In early 1942, the IJN’s carrier force was at its zenith. Since the start of the war, no carriers had been lost and losses of carrier aircraft had been relatively light. The Kido Butai had accomplished every mission it had been assigned and had smashed all Allied opposition before it. However, it had yet to meet the US Navy’s carrier force. In May 1942, the IJN’s carrier force held both a numerical and qualitative edge over its American counterpart. Six fleet carriers, Akagi, Kaga, the two ships of the Soryu class and the two units of the Shokaku class, remained at the center of Japanese naval air power. The light carriers Hosho, Ryujo and the two units of the Shoho class supported the fleet carriers. One escort carrier, Taiyo, was also in service. Adding to the numerical advantage of the IJN was the May 1942 completion of the converted carrier Junyo, capable of carrying some 50 aircraft. Had this force remained massed as it had been during the first part of the war, it would have retained a numerical edge in any battle with the US Navy’s carrier force. However, for the Coral Sea operation only three carriers would be committed.
The heart of the MO Operation was the two ships of the Shokaku class, which made up the Kido Butai’s Carrier Division 5. These ships were designed free of any naval treaty restrictions to specifications that called for a ship capable of operating a large air group while possessing high speed, good protection and a large radius of action. The result was the epitome of Japanese carrier design and the most powerful and best-balanced carrier design in the Pacific until the advent of the US Navy’s Essex class in 1943. The Shokaku was laid down in December 1937 and Zuikaku in May 1938 and both were barely completed and placed in service in time for the Pearl Harbor operation. The basis of the design was that of the preceding Hiryu class but with an additional 100ft in length and an approximate 8,500 extra tons of displacement. In spite of this increased size, the ships retained a very high speed owing to the fitting of the most powerful machinery ever on an IJN ship and a new bulbous bow that reduced underwater drag. Two hangars were provided and three elevators were installed to handle the large air group. A small island was placed forward on the starboard side.
Hiryu, shown here on sea trials in 1939, was the design basis for the larger and more successful Shokaku class. Hiryu and her sister ship Soryu formed Carrier Division 2 of the Kido Butai and were very active during the first part of the war. Neither ship was present at the Coral Sea, but both were committed to the Midway operation where they were sunk by American carrier air attack. (US Naval Historical Center)
In addition to their superb offensive capability, the Shokakus also carried a heavy defensive armament with eight Type 89 twin 5in. guns fitted in pairs, each with its own fire-control director. When commissioned, each ship also carried 12 25mm Type 96 triple mounts.
HIJMS Shokaku and Zuikaku
| Displacement: 26,675 tons | Aircraft capacity: 84 (72 operational) |
| Dimensions: length 845ft; beam 85ft; draft 29ft | Radius: 9,700 miles |
| Maximum speed: 34 knots | Crew: 1,800 |
Shoho was originally designed as a high-speed oiler, but was completed as a submarine tender. Her real purpose was to provide a ready-made basis for conversion into a light carrier. As war loomed, conversion of the Shoho began in January 1941 and was completed one year later. When Shoho joined the fleet with her sister ship Zuiho, they were the most successful of the Japanese light carrier conversions. The simple conversion required that the original diesel engines be removed and replaced by destroyer turbines. The flight deck was fitted over the existing structure and two elevators served a single hangar deck. No island was fitted with navigation being accomplished from a position forward of the hangar. When completed, the Shoho possessed adequate speed and a useful air group. However, the ship possessed no protection.
A fine view of Shoho on December 20, 1941. Note the lack of an island. Navigation was accomplished from a small bridge located under the forward part of the flight deck. (Yamato Museum)
A beam shot of Shoho showing the hull lines of her former identify as a submarine tender. The two starboard side dual 5in. guns can be made out as can the two triple 25mm mounts aft of the downward canted exhaust stack. (Yamato Museum)
Defensive armament included four Type 89 twin 5in. mounts. The short-range anti-aircraft fit originally consisted of an inadequate four triple 25mm mounts.
HIJMS Shoho
| Displacement: 11,262 tons | Aircraft capacity: 30 (27 operational) |
| Dimensions: length 712ft; beam 59ft; draft 22ft | Radius: 9,236 miles |
| Maximum speed: 28 knots | Crew: 785 |
Unlike on American carriers, no Japanese carrier began the war fitted with radar. This situation persisted until after the battle of Midway. This made the task of controlling defending fighters very difficult. In the early-war period, half of the 18-aircraft fighter squadron was dedicated for defense. With no radar, air defense was accomplished by conducting standing patrols. However, only a few aircraft (usually a section of three) would be airborne at any time with the remaining aircraft standing by to be scrambled if adequate warning was gained. Adding further difficulty to the fighter defense problem was the inferior quality of Japanese aircraft radios that made it virtually impossible to control aircraft already airborne.
