November 01, 2017

USS Iowa (BB-61) Part 2 - Early Service in the Pacific

On January 7th, 1944, Iowa transited the Panama Canal, ending her wartime service in the Atlantic. She was en route to join the US offensive against Japan in the Central Pacific. Her newly-commissioned sister New Jersey joined her to form Battleship Division 7, with Iowa serving as the flagship. They joined the 5th Fleet on the 22nd, and the next day sailed as carrier-group escorts for the invasion of Kwajalein in the Marshall Islands. This invasion, though eventful on the ground, saw nothing of note for Iowa. Her first combat action came on February 17th, as part of a carrier raid on the Japanese naval base at Truk to cover the landings on Eniwetok Atoll. The raid began at dawn that day, as aircraft from nine carriers pounded airfields and shipping. To catch any escapees, Admiral Spruance, commanding the American fleet, ordered BatDiv 7, with escorting cruisers and destroyers, to make a sweep around Truk to intercept any escaping enemy ships.

Iowa at sea shortly after arriving in the Pacific

To quote Samuel Eliot Morison,1 “As Spruance’s group steamed in the direction of reported enemy ships, mighty Iowa at 1118 was attacked by a bold ‘Zeke.’2 It made a near-miss alongside the wing of the bridge where Admiral Hustvedt3 was eating his lunch. ‘That was my bomb’ said the Admiral, and went on eating. The ‘Zeke’ got away.”

A6M3 Zero

At this point, tragedy struck. An American plane attempting to deliver a message was shot down by Iowa’s guns due to a misunderstanding on the part of an AA gun crew, and all aboard were killed.

An hour and a half later, Iowa fired her guns at enemy surface warships for the first and only time in her career. One of New Jersey’s planes spotted three enemy ships well ahead of the task group and both ships accelerated to 30 knots. Iowa’s first target was the light cruiser Katori, the recipient of forty-six 16” HC shells and 124 projectiles from the 5” battery. Each of the eight salvos straddled Katori, although it’s not certain how many hits were made before Katori sank, thanks to the combined fire of Iowa and her escorting cruisers.

Katori burning off Truk

At the same time as the first salvo went out, three torpedoes very narrowly missed Iowa, one down the port side, one close astern, and one 100-200 yards ahead. The first had come from the destroyer Mikaze, the other two from Katori. The action report mentions that the 5”, 40mm and 20mm batteries had all been trained to fire on torpedoes without orders, and did so.

Iowa was about to engage the Mikaze when the Japanese destroyer sank, so she turned her fire to the other destroyer, Nowaki. Nowaki was at a range of 37,500 yards when fire began, and the first salvo was a straddle.4 Unfortunately, neither Iowa nor New Jersey managed to land a hit on Nowaki, who had just enough margin of speed to escape. Iowa fired a total of 5 salvos at Nowaki, totaling 40 projectiles.5 Nowaki would be sunk in October as part of the Battle of Leyte Gulf.


The rest of the sweep was uneventful, and Iowa rejoined the carrier force as it retired to Kwajalein. She escorted the first carrier raid on the Marianas a week later, which was uneventful for her, and a major success for the US as a whole.

Her next action came in mid-March, as Vice Admiral Willis A Lee, commander of the Fifth Fleet battle line, led Iowa and New Jersey on a bombardment mission to Mili Atoll. For two hours on the morning of March 18th, Iowa poured fire into the island unopposed, before the Japanese coastal defense guns opened fire. At 0940, Iowa received her first battle damage, a 6” hit on the side plate of Turret 2.6

This hit obviously failed to pierce the armor7 and merely destroyed the left gun pointer’s telescope, broke the glass covering the left ear of the turret rangefinder, and stripped away some of the weather/gas seal between the turret and the barbette. Two men inside the turret suffered minor wounds from shrapnel that entered through the pointer’s telescope. The deck nearby and the shield of the 40mm mount next to the turret were also sprayed with fragments, but none of the crew outside were injured. There’s a small dent there to this day, although it would barely be visible if we hadn’t painted an arrow pointing to it.

The results of the hit on Turret II

The 5” battery continued to fire at the shore guns while the main battery was ordered back to bombardment duty, but the counterbattery fire was insufficient to stop a second 6”8 hit 15 minutes later. This one struck further aft, at Frame 134, near the aft 5” mounts and about four feet below the main deck. It blew a 30” by 50” hole in the side of the ship, opening a void space and doing minor damage. Nobody was hurt, and the damage was quickly repaired after the action. For all that, Iowa got off lightly. The Action Report says that there were 10 shots which landed less than 50 yds from the ship, and that Iowa was straddled at least 10 times. Shortly after the second hit, Iowa and New Jersey withdrew to allow planes from the carrier Lexington to bomb the island, then resumed bombardment. By this point, the coastal guns had gotten smart, and stayed silent. A total of 180 rounds of 16” and 852 of 5” were expended by Iowa on Mili.

