title: The Minimum Viable Navy
content_type: article
published: 2023-05-22T00:00:00
source_url: https://austinvernon.site/blog/navyneeds.html
word_count: 7922
The Navy Conundrum
Every military branch is preparing to face China in the Western Pacific. The directives for the Air Force and Army are relatively clear. The Air Force needs to keep its bases running and its planes from getting destroyed on the ground. Some combination of dispersal bases, hardening, and active defenses is the answer. The Army needs better missile defenses (it provides ground-based air defense at Air Force bases) and short-range air defenses to counter drones.
The Navy is different. Uncertainty is much higher, and the service is muddling through, mostly maintaining the status quo. Many of its recent shipbuilding programs have been disasters (Ford, Zumwalt, LCS). Part of the issue is that there hasn't been a significant naval battle for 80 years, and there have been no real challenges to the US Navy until recently. Armies and Air Forces have had Korea, Vietnam, the Israeli-Arab wars, and two wars in Iraq to showcase changes in warfare. The advances in naval warfare have been theoretical outside of a few engagements clustered in the 1980s where anti-ship missiles tussled with lower-tier ships.
Instead of trying to speculate on what would be the perfect Navy, I'm going to guess how we might rapidly augment a few capabilities that would be in high demand during a conflict with China. I've mentioned many of these in other posts but will go into more detail here.
Setting the Strategic Framework
A recently published war game simulating a Chinese invasion of Taiwan provided food for thought. War games aren't real life, but that doesn't mean we can't learn from them, especially one that alters assumptions to see the direction and magnitude of change. War games are like setting a point spread for a football game. They guess a median outcome without addressing the messy tail events that happen during an event. Some notable opinons:
Improve Land-Based Airpower
Some of the most favorable changes for the US were the ability to use all of Japan's airports and the hardening of existing bases from missile attacks. Fewer planes died on the ground, and tactical airpower helped whittle down Chinese shipping, leaving the invasion force without support. Base hardening is expensive, and the Air Force has focused on the most critical projects like standing up dispersal fields, hardening fuel infrastructure, and building shelters for maintenance equipment. Pricier upgrades like hardened aircraft shelters aren't a priority. They prefer to buy new planes or work on their next-generation fighter.
Hardened aircraft shelters started simple and cheap during Vietnam as emergency protection from rockets. They have grown into sophisticated buildings with extensive features. But basic will come back in style if war becomes imminent. The construction operation in Vietnam could complete almost a shelter a day at its peak, with each coming in at $200,000 in 2023 dollars.
Anti-ship Missiles Hurt China More
One of the most contentious assumptions is how vulnerable ships are to anti-ship missiles. The more vulnerable ships were, the worse China performed. US naval forces can stay relatively far away from China. But China has to constantly have ships crossing the Taiwan Strait to support its invasion. There is always the possibility that China's missile defenses are much better, but typically we underestimate the capabilities of open democracies and overestimate totalitarian regimes. The US Navy surface fleet will cease to be relevant if there is a gap and it doesn't learn fast.
Taiwan's Army Has to Fight
Taiwan did not stop an initial landing of Chinese troops, even with many varying assumptions. The Taiwan Strait is only 100-200 km across. Time is short and Chinese ships are numerous during an invasion. The outcome probably looks more like Ukraine losing Crimea if the Taiwanese Army collapses. The US will move on with a minor response. We can only deploy our forces and influence the fight if the Taiwanese fight hard.
The Japan Question
Japan's participation is critical to any US defense of Taiwan. A dozen potential airfields are available on Okinawa and other Japanese islands - the closest is only 120 km from Taiwan. Naval aircraft can fly from these land bases if carriers aren't available. There are also bases in the Philippines, but they are not as well positioned as the Japanese airfields. Whether Japan will fight is an important question.
Japan may not have a choice. Many of China's military thought leaders favor a first strike on US bases in the region, many of which are in Japan. You can't discount Chinese landings on the lightly populated islands closest to Taiwan.
Taiwan keeps China bottled up and out of the wider Pacific. Japan would be extremely isolated and at the mercy of China if Taiwan fell. They remember nearly starving due to US submarines and mines in World War II. Japan's best chance to maintain their current level of autonomy is to fight with the US to defend Taiwan and themselves. Their rapidly increasing military budget supports this line of reasoning.
The Navy's Role in East Asia
The Navy's minimum role collapses and simplifies when we combine the strategic factors. Carriers get all the attention, but the Navy can rely on land-based air cover from its planes and the Air Force when the battlefield is a confined space like Taiwan. Supply lines to these bases and our allies are still critical. Several objectives emerge:
Maintain supply lines to island airfields
Tactical aircraft need fuel, parts, bombs, and missiles.
