February 11, 2018

Amphibious Warfare Part 3

Tarawa, one of the Gilbert Islands, was targeted by the US as the first stepping stone in the drive across the central Pacific that had been planned since just after WWI. It marked a new kind of amphibious operation for the Americans, landing on a small atoll into the teeth of Japanese defenses, and far from land-based air support. The assault on Tarawa, and the simultaneous attack on nearby Makin,1 involved approximately 200 ships, 27,600 assault troops, 7,600 garrison troops, 6,000 vehicles and 117,000 tons of cargo.

Bodies on the beach, November 22nd 1943

The troops who landed on Betito Island, the fleck of Tarawa with the all-important airfield, belonged mostly to the 2nd Marine Division, staged out of New Zealand. They were carried to their target by the Southern Attack Force under Rear Admiral Harry W Hill. This force of 16 transports, 3 battleships, 5 cruisers, 5 escort carriers, 21 destroyers, 2 minesweepers, 1 LSD and 3 LSTs began landing operations early on the 20th of November, 1943.

Map of Tarawa

There were three sets of suitable beaches, designated Black, Green, and Red. Black was on the outside of the atoll,2 while Green was on the end of the island, and Red faced the lagoon. The US had done extensive reconnaissance,3 and the heavy defenses on Black and Green meant that Red was selected as the landing site. This did mean that the run-in from the ships to the beach would be very long, but it couldn't be helped.

Landing Craft, Vehicle Personnel (LCVP)

The transports began lowering their boats at 0355. The troops mostly went into LCVPs, 36' boats designed to carry 36 men or a jeep onto a beach and offload them over a large ramp in the front. After each was lowered, it would come alongside the transport and the troops would go down a scrambling net. When it was loaded, it would pull off and circle nearby until it was time to go. The first four waves, though, rendezvoused with the LSTs to transfer their troops.

LST unloading at Guadalcanal

The Landing Ship Tank, or LST, was one of the ships designed at Churchill's request as part of his plan to retake Europe. It was a 5,000 ton seagoing vessel designed to run onto a beach and unload about 20 tanks directly, although in practice they were more often used to carry trucks and cargo. In this case, the LSTs carried a vehicle that would be the key to Tarawa.

LVT knocked out on Tarawa

The Landing Vehicle Tracked (LVT) had its origins in a craft designed to rescue crashed pilots from the Florida Everglades. It was an amphibious vehicle, propelled by tracks both in the water and on land. It wasn't particularly good in either environment, but it could crawl across reefs and drop its 24 passengers off on dry ground.

Maryland bombarding Tarawa

The action began at 0503, when a Japanese gun opened fire on the battleship Maryland, flagship of the task force. For the next hour the warships dueled with guns ashore, until an air strike from the fleet carriers forced them to check fire. Then the scheduled bombardment began, about 3,000 tons of naval projectiles landing on the island in the space of 70 minutes, along with more aerial munitions. The Americans expected this would be enough to daze the defenders, but they had badly underestimated the toughness of the Japanese fortifications. Their coconut log and coral dugouts withstood all but direct hits, although the bombardment did silence most of the heavier Japanese artillery and disrupt communications.

Well deck of LSD Casa Grande

Under cover of this bombardment, minesweepers Pursuit and Requisite swept a channel from the transport area into the lagoon, then led in a pair of destroyers. These four ships provided all of the direct fire support that day, although in later invasions, such ships would be augmented by converted landing craft. The next ship in was the Landing Ship Dock (LSD) Ashland, a conceptual descendant of the Japanese landing craft carriers. She carried the tanks for the initial assault, loaded in LCMs, essentially larger LCVPs designed to carry a tank or two.

Marines wading ashore

The first three waves, which were to land at three-minute intervals, were in the LVTs. Because of heavier than expected sea conditions, the LVTs were slow, and the first Marines, originally scheduled to land at 0830, didn't touch down until 0913. They were met by intense Japanese fire, and the unarmored LVTs suffered badly. They were unable to cross the seawall, and most of the Marines that did make it ashore were pinned down there. Worse, the planners had not been able to predict the tides accurately, and November 20th had no high tide. This meant that all of the landing craft except the LVTs were stuck on the reef about 500 yards offshore. A few tanks managed to wade ashore, but they were not used very effectively, and most were quickly knocked out.

