Supporting the Fight Ashore (Part II)
As shown in Part I, the USN has a serious deficiency in providing Naval Surface Fire Support (NSFS). The only fielded NSFS weapons, both 5” guns and the Advanced Gun System (AGS) on cruisers and destroyers, do not meet USMC range thresholds, have questionable ability to sustain NSFS during high intensity operations, and are ill-suited to engaging moving or hardened targets. As the USN and USMC pursue their new Littoral Operations in a Contested Environment (LOCE) concept, NSFS could become even more important.
Another issue with NSFS weapons on current USN ships is that all the cruisers and destroyers are expensive, multi-role platforms. NSFS missions pull them away from area-air defense, high value unit escort, ballistic missile defense, undersea warfare and other priorities. The NSFS mission puts these valuable multi-role assets in a more dangerous position, forced into shallower water and close to shore, to utilize their limited capability and quantity weapons. The expected tempo of operations in NSFS would also likely result in the firing platform being detected, increasing its risk. This results in multiple cruisers and destroyers being needed, as well as underway replenishment vessels to reload them and get them back on the gun-line. In the Falklands Island War multiple British warships were crippled and sunk by basic iron bombs while supporting the landing forces, and one struck by one of only two Coastal Defense Cruise missiles fired. Most of the British ships did not survive their damage, and the remainder had to withdraw from the scene of action. With a scarcity of warships available to risk in close, this is a serious concern for a naval planner when deciding what to move into a riskier position to support forces ashore.
Some potential options to improve this situation are Hypervelocity Projectiles (HVP) and the Army Tactical Missile System (ATACMs). If fielded on ships, they may provide the ability to meet the range and lethality thresholds, but the ability to sustain fires will still be an issue due to limited magazine capacity, whether VLS cells for ATACMs or gun ammunition stowage for HVP. So, the range and lethality requirements might be met, but not sustained. ATACMs, in particular, could not be reloaded at sea. Is there a better way?
Bringing the fight in close
If cruisers and destroyers aren’t the best option, what is? The first thought of many when discussing an NSFS ship is a battleship, either a reactivated IOWA or a new class. However, as indicated in Part I and other articles, these do not seem to be feasible, especially in the short term. A solution is needed sooner, not later, to help enable the LOCE concept and free multi-mission ships to perform their primary duties. The USN already has a modular high speed combat vessel designed to operate in the littorals, the Littoral Combat Ship (LCS). An NSFS support module could be developed for the LCS. The USMC High Mobility Artillery Rocker System (HIMARS) launcher weighs in at 12 tons, the same as a fully loaded MH-60 helicopter. Subtract the truck portions and perhaps two HIMARS modules could be placed on the LCS’s flight deck, with reloads of shorter range rockets or longer range ATACMs stored in the mission area and reloaded as needed. The INDEPENDENCE variant might be particularly suited for this with its much larger flight deck. Another option might be to mount ATACMs VLS cells forward of the SeaRAM mount, keeping the flight deck free. The concept of the LCS as a rocket platform has already been discussed at CNO and Commandant level.
The NSFS module for LCS would capitalize on the LCS design for littoral missions, allow the ship to contribute to an additional mission set, and free up cruisers and destroyers while providing a relatively large number of hulls to perform the mission. The ATACMs anti-ship capability would also provide the LCS with a long-range punch for naval engagements. However, the LCS would not be able to carry many rockets and thus would suffer from the same fire sustainment issues as other options. The NSFS rocket modules would have to be limited in number of placements to allow vertical replenishment of reloads, or the ship’s sustainment would be further limited. Fuel is also a concern. While LCS is very fast, using this capability is similar to flying a jet on after-burners. The speed is gained at great expense in fuel. This could impact its ability to remain on station. Finally, there is a survivability concern. LCS was designed to a much lower ship survivability requirement than cruisers and destroyers. The NSFS mission would result in a higher exposure to danger with reduced ability to cope with damage.
Another idea would be to take a large commercial hull and equip it with weapons needed to support forces ashore. Large ships are inherently resilient. In July of 1987, the USN escorts of SS Bridgeton had it assume the lead through a minefield, knowing the Bridgeton was far more capable of surviving mine strikes than the much smaller warships. Bridgeton struck a mine, had 4 of 31 compartments flooded, but kept on steaming with the warships in its wake. Contrast this experience with that of the USS SAMUEL B. ROBERTS, which was crippled by a single mine strike and had to fight for its life with heroic damage control efforts. The sheer volume of Bridgeton, and other larger vessels, allow them space to absorb damage. The Exxon Valdez grounding punctured every tank along the centerline of the ship, as well as most of the starboard side. When freed from grounding, she was towed to dry-dock despite this massive underwater damage. Nevertheless, the “Tanker War” between Iran and Iraq provides sobering lessons in ship vulnerability as even the world’s largest oil tanker was burned out and written off as a total loss after being struck by Exocet missiles. Oil tankers hit by suicide boats off of Yemen also show the vulnerability of large, thinly crewed vessels transporting flammable material.