Overall, the effectiveness of the IJN’s shipboard air defenses was inadequate throughout 1942, and this situation never really changed for the remainder of the war. Because Japanese shipboard anti-aircraft gunnery was unsuccessful in defending carriers from American air attack, the primary defense against air attack was mounted by fighters or by the ability of a carrier’s captain to maneuver skillfully under attack. When exposed to air attack, Japanese carrier escorts maneuvered independently to give the carrier maximum room for maneuver. In contrast, American carrier escorts also gave the carrier room for radical maneuvers, but were still expected to stay close enough to the carrier to provide anti-aircraft support
Japanese anti-aircraft weaponry and fire control did not compare favorably to that of the US Navy in early 1942. The standard 5in. antiaircraft weapon, the Type 89/40 was a respectable weapon, but its Type 94 fire-control director had difficulty tracking fast targets. Japanese 5in. gun crews were trained differently from their American counterparts. Unlike American crews, who practiced aimed fire, the Japanese crews were trained to use barrage fire. This may have been suitable against horizontal bombers forced to maintain a predictable course and speed, but it was ineffectual against more maneuverable carrier-based torpedo and dive-bombers. Since the Japanese never developed an effective intermediate-range, air-defense weapon during the war, the Type 96 25mm gun served in the intermediate and short-range roles. This weapon had many faults and even the Japanese recognized that it could not handle high-speed targets because it could not be trained or elevated fast enough by either hand or power and its sights were inadequate for high-speed targets. It also demonstrated excessive vibration and muzzle blast, and its magazines were too small to maintain high rates of fire. To add to the IJN’s troubles, even when the Type 96 managed to hit its target, its small weight of shell (0.6 pounds) was most often ineffective against the rugged American Dauntless dive-bomber. The Type 96 was first introduced as a double mount and in 1941 a triple mount was introduced. Overall, Japanese anti-aircraft gunnery was only a minor factor during the battle of the Coral Sea.
Even before the war, the primary mission of Japanese carriers was to sink their American counterparts. The events of the first few months of the war had only reinforced the necessity of gaining air superiority by eliminating the enemy’s carriers. Like the US Navy, the Japanese viewed their own carriers as vulnerable to attack. Like every other component of the IJN, Japanese carriers were designed and trained for offensive warfare. In the case of carrier combat, the essential precondition for victory was to find the enemy’s carriers first and launch overwhelming strikes as quickly as possible. Ideally, this would be done beyond the range at which the enemy could retaliate, explaining the great Japanese emphasis on large carrier air groups composed of aircraft uniformly lighter than their opponents, thus giving them greater range.
A strike preparing to launch from the carrier Shokaku. This shot was taken during the battle of Santa Cruz in October 1942, but it shows a typical deck spot for a strike launch. The most forward aircraft are A6M2 Type 0 carrier fighters; further aft are D3A1 Type 99 carrier bombers. (US Naval Historical Center)
One important advantage exercised by the Japanese at the start of the war was their ability to mass carrier air power. In April 1941, the Japanese brought all their fleet carriers into a single formation, the First Air Fleet. The Kido Butai (literally “mobile force” but better given as “striking force”) was the operational component of the First Air Fleet. Three carrier divisions made up the Kido Butai, including the Fifth with the newly completed Shokaku and Zuikaku. Unlike in the US Navy where the carrier division served only in an administrative capacity, the carrier divisions of the Kido Butai were operational entities. The two carriers of Carrier Division 5 fought as a single unit where squadrons of each carrier routinely trained and fought together. Typically, when multiple carrier operations were being conducted, the entire strike would be commanded by one of the carrier group commanders, who would direct the operations of the entire strike. Usually, the strike was accompanied by an escort of six to nine fighters from each carrier. Throughout 1942, including at the Coral Sea, the IJN was able to integrate operations from different carriers far better than the US Navy and routinely achieved a higher level of coordination.
Each Japanese carrier had its own air group. This air group was named after its parent ship and was permanently assigned to the ship. The aviators of the air group as well as all of the personnel required to support the aircraft were assigned to the ship’s company.
Shokaku-class carriers had air groups made up of three different types of flying units. These included fighter, carrier bomber (dive-bombers) and carrier attack (torpedo bomber) squadrons. Each of these squadron equivalents also retained the name of their parent carrier. At the start of the war, Shokaku-class carriers embarked 72 aircraft broken down into one 18-aircraft fighter squadron and two 27-aircraft carrier bomber and carrier attack units. Even with relatively light aircraft losses, by May 1942 the IJN was unable to provide the two ships of Carrier Division 5 with any more than approximately 63 aircraft. The fighter units on Shokaku and Zuikaku were up to strength, but the attack squadrons for both carriers were some 25 percent under strength. As a light carrier, Shoho embarked only two types of squadrons, fighter and carrier attack. The fact that even light aircraft losses were already taxing the IJN’s capability to provide replacements was again demonstrated by Shoho’s May 1942 air group. Her fighter squadron possessed only 12 aircraft, and of these four were the recently replaced A5M Type 96 fighters. Shoho’s carrier attack unit included only six aircraft. Altogether, Shoho embarked only 18 of her capacity of 27 aircraft.