Marines taking cover against the sea wall

The situation that developed was one of the worst in the long and illustrious history of the United States Marine Corps. About 1,500 men were trapped on a narrow strip of beach, while thousands more were stranded offshore. Those ashore slowly knocked out the Japanese positions with flamethrowers and TNT, their rifles and grenades proving mostly ineffective. Worse, the complexities of the amphibious operation meant that almost all of the troops, equipment, and supplies intended for landing on the first day were in their boats before the first wave ran into trouble, making it difficult for the Marines ashore to get the support they needed. The transport commanders stuck to the unloading plan and by midafternoon there were 100 landing craft full of unwanted supplies milling about in the lagoon. By the end of the day, 5,000 men had gotten ashore, and 1,500 of them had become casualties.

The tide finally turned, both literally and figuratively, by noon the next day. Reinforcements had been trickling in all night, but the added impulse of the fresh landings meant that the Marines could break out and begin to clear the island.

One of the beaches after the battle

The battle of Tarawa lasted only 76 hours, and of the 18,309 officers and men who landed, 1099 were killed and 2101 were wounded, a casualty rate of 17%. Casualties among the defenders, over 4,500 strong, were near-total. Only 17 were captured, along with 129 Korean laborers.

Tarawa was not the largest or most sophisticated operation of the war, but it was a vital one on the long road to Tokyo Bay, and a good example of the sophisticated techniques required to seize a heavily defended beachhead. Next time, I'm going to cover the operations that took Allied forces deep into Germany and to the doorstep of Japan.

If I haven't managed to satisfy your hunger for details on US landing doctrine, here are some manuals.

1 I'm not going to cover Makin for reasons of space, and because it wouldn't really add to my main purpose of illustrating how a WWII amphibious operation worked. In the end, it was a much less difficult fight than Tarawa.

2 An atoll is basically a ring of coral, with a lagoon in the center. In some areas, the coral pokes above the sea surface, forming islands, while areas of lower coral form gaps in the ring that allow ships to enter.

3 The US guessed to within 64 men how many defenders there were. They got a good photo of the Japanese outhouses, and by working out how big they were, how many holes that meant they had, and then looking up how many men per hole Japanese doctrine called for.


  1. February 11, 2018CatCube said...

    The best anecdote about this is that the US guessed to within 64 men how many defenders there were. They got a good photo of the Japanese outhouses, and by working out how big they were, how many holes that meant they had, and then looking up how many men per hole Japanese doctrine called for, they made a very accurate estimate.

    That reminds me of something my drill sergeant was telling us (while making us police up trash at a training site we were leaving): One thing that SF does that you don't hear about a lot is counting turds. If you know roughly how long a unit has been in a bivouac, using the assumption that a man defecates about once per day, simple division will enable you to work out the size of a small unit you're following. The context of the drill sergeant's remarks was the emphasis on trash discipline, because you can use the same trick for field rations, where dividing the spent field rations by 3×number of days indicates the unit size. So a well-disciplined unit will either bury or backhaul all refuse to avoid leaking information.

  2. February 11, 2018bean said...

    Why do I have this feeling that there's a manual somewhere for the creation of something like "Fake Stool, Human, Field Expedient"?

  3. February 11, 2018Johan Larson said...

    Is 17% casualties a lot in this context? It doesn't sound like a lot, but I'm not in the habit of assaulting fortified positions, so I can't judge from experience.

  4. February 11, 2018bean said...

    17% is a lot for large units, yes. A typical rule of thumb is that 10% casualties is enough to render a unit significantly less effective. A lot of the people in question are clerks, artillerymen, and the like, and the casualties are concentrated in the front-line units. I don't have numbers to hand for the first units ashore, but I suspect the casualties exceeded 50% among them.

  5. February 12, 2018quaelegit said...

    @CatCube -- in Cryptonomicon at one point they need to create a fake observation post, and the sergeant has the important job of faking the latrines -- you see, not only do you need the correct number of fake turds (I'm pretty sure they used a term very similar to bean's suggestion but don't have the book on hand), you also need to bury them plausibly. Also important -- scattering a plausible amount of cigarette butts about the premises.

    On topic -- the pictures in this post are... quite something. I guess because my main comparison is Robert Capa's D-Day photos, which I think were taken at the beginning of the battle, whereas these are aftermath... there are just so many dead people... Really drives the carnage home.

  6. February 12, 2018Aapje said...

    [picture description:] Debris on the beach

    Pretty cold when the picture shows mainly casualties.