However, these were ships loaded with flammable oil. Had this not been present, or tanks filled with water instead, the ships would have been far less vulnerable. An Naval Postgraduate School thesis detailed an analysis of missile damage, and its projections showed that more than four Exocet equivalent missiles would be needed to cripple a 7,000 ton ship. It also concluded that it takes two to three times as many missiles to sink a ship as to put it out of action. While the study did not cover a 70,000 ton vessel, one can imagine how many missiles could be absorbed within its sheer volume, or that of one truly super-tanker sized. Thus, a vessel like this would be far more likely to survive in close to a hostile shoreline than existing warships, especially if it was not carrying vast amounts of oil but inert, nonflammable materials instead, and it was built to standards assuming it would take hits, unlike the standards for civilian vessels.
The Israeli’s have already demonstrated firing the Long-Range Artillery (LORA) maneuvering ballistic missile from the deck of a cargo vessel. This standard-shipping containerized options allows many platforms to be used. The shipboard variant has 16 launch tubes and 16 reloads, providing 32 total weapons able to strike targets over 250 miles away.
Now, let us imagine converting or building the ship to make it more effective. Take a standard large cargo ship or tanker design, perhaps a hull similar to what is used for the USNS LEWIS B PULLER (T-ESB-3), an existing 80,000 ton mobile landing platform. Instead of the larger, empty center section, put armored cylinders around NSFS weapons systems. Instead of the “all or nothing” armored citadel of historic US battleships, this vessel would have multiple barbette like armored cylinders, each enclosing an independent weapon system. Armor, taken from armored vehicle designs, would protect each cylinder. These cylinders would be well inside the skin of the ship, and separated from each other. Redundant and armored power, data and water connections would run between the cylinders, reducing the risk of a hit severing vital systems. The ship’s large volume would act as spaced armor for these armored cylinders. In effect, the cylinders and vital spaces would be like independent armored vehicles, and the rest of the ship’s volume a honeycomb around it to absorb damage. If a missile got past close in weapon system defenses, weight and space permitting, thin layers of armor or water-filled areas could be layered to defeat a missile’s warhead before it reached the cylinders. If it did, and the armored cylinder was breached, there could be blow-out panels similar to what is used on the Abrams tank to vent the explosion up and away from the ship. While one cylinder would be destroyed, the rest would remain. To keep costs down, defensive weapons would be minimal and off-the shelf. An 80,000 ton vessel could fit multiple cylinders (based on dimensions needed), and a 200,000 ton super tanker sized one even more. Crew requirements for large civilian ships are relatively small, and most of the ship would be a honeycomb around the cylinders, so the question would be manning and maintenance of the weapons cylinders more than the ship.
What weapons could be put in these cylinders? Anything from Part I of this article. AGS could fire HVP, Excalibur or LRLAP rounds. Standard 5” 62 caliber would ease logistics (common systems). The large cylinders could contain more ammo stowage than what is available for each turret on a conventional warship. Railguns would be useful if they come online with sufficient power production. MLRS rockets or ATACMS rockets could be housed in vertical launch cells or simply launch turrets bolted to a ship’s deck and, perhaps most importantly, are reloadable at sea. The deck space and stability of a large ship could support reloads that cannot currently occur on cruiser or destroyer sized vessels. The idea is that the ship itself is a rather resilient and large bus, with existing program of record weapons mounted in as stand-alone fashion as possible, similar to how armored fighting vehicles on shore are independent weapon systems. Destroying one Paladin mobile artillery piece does not disable the battery. The only new concept being applied is including tank-like armor on the cylinders housing the weapons and support systems, and ship’s vitals as required. Such armor is already produced for Army and Marine vehicle applications. If space and affordability allow, cargo areas accessible to sea-land-connectors could be provided, as well as rudimentary flight facilities to support helicopters. The SS ATLANTIC CONVEYOR, which transported supplies, Harriers and helicopters for the British military in the Falkland Islands War, is an example. Although some may consider it a cautionary tale since she was sunk by two Exocet missiles, she had no defenses, no armor as suggested in this article, and was a fraction of the size of the vessel proposed here.
A ship similar to this would be relatively expendable compared to a modern CG or DDG. She is not a multi-role vessel torn between competing missions and required ordnance for each. She would also be less expensive since she would not require all the electronics and systems to support multiple missions. She could remain on the gun line far longer than any existing warship, and provide NSFS fire power at a rate much higher than any individual warship. She is not an arsenal ship, because she is not packed with high-end weapons. This also makes her more affordable and more expendable, since the loss of one is not the loss of hundreds of expensive missiles as on the arsenal ship. All the eggs are not in one basket. Instead, it is a basket with a few eggs and lots of padding.
Such a vessel could be assigned to each MPS or APS squadron, or perhaps even Expeditionary Strike Group, to provide NSFS when required. Additionally, the concept is scalable. It could be a smaller cargo ship, or a massive tanker, depending on the best efficiencies as determined by actual architects compared to this author’s musings. The vessel uses existing hulls, tech, and weapons to allow rapid fielding compared to a new warship design. Perhaps this can be the seed of an idea that allows the USN to break the NSFS drought.