Japanese carrier aircraft were designed for maximum range. This gave them an important edge over their American counterparts, but the penalty for this was reduced protection. The most dramatic example was the standard IJN carrier fighter, the A6M Type 0 (given the codename “Zero” by the Allies). Design specifications for this fighter were issued in 1937. The first variant, the A6M1, took to the air in April 1939. The A6M1 proved to be underpowered; with the provision of a larger 950hp engine, the A6M2 was born. In its day, the Type 0 fighter became a legend. While it was an inspired design that possessed exceptional maneuverability, great climb and acceleration, a relatively strong armament and unparalleled range for a fighter, it was not invincible. The Type 0 fighter’s performance was achieved only by lightening the airframe as much as possible. This meant that the aircraft possessed almost no armor and the pilot and fuel tanks were vulnerable to damage from even small-caliber weapons.
A Type 97 carrier attack plane recovering aboard Shokaku. At the start of the war, 27 aircraft were assigned to the carrier attack units of Shokaku and Zuikaku. By the Coral Sea, the squadron had shrunk to 20 aircraft. The Type 97 was a versatile aircraft able to perform torpedo and level bombing missions. (Yamato Museum)
Specifications for Mitsubishi A6M2 Type 0 carrier fighter plane Model 21
Crew: one
Armament: two 7.7mm machine guns and two 20mm cannon
Maximum speed: 336mph at 19,685ft
Range: 1,160 miles
Owing to the shortage of aircraft, Shoho’s fighter unit possessed a mixed unit of A6M and A5M fighters. The A5M (or “Claude” to Allied intelligence) was first delivered into fleet service in 1937 and was clearly outmoded in 1942 with its open cockpit, inferior speed and light armament.
Specifications for Mitsubishi A5M4 Type 96 carrier fighter plane Model 34
Crew: one
Armament: two 7.7mm machine guns
Maximum speed: 270mph at 9,845ft
Range: 746 miles
The Aichi D3A1 Type 99 Carrier Bomber was the IJN’s standard shipborne dive-bomber for the first half of the war. The markings of this Type 99 show it to be from Zuikaku. (Ships of the World Magazine)
The IJN called its dive-bombers “carrier bombers.” The standard carrier bomber at the start of the war was the D3A1 Type 99 carrier bomber. It was given the codename “Val” by the Allies. The provision of fixed landing gear gave the aircraft a dated appearance, but the Type 99 was a very effective dive-bomber designed to maintain a stable dive of up to 80 degrees to attain maximum accuracy. Overall, the Type 99 was not the equal of the American SBD Dauntless. It did not carry self-sealing fuel tanks, it lacked the ruggedness of the US dive-bomber, and it could not carry as heavy a payload as the Dauntless.
Close-up shot of the cockpit and the Type 91 air-launched torpedo carried aboard a Type 97 carrier attack plane. The combination of this relatively fast torpedo plane and an excellent torpedo provided the IJN with a superb ship-killing capability. (US Naval Historical Center)
Specifications for Aichi D3A1 Type 99 carrier bomber Model 11
Crew: two
Armament: one 551-pound centerline bomb; two 132-pound bombs under the wings; two forward-firing 7.7mm and one rear-firing 7.7mm machine gun
Maximum speed: 240mph at 9,845ft
Range: 915 miles
Rounding out the Japanese air groups were what the IJN called “carrier attack planes.” This aircraft possessed the capability to operate as a torpedo bomber or a horizontal bomber, depending on the target. By 1942, the standard carrier attack plane was the B5N2 Type 97 carrier attack plane (codenamed “Kate” by the Allies). The Type 97 was greatly superior to the standard US Navy torpedo bomber of early 1942 in key areas such as speed, climb and range. Increasing the edge enjoyed by the Japanese was the much greater reliability of Japanese torpedoes over their American counterparts. The rugged nature of Japanese torpedoes allowed them to be dropped from higher altitudes and at higher speeds. However, the Type 97 did possess the same weakness as other Japanese carrier aircraft with range and performance being achieved at the expense of protection.
Specifications for Nakajima B5N2 Type 97 carrier attack plane Model 12
Crew: three
Armament: one 1,764-pound torpedo or 1,764 pounds of bombs; one flexible rear-firing 7.7mm machine gun
Maximum speed: 235mph at 11,810ft
Range: 608 miles
The Pacific Fleet’s carrier force was untouched in the Pearl Harbor attack. Enterprise and Lexington were both in the area of Pearl Harbor, but very fortunately for the US Navy, were not actually in the harbor on December 7. Numerically, the US Navy had a fleet carrier force equal to the Japanese in 1942, but in terms of employment, aircraft capabilities and personnel training, the two opposing carrier forces were very different. The US Navy had been developing carrier aviation since the 1920s. By 1942, it was a large force with seven fleet carriers built around two main classes. Additionally, there were two unique carriers, Ranger and Wasp. Both were seen as inferior designs; Ranger was never committed to combat duty in the Pacific and Wasp arrived in the Pacific later in 1942 and was quickly sunk.
