volumes of firepower may be time well spent; warships bristling with barrels may be needed once again. Therefore, extra combat weight of anti-drone weaponry lends itself to development of Dronenaught Class Warships.
Air Warfare Destroyers (AWD) may provide an interim drone warfare solution. But without upgrade, they could become obsolete before the planned life-of-type expiry. Extant AWD weapon and fire control systems are probably not fully optimised for massed smart drone attacks occurring simultaneously from above, on and under the sea.
Directed energy weapons for warships already exist, so they will also be a key inclusion in gunnage integrated into Dronenaught Class battleships or battlecruisers.
Anti-drone laser systems are operational in the U.S. Navy and provide precision anti-drone effects at range. But they are reliant on a power generation system that during multiple drone-wave assaults could fail or overheat while under heavy power demand of sustained laser firings. Banks of complex laser systems would be required to provide enough protection from obstinate drone swarms attempting to evade or confuse warship defences. I therefore propose a mix of conventional multi-barrel, rapid fire naval gun systems and directed energy weapons to provide counter-drone mission redundancy and complimentary weapon system effects.
Dronenaught battleships will require fully automated weapons: two or three triple barrel 5 inch gun turrets, both fore and aft for axial and broadside airburst fires and rows of quad-barrel 40mm Pom-Pom Guns for raking flak effects. All in addition to an increased ships equipage of Phalanx close-in-weapons-system 20mm Gatling Guns for terminal defence.
Dedicated anti-drone missile systems will also be desirable to increase combat reach of Dronenaughts beyond naval gun ranges. Depth charges, miniaturised homing-torpedoes and paravanes could be employed for undersea drone protection. Concentric circles of defence-in-depth by layered fires, including under-ship weapon effects, will deplete drone swarms on attack vectors from numerous azimuths, altitudes and ocean depths. To save weight and stowage space on board the new warships, cased-telescoped ammunition will be crucial to sustain firepower for multiple counter-drone engagements. Hence, considerable extra weight of gunnage and ammunition will require a larger class of warship than a Frigate to be feasible.
With every Dronenaught warship essentially a huge phalanx system and an overwhelming number of incoming targets, Principal Warfare Officers will require augmentation via artificial intelligence fire control systems to prioritise and engage robotic threats.
Force Structure Shocks
‘You can’t lose your defences before you have alternatives ready, no question.’ – Jennifer Mather
Like any emerging technology of war, the growth path will be iterative so it may be some time yet before a Dronenaught type of warship is required at sea. Hence, capability upgrades on existing warships will be critical in the short-to-medium term. These could include kinetic and non-kinetic naval weapons designed to disrupt drone threats. But long-term, bespoke classes of drone defensive and offensive warships may emerge. Dronecraft Carriers, inspired by retired Escort Carrier designs, may also feature with embarked drone squadrons. Drones could be integrated with all-round defence from aerial, surface and undersea threats. Moreover, rapid 3D printing of drones could occur aboard Drone Carriers to replace combat losses at sea.
Dronecraft Carriers would need protection from ‘like’ threats, hence Dronenaught class battleships and battlecruisers might become the norm in future. Frigate designs of today could become obsolete, like wooden-hulled ships did, in the next evolution of naval warfare.
This emerging seismic shift in the character of maritime combat has serious implications for the Australian Defence Force’s SEA 5000 Future Frigates program. The program is part of a national warship-building effort charged with acquiring next-generation warships to replace ageing ANZAC Class Frigates. So perhaps a reassessment of SEA 5000 capability requirements may be in order, as the technology situation and hazard outlook has materially changed. An evolving future threat picture could translate to strategic program risk if warship requirements are not revised to account for the Ironclad-like inflection point the world just witnessed in the Middle East.
About the Author: Greg Rowlands, a retired infantry Lieutenant Colonel, served over 27 years in the Australian Army. He holds four degrees and is a graduate of both Command & Staff College and the Capability & Technology Management College. He has served as a company commander during amphibious operations in Australia and Solomon Islands. Greg has published extensively on drone defence concepts, including emerging technology trends and shocks to inform Defence modernisation. You can find him on Twitter @glrowlands1.
