A new proposal published by the U.S. Naval Institute suggests purchasing merchant ships and converting them to carry and fire ballistic missiles in order to support the nation’s growing need for a larger naval presence around the world. As crazy as it sounds, the proposal actually makes some interesting points.

The U.S. Navy faces a unique challenge. It serves as the nation’s primary means of force projection, but maintaining a global presence is incredibly taxing on the branch’s fleet and personnel. In order to maintain America’s stabilizing presence in shipping lanes throughout the world while allocating sufficient military resources to potential and ongoing conflicts, the Navy needs to grow. The problem is finding a way to pay for it.

President Trump championed the call for a 355-ship Navy along the campaign trail, but even the recent bumps to the national defense budget can’t possibly allow for such a rapid build of state-of-the-art warships. The fleet, which currently sits at around 270 vessels, is expected to expand in the coming years, but as older ships complete service lives, the total size of the fleet will likely stay in the 270-290 range for decades to come. As a result, there are proposals to keep older ships in service for longer, swelling the numbers toward that 355-ship goal. But that plan also fails to really appreciate the nuts and bolts of that 355-ship figure. It’s not enough to have that many ships, they need to be the right ones with the right capabilities for the Navy’s varied obligations.

The answer? Purchase low-cost merchant ships and convert them to carry and operate modular weapon systems, at least according to a team that includes retired Navy Captain R. Robinson Harris and Retired Marine Corps Colonel T.X. Hammes. The point wouldn’t be to put these merchant ships in heavily-contested waters, but rather to let them adopt low-threat operations such as steaming in circles near allied nations to provide Aegis missile defense support. The U.S. Naval Institute’s proposal states:

“Chief of Naval Operations (CNO) Admiral John Richardson has voiced concern about operational restrictions imposed on the fleet by the Navy’s ballistic-missile defense (BMD) ships. [1] The CNO explains that the BMD ships are restricted to confined operating areas—’little boxes,’ as he puts it. His concern appears not to be with the BMD mission, but rather that with only 280-some ships, restricting the movements of the BMD assets means that there are other important missions elsewhere that the Navy cannot fulfill.”

An important element of the push for a larger Navy is the need for more vertical launch system (VLS) cells, or put plainly, tubes from which to launch missiles. Ballistic missiles of varying sorts are the Navy’s go-to weapon for everything from ballistic missile defense and anti-ship operations to surface-to-surface engagements like last year’s missile strikes in Syria. These launch tubes represent the kinetic end of the Aegis  apparatus as well, which forced many of the nation’s Arleigh Burke-class guided missile destroyers into maintaining missile defense postures.

Instead, these low-threat operations could be absorbed, according to the proposal, by merchant ships purchased and converted to house VLS cells. Because the likelihood of facing off against anti-ship weaponry is extremely limited off the coast of Japan, for instance, the merchant ship wouldn’t encounter threats better battled by a destroyer.

In effect, these former commercial ships would become a modern version of the classic “arsenal ship” concept: pile a ton of ordnance on a ship (or aircraft) and then use existing military assets to bolster its targeting capabilities. The merchant vessel effectively becomes an “on-demand remote-magazine,” offering a great deal of firepower when it’s needed for a comparably smaller cost.

Proponents even suggest that by adding some of these arsenal merchant ships to a carrier strike group, modular missile weapon systems could help the fleet deliver more firepower on shore before American carriers get close enough to begin launching sorties. This is approximately 700 miles once the MQ-25 Stingray begins service as a refueler.

The U.S. Naval Institute’s proposal indicates these merchant ships are much cheaper than purpose-building other means of missile delivery. Further, that a war in the Pacific would likely result in even cheaper procurements as commercial shipping was affected by the conflict.

“Because the expensive sensor suites will be off-hull, the cost to convert such ships to missile platforms should be modest, assuming the employment of standard Mark 41 VLS 8-cell modules or purpose-built ConEx boxes. Using standard 20- or 40-ft. long freight containers offers the advantage of several different loading systems and intermodal handling systems ashore.”

Because these “missile merchant” ships weren’t built around managing VLS weapon systems, the storage alloted on the vessel would be important to incorporate the support equipment needed for combat operations; though much of the target acquisition and processing work would still be done via existing naval systems located in submersible, surface, and airborne assets. The ship would also need modular defensive systems, but would likely rely heavily on other Naval assets and foresight regarding placement for security.

However, if these missile merchants were in hotly-contested waters, their past lives in the commercial sector may actually come in handy.

“Many targeting systems rely on inverse synthetic-aperture radar, which produces a low-resolution image of its target for identification, revealing only a simplified shape. In heavily-trafficked areas, a missile merchant without sensor masts would be hard to discern from other merchant ships at range.”

Ultimately, it seems unlikely the U.S. Navy would adopt such a radical approach to expanding the fleet without good reason. For instance, if a war with China began to seem unavoidable, the U.S. could reallocate Naval resources to the Pacific for a short time without much trouble, but a lasting conflict would undoubtedly require some creative management of assets if the U.S. Navy hopes to maintain a presence outside that theater.

If such a time were to come, this proposal, however unlikely, could be just the ticket to winning the next great naval war. You can read the full U.S. Naval Institute proposal here.