Ranger was the US Navy’s first attempt to design a fleet carrier from the keel up. Her design was considered a failure, but several of the features introduced were employed on the more successful Yorktown class. Ranger did not see combat action in the Pacific. (US Naval Historical Center)
Lexington in February 1933 pictured off the Hawaiian Islands. The ship’s battlecruiser lineage and the large stack aft of the small bridge are evident. The US Navy’s emphasis on embarking a large air group can be seen by the large numbers of aircraft spotted forward and aft on the flight deck. (US Naval Historical Center)
Entering service in 1928, the two ships of this class, Lexington and Saratoga, were the first true US Navy fleet carriers. As carriers converted from battlecruisers, they were large, displacing 36,000 tons. Their most salient feature was the huge smokestack on the starboard side located just behind the separate island. The island was small and contained gunnery and aircraft control as well as navigation facilities. Given their battlecruiser ancestry, both were very fast, but since they were the longest ships in the world at the time, they were not very maneuverable and took a while to answer the helm. The Lexington was the more modern of the two sisters since before the war she had had her bow widened expanding the size of the flight deck. In 1940, a CXAM air search radar was installed on the forward part of Lexington’s stack.
Lexington pictured prior to the war in October 1941. The 8in. gun mounts fitted fore and aft of the island and stack, originally fitted for protection against cruiser attack, remain aboard and would not be removed until April 1942. Her prewar air group includes Brewster F2A Buffalo fighters spotted forward, as well as Dauntless dive-bombers and Devastator torpedo aircraft spotted amidships and aft. The Devastators can be distinguished by their folding wings. (US Naval Historical Center)
For anti-aircraft protection, 12 single 5in./25 gun mounts were positioned on sponsons on the corners of the flight deck. To counter the threat of dive-bombing, both ships carried a large battery of automatic weapons. Beginning in 1940, 1.1in. quadruple machine-cannons were installed. Five of these weapons were fitted, reducing the number of single .50-cal. machine guns to 28. The outbreak of war saw further augmentation of the anti-aircraft battery. Lexington had her 8in. guns removed in April 1942. At Coral Sea, she mounted a total of 12 quadruple 1.1in. mounts, 32 20mm guns and 28 machine guns.
USS Lexington
| Displacement: 36,000 tons | Aircraft capacity: 90 |
| Dimensions: length 888ft; beam 105ft; draft 32ft | Radius: 6,960 miles |
| Maximum speed: 34kts | Crew: 2,122 (pre-war) |
The three ships of the Yorktown class were the first truly modern US Navy fleet carriers and proved so successful they formed the basis for the even more successful Essex design. Generally an improved Ranger design, these 20,000-ton ships were large enough to permit the incorporation of protection against torpedo attack. A four-inch side armor belt was fitted over the machinery spaces, magazines and gasoline storage tanks. Vertical protection was limited to 1.5in. of armor over the machinery spaces. The main deck was the hangar deck with the unarmored flight deck being built of light steel. The primary design focus of the class was to provide adequate space to operate a large air group. To support the air group quickly and efficiently, three deck elevators were fitted to move aircraft between the hangar and flight decks and the large hangar deck was serviced by large roller curtains which could be opened to allow aircraft to warm up prior to launch, thus speeding flight operations. The large island was fitted with spaces for conning and navigation, control of aircraft and fire control for defensive weapons.
The Yorktown class also received a heavy defensive battery to counter enemy air attack. This class was among the first US Navy ships equipped with the new 5in./38 dual-purpose guns, which proved to be the best long-range anti-aircraft weapon of the war in any navy. The eight 5in./38 guns were controlled by a pair of Mark 33 directors mounted on the island. For intermediate and close-in protection, four 1.1in. quadruple mounts were placed fore and aft of the island and a total of 24 .50-cal. machine guns were fitted on the gallery deck. Before the battle of the Coral Sea, Yorktown had received 20mm single mounts in place of the ineffective .50-cal. weapons. Another important improvement was the addition of radar. Yorktown was one of the ships to receive one of the first six CXAM sets in October 1940. CXAM was an air search radar that used a very large mattress-like antenna. Increases in power, and therefore detection ranges, led to the introduction of the CXAM-1 radar. With an accuracy of 200yds, it was capable of detecting a large aircraft or aircraft formation flying at 10,000 feet at 70 nautical miles or a small aircraft at 50 nautical miles.
