Fire Control on Iowa-class Battleships

By Michael Frutig, National Museum of the American Sailor Intern

An Iowa-class battleship was the single most powerful ship ever built for the United States Navy, comprised of 45,000 tons of steel and equipped with the largest guns ever fitted to an American ship. Nine 16-inch guns sat in three-gun turrets; each barrel was capable of firing on its own. These guns could fire a shell that weighed either 1,900 (HE) or 2,700 (AP) pounds a distance of twenty-four miles.

Mark 38 main battery director with Mark 8 fire control radar on top. Picture was taken during commissioning ceremonies on the ship’s fantail, at the New York Navy Yard, February 22, 1943.

The USS Iowa (BB 61), USS Missouri (BB 63), USS New Jersey (BB 62), and USS Wisconsin (BB 64), were ships of such immense power that many people believe that they were the largest during World War II however they were not.

The Japanese Yamato-class battleships were the largest battleships ever built in history. Displacing 72,000 tons, these super battleships were nearly twice the size of the Iowa-class. Each ship fired shells weighing 3,300 pounds and could shoot a staggering twenty-six miles. Two such ships were built, and they were a massive threat to the American fleet. Yet despite their massive size, most historians believe that because of Fire Control, the Iowa-class would have defeated the leviathan Yamato-class had they ever engaged.

Fire Control is a system which corrects the shots of the guns. On the Iowa-class ships, there were two important parts to this system. The first key component of Fire Control was sailors in the Ship Gun Fire-Control System or GFCS. They were stationed on the highest part of the ship, which looked like a crow’s nest. This area was crewed by a number of sailors whose job was to use radar and range finders to track the fall of shot. As these ships were providing indirect fire, sailors needed to track the fall of shot to make corrections. This job was fast-paced work as each barrel could fire at a pace of two shells per minute.

Drawing for Wikipedia by Voytek S based on original found in “Naval Ordnance and Gunnery – 1952” Navpers 16116-B, published by the Navy’s Navy Personnel Command/Bureau of Naval Personnel.

The second key component of Fire Control involved trajectory plotting. Once the shells were fired and GFCS captured the shot’s data, the data was sent to a plotting room deep in the citadel of the ship. Here, Fire Controlmen plotted the trajectory of the next shots. Aided by analog computers, the plotting rooms provided instructions to the gun barrel operators. This process was so accurate that in all the ship to shore bombardments in which Iowa-class ships participated, they were the most accurate. During the bombardment of Iwo Jima, the New Jersey, coupled with the power of each shell, needed only to fire two shots to destroy any target completely.

Scene in the main battery plotting room of the USS Missouri (BB 63) during operations off Korea on September 17, 1950. 80-G-420319, Official U.S. Navy Photograph, now in the collections of the National Archives.

Fire Control on Iowa-class battleships was fast-paced, challenging work. The task required great skill and professionalism from the sailors who tracked each shot, but the results were undeniable. Yamato-class ships relied on manual range finding and did not use computers to speed up their corrections. A U.S. Navy warship could also keep its devastating accuracy at night because of its Fire Control skill, the Japanese could not.

It is no surprise that despite the massive size difference, historians agree that the Iowa-class battleships would emerge victorious from any battle with surface ships. While it was not the largest ship of the Second World War, due to Fire Controlmen, the American Iowa-class battleship reigned as the supreme naval artillery of the war.

Want to learn more about Naval gunnery check out our Defending the Seas and Sky article by clicking here.

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