Iowa in early 1944

The Action Report also had some very interesting details on damage caused by Iowa’s own gunfire. A total of 8 quick-acting doors9 were rendered inoperable, fittings to the sinks in two officer’s staterooms were knocked loose, causing minor flooding when the water was turned back on before the damage was discovered, extensive damage was done to the lighter structures on the bridge, and power was lost to two 40mm mounts due to the circuit breakers tripping under the shock. The same problem knocked radar systems offline.

Next time we'll look more at Iowa's service in the Pacific, as the American offensive went into high gear.

1 History of US Naval Operations in World War II Volume 7, pg 326-328

2 This was the reporting name for the Zero.

3 Commander of BatDiv 7

4 A straddle is when shells fall both long and short of the target, and essentially indicates that the guns are on target, and will eventually hit. This was a rather incredible feat, quite possibly the longest-range straddle ever. It was certainly the longest range American battleships ever engaged an enemy ship at. Making it even more impressive, the cams for the HC shells had not been installed yet, so the fire was controlled using the AP cams with manually-calculated updates to compensate for the different ballistics of the HC shells.

5 A burr had been discovered on the breech plug of the left gun of Turret 3 after the Katori was sunk, and it was still being removed at this point, so each salvo was only 8 guns.

6 Many sources including DANFS give the caliber of the hits as 4.7”. I asked Iowa’s curator, Dave Way, about this, and he believes that the misconception came from a much larger, circular divot bored into the port side of Turret II near the rangefinder. This indentation is 4.7” in diameter, and was made in the 80s as an attachment for some sort of instrumentation. The crew apparently came to believe that this was the location of the shell hit, and 4.7” became the reported caliber of the shell. I actually spent my first month as a tour guide pointing people at the wrong place.

8 Some sources say the shell was 5" or 5.5".

9 Watertight doors with a mechanism that operated all of the dogs from a single handle as opposed to individual dogs.


  1. June 19, 2020Ian Argent said...

    " The action report mentions that the 5”, 40mm and 20mm batteries had all be trained to fire on torpedoes without orders, and did so. "

    That looks like it should either be "had all been trained" or "had to be all trained" and context supports the former.

  2. June 19, 2020bean said...

    Fixed. Wow, that was a long time for that typo to survive.

Comments from SlateStarCodex:

  • bean says:

    History of the Iowa, Part 2 is up at Naval Gazing. I believe comment mirroring is still broken.

    • Said Achmiz says:

      Actually… bizarrely… further testing reveals that it seems to work for some SSC posts but not others. (Try it with this one, for example.)

      I’m continuing to look into the cause!

      • bean says:

        Right. Comment mirroring is now working, at least on that post.

      • Said Achmiz says:

        Comment mirroring is now working.

        What was the problem? Two evils conspired to produce this glitch: lack of foresight and website bloat.

        The library I use to parse a retrieved web page had a constant in it, MAX_FILE_SIZE (meant, no doubt, to prevent undue load on one’s web server, or hanging server processes, that might be caused by attempting to retrieve and parse a giant remote web page that some malicious person placed there as an attack). If a retrieved page is found to be larger than MAX_FILE_SIZE, parsing is not attempted.

        This library was last updated in 2014. MAX_FILE_SIZE was set to a very generous 600 kilobytes. After all (thought the fellow who wrote this parsing library), what madman would create a webpage where the HTML—just the HTML—would exceed 600K in size?!

        Clearly, our man has never read SlateStarCodex. This page, for example, is over 800K. (That’s just the page, now; we’re not counting the 9 stylesheet files, the 12 Javascript files, or the 120 image files that make up the webpage as a whole.)

        These are the sad times in which we live.

        P.S. I increased MAX_FILE_SIZE tenfold, and now all is well. After all—what madman would create a webpage where the HTML, by itself, would exceed 6 MB in size?!

        • Deiseach says:

          After all (thought the fellow who wrote this parsing library), what madman would create a webpage where the HTML—just the HTML—would exceed 600K in size?!

          Clearly, our man has never read SlateStarCodex.

          I like the identification with Mad Science this gives the whole site, and by extension its readers.

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