USS Illinois: The Forgotten Iowa-Class Battleship The Navy Never Finished

Key Points and Summary: The USS Illinois (BB-65) was planned as an Iowa-class battleship during World War II, embodying the Navy’s reliance on heavily armored “battlewagons.”

-Ordered in 1940 and partially built, the Illinois was intended to feature welded construction and formidable 16-inch Mark 7 guns.

-However, the attack on Pearl Harbor and victories at Coral Sea and Midway showcased the dominance of aircraft carriers, rendering battleships less critical.

-Construction slowed in 1942 and was halted entirely after Japan’s surrender in 1945.

-The Illinois was dismantled in 1958, leaving it as a testament to shifting naval strategies in the face of modern warfare.

USS Illinois (BB-65): The Battleship That Never Sailed

At the onset of World War II, the United States and the US Navy were still married to the idea that the battleship, not the aircraft carrier, was the primary weapon of the fleet. 

The US built four Iowa-class battleships but wanted a new, more heavily armored design, with the USS Illinois (BB-65) and the USS Kentucky (BB-66) as the first of the Montana-class battleships. Japan’s invasion of China in 1937 changed that. The Navy ordered the USS Illinois and USS Kentucky to be built as Iowa-class battleships. 

The stunning Japanese victory at Pearl Harbor, where carrier-borne aircraft caught the American fleet at anchor and sunk or damaged eight battleships, forced the Navy to rethink their strategy to a more carrier-based fleet. 

After the American victories in the Coral Sea and at Midway, where, for the first time, the opposing fleets never saw one another, the die was cast. 

The US stopped construction on the Illinois in 1942, canceled it in 1945, and finally scrapped it in 1958. 

Background Of the USS Illinois Battleship

During the late 1930s, the Navy prepared for an eventual war with the Empire of Japan. 

The Japanese were expanding their empire westward. The Japanese Navy was growing quickly, and their fleet with many aircraft carriers and fast Kongō-class battlecruisers was a force to be reckoned with. 

Many American strategists still believed that a slower, heavily armored, and armed fleet of battlewagons was the way to go.

 Shortly after Japan invaded China in 1937, Carl Vinson, a Democratic Congressman from Georgia, sponsored the “Second Vinson Act of 1938.” 

This bill authorized the construction of 105,000 tons of battleships (the first three Iowa-class ships were built under this authorization), 40,000 tons of aircraft carriers (expended on Hornet), 68,754 tons of cruisers (expended on 4 Cleveland and 4 Atlanta-class light cruisers), 38,000 tons of destroyers and 13,658 tons of submarines (eight vessels were built under this authorization – SS-204 to SS-211), together with various smaller ships.

USS New Jersey Iowa-Class Battleship. Image Credit: US Navy.

Four Iowa-class battleships were to be built, and the USS Illinois and USS Kentucky were to be the first Montana-class battleships. 

However, in 1940, the need to adopt industrial mobilization as the threat of war loomed forced the Navy to place new designs on hold, and as a result, BB-65 and BB-66 were ordered to the Iowa design.

The Changing Of Naval Warfare Forces Changes In Planning

The Second Vinson Act of 1938 had the US over $1 billion to expand the Navy by 20 percent. That billion dollars then is worth about $22,543,214,285.71 today. 

In an economy still in the depths of a depression, in 1938 was a big amount, which speaks to the seriousness that the country put the potential war because of Japan’s aggressiveness.

When the USS Illinois was ordered in 1940, it was changed to an Iowa-class battleship to facilitate shipyard building. The keel for the USS Illinois and USS Kentucky were laid in 1942, but the face of war had changed dramatically, and so would plans for the battlewagon. 

The Japanese sneak attack at Pearl Harbor had devastated the Pacific fleet’s battleships. The Coral Sea and Midway battles showcased the astonishing ability to project power with the aircraft carrier. The battleship had to get close to the enemy to sink his vessels. The aircraft carrier could strike far from its fleet and sink the battleships long before they were in range to fire their guns. 

Production ceased in 1942 on the Illinois and Kentucky.

USS Illinois BB-65 Specs, Had It Been Built

With a displacement of 45,000 tons; a length of 887 feet and three inches; a beam of 108 feet, two inches; and a draught of 37 feet, two inches; the Iowa-class were also the largest battleships to ever be built by the U.S. Navy. 

The Iowa-class were the most heavily armored U.S. warships ever built. The armor belt was inside the hull and was 12.1 inches at its thickest. The turrets had 19.7-inches of armor, while the decks were plated with 7.5-inches of armor. Having taken a battleship tour, a guide said a 500-pound bomb could be dropped on the turret, and it would do nothing but raise the dust inside. While that seems dubious, I’ll take his word for it. 

Iowa-class. Image Credit: Creative Commons.

The Illinois would have been the first battleship to have an all-welded construction. This would have reduced weight over the previous riveted/welded hull and increased strength.

The USS Illinois and Kentucky armament would have been the same as the other Iowa-class battleships. The primary weapons were the battery of nine 16-inch (406mm)/50 caliber Mark 7 guns, each of which could fire a 2,700-pound armor-piercing shell up to 20 miles.

The secondary armament was a battery of twenty 5-inch (127mm)/38 caliber guns arranged in 10 turrets, which could have fired at a range up to 10 miles away. These weapons proved to be highly effective as anti-aircraft defense, in-close ship battles, or as naval gunfire support for amphibious landings.

Work Slows to a Crawl and Stops:

Work was virtually stopped on the USS Illinois in 1942 and only moved forward slowly as it was deemed a non-priority through early 1945. 

However, on August 11 – just two days after the second atomic bomb dropped on Japan – work ceased. 

BB-65 was struck from the Naval Vessel Registry just a day later. Although some proposals were sent to change her build, she remained unused.

The unfinished hull remained as a parts hulk until she was dismantled in 1958.

About the Author 

Steve Balestrieri is a 19FortyFive National Security Columnist. He served as a US Army Special Forces NCO and Warrant Officer. In addition to writing for 19FortyFive, he covers the NFL for PatsFans.com and is a member of the Pro Football Writers of America (PFWA). His work was regularly featured in other military publications.