Reopen sea lanes to Eastern Taiwan
Taiwan will wither and starve without deliveries of food and ammunition.
Improve submarine access to Chinese waters
US Navy submarines are an alternative to missiles for putting pressure on Chinese shipping.
How the US Navy Can Achieve These Objectives
The two primary obstacles to these objectives are mines and diesel-electric submarines.
Surface vessels are less of a concern to supply lines. The Chinese Navy often deploys ships on the east side of Taiwan during exercises, but they are more exposed, and the ocean depth is favorable for the US. Attack submarines, bombers, fighters, and surface vessels are all available to attack.
US Supply lines can operate under land-based air cover and missile defense along the Ryukyu Islands. The best ways for the Chinese to disrupt these supply chains are mines and submarines.
The Ryukyu Islands are Unsinkable Aircraft Carriers* Source
The US will only suffer a shortage of tactical airpower if we lose our carriers AND can't access Japanese airfields AND lose access to basing rights in the Philippines AND still want to fight. If Taiwan only spends 2% of its GDP on its military while Japan and the Philippines want to be "neutral," why should the US fight for them from a terrible strategic position? We might, but we can always contain China's further expansion from the second island chain, where our advantage is still decisive.
Mines and submarines!
Minesweepers
China might have 100,000 naval mines they can deploy from fishing boats, submarines, ships, or aircraft. These mines could keep US ships and submarines from operating in the shallow waters surrounding Taiwan, prevent the resupply of Taiwanese armed forces, and hinder US operations by covertly mining key points around Okinawa or Guam. Mines caused problems for the US Navy in Korea and the First Gulf War. The Chinese hope for similar success if a war erupts.
The US Navy has eight aging minesweepers. Four are in Japan, vulnerable to a Chinese first strike. The other four are in the Persian Gulf. It also has a few tired helicopters that pull sleds. The Littoral Combat Ship (LCS) was supposed to take over from these aging platforms, but it has been a complete failure.
There are two ways to counter mines - sweeping or hunting. Mine sweeping is fast but imprecise and usually involves triggering mines by imitating ships. It does not locate individual mines, and some can be left. Hunting mines means deliberately searching for every mine and destroying them. It is thorough but painfully slow. Advances in mines hurt the effectiveness of sweeping because the mines don't fall for simple decoy signals meant to trigger them. Some mines can attack specific classes of ships based on their unique signature. Many mines are now bottom-dwelling to make detection challenging and prevent sweepers from breaking their moors with heavy lines. Most of the Navy's recent focus has been on mine hunting due to the challenges of sweeping. But sweeping might come back in fashion if tens of thousands of mines cover every key chokepoint.
Minesweepers are made out of wood and fiberglass when there is time to spare. These materials make the ship less likely to trigger mines. But there is a history of using steel or converting existing ships (civilian or military) to minesweepers in emergencies. There are several features these ships might have:
Sonar to Find Mines
Most minesweepers have active sonar arrays to find potential mines. There are low-resolution modes for broad searches and high-resolution modes for investigating potential mines. The Navy might have to adapt less capable off-the-shelf sonar and put those arrays on whatever ships they can scrap together.
Charges to Destroy Mines
A brute force option might be launching depth charges at anything that looks like a mine on wide-view sonar rather than confirming with narrow-band sonar, UUVs, or divers.
Better Mine Triggering Methods
It would be ideal if new decoys could simulate ship sounds and magnetic signatures well enough to trigger mines.
Underwater Micro Drones
Some proposals envision launching small unmanned underwater vehicles from motherships to seek out mines and eliminate them - essentially underwater loitering munitions. These are one of the few technologies that might help US submarines fight in the shallows deep in Chinese territory.
Minesweeping capability will be critical for supplying forward bases, keeping Taiwan from starving, and gaining entry to the Taiwan Strait later in the conflict. The fastest capabilities will be converting existing vessels by outfitting them with sonar and simple ways to launch charges at suspected mines. Micro UUVs and synthetic mine triggers should be crash R+D programs since they could dramatically improve effectiveness.
The People's Liberation Army Navy (PLAN) has numerous short-range diesel-electric submarines that excel at fighting in shallow waters. They are quiet and hard to find when they operate in battery mode. Many US sonars work better in deep water, compounding the diesel sub advantage. Their slow electric speed (<3 knots to avoid running down the battery) is a disadvantage but matters less when operating in shallow choke points. Many of these subs will be laying mines, making it even more critical to neutralize them. Finding the submarines is the hard part. The US may not have air supremacy, so the answer can't be P-8 patrol planes dropping buoys at every likely hiding place. There are a few options:
More Advanced Listening Network
The US tracked Russian nuclear submarines during the Cold War with a network of sensors in the Deep Sound Channel that transports noises for hundreds or thousands of miles. Most waters in East Asia are too shallow for this layer to exist. A network in East Asia will need more nodes or different technology to work effectively.