The outcome of the battle was indecisive with both ironclad ships successfully disengaging from the fight.
Kamikaze drones will target critical areas of a warship with a degree of relentless precision their namesakes could not have accomplished in WWII: Bridge, radar systems and communications infrastructure.
Mini torpedoes could also be fired by subsurface and surface attack drones, aiming for the stern to disable propulsion systems. Inventive weapons might deploy wire in a ships path designed to befoul the ships screws.
If chemical, biological and radiological (CBR) weapons (dirty bombs) are released by hostile drones it would be a major escalation and a breach of Geneva Conventions. So, while it’s unlikely a state actor would employ CBR weapons, it must be accounted for in drone counter-measure calculus. Particularly if terrorist groups obtain CBR drone systems. Hence, the likely operational need for an impenetrable layered shield of hot lead, airburst munitions, undersea high-explosives, anti-drone missiles, sentry drones and precision laser systems.
The Royal Australian Navy might also consider potential recruiting and retention dividends of battleships and battlecruisers being brought back to the fleet. Benign warship class names, such as ‘Frigates’ are, arguably, uninspiring to young Australians considering exciting new career options. There could also be a greater naval ‘deterrence’ effect that enhances national security if more formidable warship classes are acquired.
A new class of anti-drone warship but based on battleship and battlecruiser pre-eminence in warship pecking order. Naught means ‘for no effect’, hence ‘Dronenaught’ means that hostile drone attacks will be neutralised.
AWD could potentially be re-engineered as a Drone Warfare Destroyer (DWD) interim capability solution.
To maximise the distribution of gunfire, fore gun turrets are echeloned to starboard and aft gun turrets are echeloned to port. Gun turret position offsetting will also provide counterbalance and greater stability at sea.
Rail guns may be ineffective against drone swarms. Hypersonic kinetic energy projectiles would pass right through the swarm causing limited damage. Hence, several multi-barrel, echeloned gun turrets firing airburst munitions would provide a superior effect against large numbers of naval drones in echeloned attack formations.
Multi-gun decks like Spanish Galleons of old, only gun deck weapons are fully automated and retractable.
A high number of weapon systems will increase the warships radar cross-section. Therefore, where possible, retractable gun sponsons should be engineered. Radar reducing superstructure design, radar absorbent technologies, heat mitigation and advanced acoustic masking will also be essential requirements. As reducing the warships detectable signatures will be a critical aspect necessary for Dronenaught class warships to pass feasibility testing: https://groundedcuriosity.com/when-radio-silence-is-not-enough-signature-suppression-the-fight-for-surprise/
Layered naval gunfire and missile effects might also be an option to provide anti-ship ballistic and hypersonic missile defence. With sufficient missile early warning, several Dronenaughts could coordinate via artificial intelligence fire control networks to create a crossfire above targeted warships. A massive volume of fire from several battleships or cruisers may destroy incoming anti-ship missiles before they can hit their intended targets.
It would be like the Battle of Midway or Guadalcanal of WWII all over again; only attacking enemy forces have physically smaller, far more numerous and autonomous combat systems. They may also have far superior C2.
Drone Carrier warships would differ from aircraft carriers of today as they would employ both aerial, surface and subsurface combat squadrons, only these drone squadrons will all be autonomous and or semi-autonomous.
New naval trade structures will be required i.e. Able Seaman Drone Technician (ABDT).
Drone Carriers, Battleships and Battlecruisers could also be employed to support amphibious landing operations. Naval drones could deploy from the carrier to provide close tactical support to land forces going ashore.Concentrated naval gunfire support from Dronenaughts would protect landing craft and deploying Army units if they were attacked.
Frigates with their paucity of naval guns; a single 5-inch gun turret and a handful of Phalanx systems will be vulnerable to drone swarm threats. Current naval missile systems are optimised for anti-aircraft or anti-ship roles. Frigates also will not be capable of stowing enough ammunition to be survivable in naval drone warfare.