    The Landing Ship Tank [...] was a 5,000 ton seagoing vessel designed to run onto a beach

    Was the ship then stuck on the beach or could it extricate itself after unloading?

  7. February 12, 2018bean said...


    On topic -- the pictures in this post are... quite something. I guess because my main comparison is Robert Capa’s D-Day photos, which I think were taken at the beginning of the battle, whereas these are aftermath... there are just so many dead people... Really drives the carnage home.

    Some of that is that I've found it hard to get in-battle photos for this. I think most of the war photographers were employed with various commercial outfits, who still hold the copyright to their photos. So I'm stuck with stuff the military took, and all of their people had bigger concerns than documenting the battle while it was going on.


    Pretty cold when the picture shows mainly casualties.

    Yeah. Re-reading, I'm not sure why I chose that line, and have thus modified it.

    Was the ship then stuck on the beach or could it extricate itself after unloading?

    They'd drop an anchor on the way in, then haul themselves off. Hopefully. Ships did get stuck or broach (turn sideways) although it was worse for the smaller landing craft.

  8. February 12, 2018Tony Zbaraschuk said...

    Also, tides are an element -- if you land at low tide or half-tide, then the rising tide will float your boats and let them go back to pick up another load. The British had learned this lesson at least as early as the Napoleonic Wars, and it was part of the planning cycle for D-day. (One of the reasons the Germans were surprised on June 6; they thought the Allies would land at high tide to minimize the distance troops had to cover across the open beach. The naval planner chose to land at low and half-tide partly to avoid all the obstacles around the high-tide line, but also to allow the landing craft to be refloated and returned more quickly.)

    There was some concern originally that LSTs would break their backs if they went ashore and then the tide went down around them. In practice this turned out not to be the case, so an LST could be beached and unloaded over the next few hours and then refloated safely.)

  9. February 12, 2018bean said...

    Tides were an element of almost all amphibious planning. In the Med, they weren't really a big deal, but everywhere else (where they had good tidal data) landing dates were set by the need for the tide to be at the right time of day. Invasions run by the Army (most of the ones in Europe) put the troops ashore in the dark in an attempt to gain surprise. The Navy usually would approach under cover of darkness, and then land after daylight to allow better fire support and navigation.

    Re the LSTs, I think that stranding was part of the design case. I don't recall any instances of full strading during WWII, although it was rather notably done at Inchon.

Comments from SlateStarCodex:

  • bean says:

    Today, Naval Gazing looks at the invasion of Tarawa, as an example of amphibious warfare in WWII.

    • Urstoff says:

      Thanks for this post. Tarawa has always interested me, as my grandfather was on the Heywood and, with Eddie Albert (of Green Acres fame), took small craft to rescue injured marines in the water and take them back to the ship.

      Why did the US decide to take Tarawa rather than just bomb and bypass it like they did with Truk?

      • bean says:

        Because we needed an airfield there to support the drive into the Marshalls, IIRC. The big Japanese bases (notably Truk and Rabaul) were bypassed because they were more trouble than they were worth to take, given that we could build bases that were 90+% as good on nearby islands that were a lot less heavily defended. Manaus is the most obvious example. Tarawa was also a rude wakeup call to how hard that kind of campaign could be, too. I’m not sure when Truk and Rabaul were discarded as targets, but I think Truk at least was after Tarawa was taken.

        • gbdub says:

          We needed the Marshalls to take the Marianas – Wikipedia claims Tarawa could cut off direct communications from Hawaii, but I’m not clear on why, since it is southeast of the Marshalls. Maybe it was too big of a base to leave in a position to harass the Marshalls campaign. But then Truk is smack between the Marshalls, Marianas, and Solomon Islands, so you think that would be more critical.

          • bean says:

            I’d have to check Morison to be sure, but I don’t think Wiki is right on this. The key realization of 1943-1944 was that so long as we could take bases and control the flow of supplies, we didn’t actually have to take the Japanese strongholds away from them. But the bases were necessary to support the blockade and to help the onward advance. Tarawa was taken because we needed one of those bases, not because of how much of a threat it was. During the Marshalls campaign, it was important as a base for long-range photographic and bombing missions. And those bombing missions, every couple of days, were important for keeping bypassed bases combat-ineffective after the initial carrier strikes.

          • bean says:

            Morison confirms that the Tarawa invasion was at least in large part done to get an airfield we could do surveillance of the Marshalls from. The Japanese locked them down in the aftermath of WWI, and we had no idea what sort of forces they had there.

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