Yorktown pictured in 1937 just after commissioning. She was the lead ship in the US Navy’s first class of modern carriers. Besides rendering outstanding wartime service, the Yorktown class provided the design basis for the even more successful Essex class. (US Naval Historical Center)
USS Yorktown
| Displacement: 19,576 tons | Aircraft capacity: 81 |
| Dimensions: length 810ft; beam 110ft; draft 25ft | Radius: 11,200 miles at 15 knots |
| Maximum speed: 33kts | Crew (1941): 227 Officers, 1,990 enlisted personnel (including air group) |
Prior to the war, the US Navy viewed its aircraft carriers as vulnerable, reflecting the belief that carriers could not withstand significant damage. This notion drove US carrier designers to achieve maximum offensive potential in the hopes that a quick strike would remove the enemy carrier threat. This also drove prewar carrier doctrine that carriers should be separated in the hope that they would avoid simultaneous detection and destruction. By April 1942, with the benefit of limited war experience, carrier air defense remained a weakness. However, the US Navy had the great advantage of possessing radar. This carried the promise that an effective fleet air defense could be mounted as now approaching enemy aircraft could be detected well beyond visual range and defending fighters could be sent out to intercept the intruders at a distance from friendly carriers. However, in early 1942, this was only a theoretical advantage as radar fighter direction was in its early stages. Communication problems and the inability of early radar to give reliable altitudes, combined with a general lack of experience, would greatly complicate fighter direction.
Typically, half of a carrier’s fighters would be retained for fleet air defense. These were used to mount standing combat air patrols (CAP) of two to three hours’ duration during daylight hours above the carrier. The remaining fighters would be fueled and armed on deck ready for launch to augment the existing patrols. Some carriers (including Yorktown and Lexington) had the doctrine of augmenting their CAP with Dauntless dive-bombers assigned to anti-torpedo plane patrol. These were conducted at low altitudes in the immediate area of the home carrier in an effort to augment defenses against low-flying and relatively slow torpedo planes.
Augmenting the defensive efforts of the carrier’s air group were the antiaircraft guns aboard the carrier and its escorts. The American long-range air defense gun during 1942 was the 5in. dual-purpose gun. The unrivaled 5in./38 gun was mounted aboard Yorktown and the escorting destroyers. It was an accurate gun and, most importantly for anti-aircraft use, had a high rate of fire. A well-drilled crew could get off 20 rounds per minute out to a maximum of 18,200yds. The older 5in./25 gun aboard Lexington and the escorting cruisers was still a capable weapon, but possessed a shorter range of 14,500yds. These weapons used fire-control directors or local control to engage individual targets or were used to place a barrage in front of attacking enemy aircraft.
The heavy cruiser Portland saw extensive service as a carrier escort in the early parts of the war. She would be assigned to screen Yorktown at both the Coral Sea and Midway. (US Naval Historical Center)
Intermediate and short-range anti-aircraft protection was provided by a mix of guns. During early 1942, intermediate defense was provided by the 1.1in. machine cannon. This was a four-barreled, water-cooled system that could deliver a rate of fire of 140 rounds per minute per barrel. However, in service it proved disappointing owing to continual jamming problems. Last-ditch air defense was provided by the remaining .50-cal. machine guns and the 20mm Oerlikon gun, which was being mounted in increasing numbers aboard American carriers and other ships throughout 1942. Since the weapon was lightweight and required no external power source, it could be mounted anywhere with a clear arc of fire. Aiming was performed through a ring site and fire spotted through the use of tracers. However, with an effective range of 2,000yds or less, these short-ranged weapons had two critical disadvantages. In general, only the ship being attacked could use them and when a target was engaged, it had likely already dropped its weapon. Gunnery against aerial targets was given a high priority and American gunners incessantly trained with their weapons. However, by May 1942 American anti-aircraft gunnery was limited to inflicting relatively minor losses on attacking Japanese aircraft.
The standard 5in. gun aboard all US heavy cruisers at the Coral Sea was the 5in. /25 gun. This is the Number 3 mount aboard heavy cruiser Astoria. (US Naval Historical Center)
The port side forward battery of 20mm Oerlikon guns on Yorktown. Early in the war, the 20mm proliferated throughout the fleet as a replacement for the ineffective .50-cal. machine gun. The 20mm could be deployed anywhere with a clear arc of fire by simply bolting the weapon to the deck. Though an improvement over the .50-cal. machine gun, it still lacked the range to engage enemy aircraft before they had an opportunity to drop their weapons. (US Naval Historical Center)
Early 1942 American carrier strike doctrine was less mature than that practiced by the IJN. Typically, in the morning, a number of dive-bombers would be launched to perform reconnaissance. If a target was located, a strike was launched as soon as possible with every available dive-bomber and torpedo plane. The fighter squadron was usually divided with half providing strike escort and the other half providing CAP. The problem with US Navy strike doctrine was that it remained focused on the operations of a single air group from a single carrier. While the Japanese had made the mental leap to mass all their fleet carriers into a single unit and could operate aircraft from multiple carriers as a single entity in combat, the US Navy maintained the practice of forming a task force around a single carrier which in turn meant that strikes were conducted by single air groups. Ideally, the dive-bombers and torpedo bombers would conduct a coordinated strike against a high-value target (like an enemy carrier). By attacking together, they would split the target’s defenses which was an important factor given the potential vulnerability of the torpedo planes. However, serious problems existed in coordinating strikes even within air groups and coordinating strikes from different carriers was virtually impossible.