China has also built listening networks to counter US submarines.
Underwater Seagliders
Expendable Drone Aircraft
Another speculative option is putting sensors like magnetic anomaly detectors (MAD) on small, inexpensive flying drones. You might be able to buy hundreds of these for the cost of one anti-submarine warfare (ASW) helicopter, increasing the coverage area.
ASW Patrol Boats
There won't be time to build anti-submarine warfare powerhouses like a Perry-class frigate or Spruance-class destroyer. And the current fleet has no dedicated ASW ship. There will be a need for boats capable of escorting carrier battle groups and convoys. The more desperate the timeline, the more ramshackle solutions will be. Grafting on older sonar arrays and torpedo racks is probably the bare minimum.
China's submarines hope to disrupt US Navy access to the waters around China and Taiwan. The US will have to locate them. A new listening network optimized for East Asia is the best and most reliable option, while drone capabilities might supplement them as technology improves.
Turning the Tables
Our three objectives get increasingly challenging. It is easier to build listening networks or clear harbors of mines in the Ryukyu Islands than in Taiwan. Even harder is locating submarines and eliminating mines in enemy territory. But operating closer to China opens opportunities for the Navy to threaten the Chinese invasion independent of carriers, airfields, Air Force bombers, or long-range missiles.
Offensive and Defensive Mines
Anti-ship mines could be as dangerous (if not more) for the People's Liberation Army as the US and its allies. Taiwan has few beaches and ports suitable for amphibious invasion, making Chinese movements predictable. Hundreds of kilometers of shallow water that are ideal for mines surround China. They are a chaos-inducing weapon because they could delay or destroy Chinese ships, allowing Taiwan to mobilize its military. Mines could also be a way for the US to support Taiwan without committing to a full intervention.
Shallow water!* Source
Unfortunately, the US has neglected mines until the last few years. Its inventory (~10,000 mines?) is inadequate and new models are not fully operational. There is also a minelaying capacity issue. Nuclear attack submarines can only carry 20-50 mines. B-1 and B-52 bombers can carry up to 80 smaller mines but may be too valuable and vulnerable to sortie on minelaying. B-2 stealth bombers do not even train for mine-laying missions. Rapid deployment matters because minefields often need thousands of mines to be effective.
There are a few initiatives to correct these issues:
Quickstrike Mines
The Navy recently upgraded its Quickstrike air-launched mine family with modern sensors. These shallow-water mines are conventional bombs with fuses swapped for the mine sensors. The appeal of the Quickstrike mines is that they benefit from air-dropped bomb economies of scale and scope. The cost is low, and manufacturing can ramp quickly. JDAM guidance packages allow aircraft to launch mines from 80 kilometers away. Previously, aircraft had to fly low and slow over the minefield, making them easy targets.
The Air Force may not want to risk its bombers to lay mines, but it might be willing to risk C-130 cargo planes. The Rapid Dragon program is giving them the ability to drop JDAM-equipped bombs. There are enough C-130s to lay entire minefields in one mission, helping to justify the aircraft package of fighters and electronic warfare aircraft required to get the cargo aircraft close enough to drop the mines. There is still a limit to where the Navy and Air Force can realistically deploy these weapons.
Clandestine Delivered Mine
Submarines can deploy mines closer to enemy shores and ports than aircraft. The Navy is upgrading its obsolete submarine mines with the CDM. There are no details about its abilities or operational status.
Hammerhead Mine
Increasing the range that a mine can kill a ship or sub reduces how many mines the Navy needs to lay. The Hammerhead Mine is a system that fires a torpedo at targets, extending its range from meters to kilometers. They would help alleviate the submarine minelaying constraint. The program could reach operational status within the next few years, but rumors suggest production is only thirty units per year. That is not enough to move the needle!
Programmable Mines
Mines used to be indiscriminate. Now they can decipher what kind of ship they are attacking. The next step is to lay them in a dormant state and only activate them at the start of hostilities. Fewer platforms can place mines before a conflict erupts. The Navy has shown interest in this capability, but no known programs are pursuing it.
Mines hold incredible potential for the US Navy, but every initiative needs a 10x multiplier.
Unleashing US Attack Submarines
The Navy needs previously discussed improvements to minesweeping and submarine detection to reduce the risk of operating subs in Chinese waters. Better weapons can also help submarine survivability. The harpoon missile and Mk-48 torpedos are undergoing incremental upgrades. Torpedos can always be quieter at the start (to avoid giving away the sub's position), faster in the final sprint toward the target, and better at targeting.