What You Need to Know: The Iowa-class battleships, America’s last class of battleships, nearly received a nuclear upgrade during the Cold War. In the 1950s, the U.S. Navy developed the Mk-33 "Katie" nuclear artillery shell for these ships, a 16-inch nuclear shell comparable in yield to the bombs dropped on Hiroshima.

-While storage and launch modifications were considered feasible, the Pentagon ultimately abandoned the project, favoring the Air Force’s long-range bombers. The costly conversion was shelved, leaving only a few of these shells as historical artifacts.

-The potential for nuclear-armed battleships would have offered formidable firepower, though they were ultimately outpaced by carrier and missile innovations.

Iowa: America’s Last Battleship Class Almost Went Nuclear 

America’s love affair with the aircraft carrier was not always a factor in the strategies of the United States Navy. Before the Second World War, it was the battleship that dominated America’s maritime strategies. These incredible platforms were massive and could lob massive shells with insane levels of destruction at distant targets with wanton abandon. 

Battleships, such as the USS Iowa, defined the age of grey steel. The massive shells that battleships could fire at enemies are no longer even produced by America’s defense industrial base.

Even though the aircraft carrier eventually displaced the battleships as America’s premiere surface warship, the Navy still put the handful of battleships it maintained after World War II to effective use. Indeed, battleships served in every major war the United States fought in the post-WWII era from the Korean War down to Desert Storm. The Americans kept innovating the battle wagons to make them comport with the increasing demands of modern combat. 

One such idea that the Navy was kicking around for the Iowa-class battleships was to make these bombastic battleships even more explosive. The Pentagon looked into the feasibility of installing nuclear launchers on these boats.

The Katie 

Known as the Mk-33 AKA “Katie” nuclear artillery shell, the sixteen-inch nuclear shells had yields comparable to the A-bombs dropped on Hiroshima. These weapons could be fired from the battleships without any great need for modifications to the existing weapons platforms on the Iowa-class battleship. The Navy even had fifty “Katie” shells produced and the storage facilities onboard the battleships were made to comport with these lethal armaments. 

Beginning in the 1950s, the Navy wanted to overhaul its handful of battleships. They proposed getting rid of the potent 16-inch guns and replacing them with anti-aircraft and anti-submarine missiles. This would have effectively converted them into guided missile battleships. These enhanced battle wagons would have carried four Regulus II cruise missiles that could have been equipped with nuclear warheads, if necessary.

Yet, the Pentagon ultimately nixed this concept because the Air Force had long-range bombers that could obliterate as many targets farther away than the battleships could hit. What’s more, the investment by the Navy would have been onerous at a time when the services, notably the technical branches, like the Navy and Air Force were vying to create the most effective weapons systems to combat the Soviet threat.

A Missed Opportunity? 

That’s why the Navy started looking at keeping the sixteen-inch guns but creating nuclear shells to be fired from them. It was a much more cost-effective idea to keep the battle wagons up with the nuclear age. Ultimately, the Navy chose not to go through with the project. 

They produced a handful of these weapons, expended only one of the training shells in a peaceful demonstration, using it for construction purposes, and then sent the rest to the National Atomic Museum in Albuquerque, New Mexico. But, had the Navy gone through with upgrading the arsenals of their Iowa-class battleships, the likelihood that these battle wagons would have been even more unstoppable was great

After all, being able to deliver nuclear broadsides accurately and repeatedly upon an enemy target would have likely made even the most implacable foe think twice before engaging with these steel beasts.

Author Experience and Expertise: Brandon J. Weichert

Brandon J. Weichert, a National Interest national security analyst, is a former Congressional staffer and geopolitical analyst who is a contributor at The Washington Times, the Asia Times, and The-Pipeline. He is the author of Winning Space: How America Remains a Superpower, Biohacked: China’s Race to Control Life, and The Shadow War: Iran’s Quest for Supremacy. His next book, A Disaster of Our Own Making: How the West Lost Ukraine, is due October 22 from Encounter Books. Weichert can be followed via Twitter @WeTheBrandon.

All images are Creative Commons or Shutterstock. 

From the Vault

Russia Freaked Out: Why the U.S. Navy 'Unretired' the Iowa-Class Battleships

Battleship vs. Battlecruiser: Iowa-Class vs. Russia's Kirov-Class (Who Wins?)