Complicating the task of American carriers was the fact that the ranges of their aircraft were inferior to that of the Japanese. The scout squadrons were usually charged to conduct scouting missions. These were conducted in the morning and afternoon out to a usual range of 150–200 miles. In this role they retained a 500-pound bomb to strike anything they found. Strike missions were conducted by both the scout and dive-bomber squadrons. In the strike role, the Dauntless dive-bomber had a doctrinal strike radius of 225 miles with a 500-pound bomb and 175 miles with a full 1,000-pound bomb load. Torpedo bombers were limited to a range of 150 miles with a full torpedo load. The strike range of escorting fighters was limited to that of the torpedo bombers since no auxiliary fuel tanks were used at this point of the war.
US Navy 1942 air groups were composed of four squadrons. The fighter squadron was equipped with 18 F4F Wildcat fighters. Two squadrons were equipped with the Douglas SBD-2/3 Dauntless dive-bomber. One squadron was named a scouting squadron and the second a bombing squadron, though in practice both squadrons performed virtually identically. Dive-bombing squadrons possessed between 16–21 aircraft. The air group commander usually was assigned his own dive-bomber. The torpedo squadron was assigned 12–18 TBD Devastator aircraft. Each TBD could carry a single torpedo or carry bombs and act as horizontal bombers. In the early war period, US Navy carriers each had a permanently assigned air group. Each of the assigned squadrons carried the hull number of the ship it was assigned to. For example, Lexington’s fighter squadron was numbered VF-2, her dive-bombers VB-2, her scout bombers VS-2 and her torpedo squadron VT-2.
Grumman F4F-3A Wildcats of VF-3 pictured in April 1942. Both of the aircraft pictured were later assigned to VF-2 during the battle of the Coral Sea and were lost. The Wildcat’s first meeting with the Japanese A6M Type 0 carrier fighter at the Coral Sea showed the American fighter to be outclassed, but American pilots were able to overcome the Wildcat’s weaknesses with better tactics. (US Naval Historical Center)
Dauntless dive-bombers of Yorktown’s Bombing Squadron Five shown on deck in April 1942. The Dauntless dive-bomber was the primary offensive weapon of US Navy carrier air groups, as events during the battle of the Coral Sea would demonstrate. (US Naval Historical Center)
The standard US Navy ship-borne fighter during 1942 was the F4F “Wildcat.” This was a modern design first flown in 1937. The version in service during Coral Sea was the F4F-4. The F4F-4 was introduced into the Pacific Fleet in April 1942 and featured several important differences including folding wings, six guns (vice four on the F4F-3) and factory-installed armor and self-sealing fuel tanks. All of these changes affected the aircraft’s climb and maneuverability. The Wildcat was no match for the Japanese “Zero” carrier-based fighter, but Wildcat pilots compensated for inferior aircraft with excellent gunnery skills against airborne targets and superior tactics.
Specifications for Grumman F4F-4 Wildcat carrier fighter
Crew: one
Armament: six wing-mounted .50-cal. machine guns
Maximum speed: 318mph at 19,400ft
Combat radius: 175 miles
The backbone of US carrier air groups was its two dive-bomber squadrons equipped with the Douglas SBD “Dauntless” dive-bomber. During a time when American carrier torpedo aircraft lacked an effective torpedo, the Dauntless constituted the striking power of the US Navy’s carrier air groups. It was accepted into service in 1939. By 1942, the SDB-3 was the primary model in service, and it mounted a dual machine gun for the rear gunner and carried improved armor and self-sealing fuel tanks. The Dauntless was a rugged aircraft able to absorb considerable combat damage, but it was most famous for being a stable and accurate bombing platform. Its only drawbacks were a mediocre top speed and non-folding wings that made movement and storage on carrier hangar and flight decks more difficult.
