The U.S. military has thought up many different ways to bring back the battleships. Here is a sample of them.

In the early 1980s, four Iowa -class fast battleships originally built during World War II—Iowa, Missouri, New Jersey and Wisconsin—were taken out of mothballs and returned to active duty.

Nearly 900 feet long and displacing close to 60,000 tons, the battlewagons could fire a nine-gun broadside sending 18 tons of steel and explosives hurtling towards their targets.

The battleships were modernized to include cruise missiles, ship-killing missiles and Phalanx point-defense guns. Returned to the fleet, the ships saw action off the coasts of Lebanon and Iraq. At the end of the Cold War the battleships were retired again. All were slated to become museums.

Few knew, however, that returning the battleships to service in the ’80s had been only part of the plan. The second, more ambitious phase was a radical redesign of the massive warships that would have combined the attributes of battleships and aircraft carriers.

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The resulting ship, a “battlecarrier,” was merely one of many schemes over the span of 30 years to modernize the most powerful American battleships ever built. The various proposals—all of them nixed—had the World War II-era ships carrying hundreds of U.S. Marines or launching Harrier jump jets or even firing atomic projectiles.

A Hole in the Navy:

Before World War II, planners had assumed that the big-gun ships would win wars by duking it out with enemy vessels of the same kind. Pearl Harbor and the Battle of Midway dispelled that notion, as the flexibility and long-range striking power of aircraft carriers proved superior to battleships’ broadsides.

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The battlewagons were relegated to a secondary role in the fleet, shelling shore defenses ahead of landings by the Army and Marines. And after the war, the Navy shed most of its heavy cruisers and battleships while retaining its aircraft carriers. The rush to embrace missiles further reduced the influence of the big-gun vessels , and the era of the battleship appeared to be over for good.

For the U.S. Marine Corps, this was a worrying trend. The seaborne invasion of Inchon during the Korean War showed that the age of amphibious assaults was not yet over. Military planners liked aircraft for their flexibility, but from the Marines’ perspective a ship that could sit off a coastline and bombard it with heavy guns for hours on end was vital.

There was a solution. The four Iowa-class battleships, in mothballs since World War II, were briefly reactivated during the Korean War to provide gunfire support for U.N. forces—and retired again after the war was over.

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For some Navy planners, battleships were back in vogue. There were frequent attempts to return the battlewagons to service.

Nuclear Battleship:

In 1958, the Navy proposed overhauling the Iowa-class ships by removing all of the 16-inch guns and replacing them with anti-aircraft and anti-submarine missiles.

The new “guided missile battleships” would also carry four Regulus II cruise missiles , each of which could flatten a city a thousand miles distant with a nuclear warhead more than 100 times as powerful as the bomb used on Hiroshima.

The result would have certainly been the most powerful battleship ever, but the concept was riddled with inefficiencies. Under the proposal, 2,000 sailors would have had to sail into hostile waters in an expensive, 900-foot vessel to attack just four targets with nuclear weapons. An Air Force bomber could attack as many targets, at a greater range, with fewer than a dozen crew.

And at $1.5 billion in today’s dollars, the conversion would have been expensive.

At the same time, the Navy had put in orders for submarines to carry Polaris ballistic missiles. The proposed missile submarines could attack targets more than twice as far away as the Regulus II-armed battleship could, while carrying four times as many missiles and spending most of their time underwater avoiding detection.

The nuclear battleship concept was dead in the water.

Amphibious Battleship:

In 1961 a new proposal would have utilized the Iowa-class battleships to increase the navy’s troop-carrying capability. The rear turret and its three 16-inch guns would have been removed. In its place would be a hangar and a flight deck capable of carrying 30 helicopters.

The ship would also haul 14 landing craft to bring tanks and vehicles ashore. Accommodations for 1,800 Marines would be added.

Each of the amphibious Iowas would have been a one-ship expeditionary force.

Capable of laying down its own fire support with the remaining six 16-inch guns and deploying a battalion-sized Marine amphibious unit by air and sea, the ship would have been a hive of activity.

But it would still be expensive to convert and operate, and the Navy had many surplus aircraft carriers that could more cheaply be converted to amphibious platforms. Three such older carriers were modified , and the Iowa-class again stayed in mothballs.

Battlecarrier:

The cost of the Vietnam War put a temporary hold on talk of reviving the Iowas in some new form. One of the battleships, New Jersey, was briefly reactivated to serve in Vietnam.

In the early 1980s, the Reagan Administration began an ambitious shipbuilding program. It was decided to yet again bring back the four Iowas. In phase one, the ships were modernized with the addition of Tomahawk land attack missiles, Harpoon anti-ship missiles and Phalanx defense guns. By the mid-1980s, all four had returned to duty.

There was a phase two that was never executed , and it was more interesting.

This phase again involved removing the rear 16-inch gun turret. In its place would be built an overhanging flight deck and two forward-facing ski jumps that would hurl Marine Corps Harrier jump jets into the air. The ship would carry up to 20 Harriers, as well as a hangar and an aircraft elevator.

And that’s not all. Nestled between the two ski jumps would be a large field of missile silos, each holding Standard anti-aircraft or Tomahawk land-attack cruise missiles.

The firepower of the battleships—and their destructive range—would have increased substantially. Trading one turret for 20 Harrier jets was a pretty good deal. Add the Tomahawks and their ability to strike with precision at a thousand miles and the improvements looked even better. The resulting warship would have equaled the firepower of a Nimitz-class supercarrier.

But as before, the Iowas’ inherent inefficiencies worked against them. With a crew of nearly 2,000 each, the ships’ high personnel costs made them prohibitively expensive to run in an all-volunteer navy. Harrier jets could already be carried by the Tarawa -class landing ships , and missile silos were proliferating across the fleet.

The Navy came to the conclusion that if the country was going to get its money’s worth from the four battleships, the vessels had to concentrate on their unique abilities: firing massive artillery shells at the enemy.

That meant keeping all three main gun turrets. The cool conversion schemes would have to stay just that, schemes.

Future Battlewagon:

Today the naval gunfire argument rages on. Even in the age of drones and precision warfare there are still occasional calls to bring the heavily manned , imprecise Iowa class back to service. There’s a certain romance to battleships, and having four Iowas sitting around in good condition has beguiled naval enthusiasts and planners for more than 60 years with schemes to bring them back.

The Zumwalt -class destroyers will go a long way towards providing battleship-quality naval gunfire support for the Marines. Minimally manned, relatively small, stealthy and precise, the Zumwalts are the antithesis of the Iowas, but functionally their successors.

Although each Zumwalt can only provide the explosive mass of a single one of an Iowa’s 16-inch guns, the newer ship can fire its smaller shells with GPS-aided precision up to 83 miles away, versus 20 miles for an Iowa.

Should the Zumwalt design be successful, the torch of the battleship could finally be transferred to them, and the Iowas can finally slumber in peace as museums, safe from the schemes of those who would revive them.