Specifications for Douglas SDB-3 Dauntless carrier dive-bomber
Crew: two
Armament: 1,600 pounds of bombs with another 650 pounds under wings; two cowl-mounted .50-cal. machine guns and two flexible .30-cal. rear-mounted machine guns
Maximum speed: 255mph at 14,000ft
Combat radius: 225 miles, depending on bomb load
Rounding out American carrier air groups was the TBD “Devastator.” This aircraft dated back to 1937, and while it constituted a major advancement for its day, by 1941 it was clearly obsolescent. The primary shortcoming of the Devastator was its slow speed and short combat radius. To top things off, the US Navy’s aerial torpedo, the Mark XIII, was notoriously unreliable and could not be dropped above 100mph or above 120 feet, which made the Devastator exceedingly vulnerable.
Specifications for Douglas TBD-1 Devastator torpedo bomber
Crew: three
Armament: one torpedo or 1,000 pounds of bombs; one .30- or .50-cal. nose-mounted machine gun and one .30-cal. flexible rear-mounted machine gun
Maximum speed: 206mph at 8,000ft
Combat Radius: 150 miles with ordnance
Perhaps the most important American advantage in the naval battles of early 1942 was in the arena of operational intelligence. In addition to the traditional means of traffic analysis of IJN radio messages (which provided insights into subordination, order of battle and operational tempo), the Americans had an even more valuable source of radio intelligence. The Americans had been making steady progress in cracking the IJN code in use since the start of the war. This code, known to the Americans as JN-25B, employed a double, and later a triple cipher system. By March 1942, the Americans had made enough progress on breaking the internals of the system to start piecing together parts of messages. By April, real advances had been made against JN-25B, which allowed up to 85 percent of some signals to be read. This effort was made possible by the delay in a scheduled IJN code change that was pushed back from April 1 to May 1, and finally June 1. The importance of this breakthrough was demonstrated when, on April 9, Nimitz received the first indication by signals intelligence that a Japanese move into the South Pacific was likely. Eventually, signals intelligence would discern the target of the Japanese operation and provide a very close idea of the forces to be committed to it. However, despite many claims to the contrary, radio intelligence was not a decisive factor during the 1942 battles of the Coral Sea and Midway. However, for the outnumbered US Navy, it was an invaluable tool since it allowed Nimitz to position his forces with the best likelihood for success.
(Vice Admiral Inoue Shigeyoshi (Commander, 4th Fleet) aboard light cruiser Kashima in Rabaul)
| MO Carrier Striking Force (Vice Admiral Takagi Takeo) * | |
| Carrier Division 5 (Rear Admiral Hara Tadaichi) | |
| Carrier Shokaku (Captain Jojima Takaji) | |
| Shokaku Air Group (Lieutenant-Commander Takahashi Kakuichi) | one D3A1 |
| Shokaku Carrier Fighter Unit | 18 A6M2 |
| Shokaku Carrier Bomber Unit | 20 D3A1 |
| Shokaku Carrier Attack Unit | 19 B5N2 |
| Total | 58 (56 operational) |
(plus another three A6M2 for Tainan Air Group in Rabaul)
| Carrier Zuikaku (Captain Yokogawa Ichihei) | |
| Zuikaku Air Group (Lieutenant-Commander Shimazaki Shigekazu) | one B5N2* |
| Zuikaku Carrier Fighter Unit | 20 A6M2 |
| Zuikaku Carrier Bomber Unit | 22 D3A1 |
| Zuikaku Carrier Attack Unit | 20 B5N2 |
| Total | 63 (53 operational) |
(plus another five A6M2 for Tainan Air Group in Rabaul)
Cruiser Division 5
Heavy cruisers Myoko, Haguro
Destroyer Division 7
Destroyers Ushio, Akebono
Destroyer Division 27
Destroyers Ariake, Yugure, Shiratsuyu, Shigure
Oiler Toho Maru
| MO Main Force (Rear Admiral Goto Aritomo) * | |
| Light carrier Shoho (Captain Izawa Ishinosuke) | |
| Shoho Air Group (Lieutenant Notomi Kenjiro)* | |
| Shoho Carrier Fighter Unit | eight A6M2, four A5M2 |
| Shoho Carrier Attack Unit | six B5N2 |
| Total | 18 (18 operational) |
| Cruiser Division 6 | |
| Heavy cruisers Aoba, Kako, Kinugasa, Furutaka | |
| Destroyer Sazanami (from Destroyer Division 7) |
MO Invasion Force (Rear Admiral Kajioka Sadamichi)
Destroyer Flotilla 6
Light cruiser Yubari
Destroyer Squadron 29
Destroyers Oite, Asanagi
Destroyer Squadron 30
Destroyers Mutsuki, Mochizuki, Yayoi
Destroyer Squadron 23
Destroyer Uzuki
Minelayer Tsugaru
Fleet minesweeper Number 20
Navy transports: Goyo Maru, Akihasan Maru, Shokai Maru, Chowa Maru, Mogamikawa Maru
Ocean tug Oshima
Army transports: Matsue Maru, Taifuku Maru, Mito Maru, China Maru, Nichibi Maru, Asakasan Maru carrying bulk of 3rd Kure Special Naval landing Force, 10th Establishment Unit, (construction troops) and 144th Infantry Regiment (South Seas Detachment)
Covering Force (Rear Admiral Marumo Kuninori)
Cruiser Division 18
Light cruisers Tatsuta, Tenryu
Seaplane carrier Kamikawa Maru (with air group from Kiyokawa Maru) 5th Gunboat Squadron
Specially fitted gunboats Nikkai Maru, Keijo Maru
Transport Shoei Maru carrying elements of 3rd Kure Special Naval Landing Force
14th Minesweeper Flotilla
Hagoromo Maru, Noshiro Maru Number 2 (from Tulagi Invasion Force May 3)
Tulagi Invasion Force (Rear Admiral Shima Kiyohide)
Minelayer Okinoshima
23rd Destroyer Squadron
Destroyers Kikuzuki, Yuzuki
14th Minesweeper Flotilla
Tama Maru, Hagoromo Maru, Noshiro Maru Number 2 (moved to MO Covering Force May 3)
Special Minesweeper Number 1, Special Minesweeper Number 2
56th Submarine Chaser Squadron
Patrol boats Tama Maru Number 8, Toshi Maru Number 3
Transports Azumayama Maru and Koei Maru carrying elements of 3rd Kure Special
Naval Landing Force and 7th Establishment Unit (construction troops)
Supply units
Oilers Ishiro, Hoyo Maru
Raiding Force
21st Submarine Squadron
Submarines RO-33, RO-34
Land-based Air Force **
25th Air Flotilla, 5th Air Attack Force (Rear Admiral Yamada Sadayoshi at Rabaul)
28 A6M2 fighters (18 operational)
11 A5M2 fighters (six operational)
28 G4M land-based bombers (17 operational)
26 G3M land-based bombers (25 operational)
16 H6K4flying boats (12 operational)
Fighters based at Lae, New Guinea and Launai Airfield at Rabaul. Bombers based at Vunakanau Airfileld at Rabaul. Flying boats initially based at Rabaul; later moved to Shortland and Tulagi Islands
*Strengths shown for evening, May 6, 1942
**Strengths shown for May 1, 1942
(Rear Admiral Frank Jack Fletcher)
| Carrier Group Task Group 17.5 (Rear Admiral Aubrey Fitch) | |
| Lexington (Captain Frederick Sherman) | |
| Lexington Air Group (Commander William Ault) | one SBD-3* |
| Fighting Two (VF-2) | 21 F4F-3 |
| Bombing Two (VB-2) | 18 SBD-2/3 |
| Scouting Two (VS-2) | 17 SBD-3 |
| Torpedo Two (VT-2) | 13 TBD-1 |
| Total | 70 (66 operational) |
| Yorktown (Captain Elliott Buckmaster) | |
| Yorktown Air Group (Lieutenant Commander Oscar Pederson)* | |
| Fighting Forty-two (VF-42) | 17 F4F-3 |
| Bombing Five (VB-5) | 18 SBD-3 |
| Scouting Five (VS-5) | 17 SBD-3 |
| Torpedo Five (VT-5) | 12 TBD-1 |
| Total | 64 (62 operational) |
| Destroyer screen | |
| Destroyers Morris, Anderson, Hammann, Russell |
Attack Group Task Group 17.2 (Rear Admiral Thomas Kinkaid)
Heavy cruisers Minneapolis, New Orleans, Astoria, Chester, Portland
Destroyers Phelps, Dewey, Farragut, (attached to TG-17.3, May 7), Alywin, Monaghan
Support Group Task Group 17.3 (Rear Admiral J. G. Crace, Royal Navy)**
Cruisers HMAS Australia, HMAS Hobart, Chicago
Destroyers Perkins, Walke
Fueling Group Task Group 17.6 (Captain John Phillips)
Oilers Neosho, Tippecanoe
Destroyers Sims, Worden
Search Group Task Force 17.9 (Commander George DeBaun)
Seaplane Tender Tangier (located at Noumea) with 12 PBY-5 Catalina flying boats from patrol squadrons VP-71, VP-72
Task Force 42 Eastern Australia Submarine Group (Rear Admiral Francis Rockwell) (under Southwest Pacific Area command)
TG-42.1 in submarine tender Griffin located at Brisbane
Submarine Division 53
S-42, S-43, S-44, S-45, S-46, S-47
Submarine Division 201
S-37, S-38, S-39, S-40, S-41
Of these boats, only S-38, S-42, S-44 and S-47 were able to go to sea before the battle began
Allied Air Forces (Lieutenant-General George Brett, United States Army) under command of Southwest Pacific Area ***
Fighter groups
8th Pursuit Group; two squadrons at Port Moresby equipped with P-400 Airacobras.
Total strength of group approximately 100 aircraft (full strength)
35th Pursuit Group located at Mascot Airfield, Sydney, equipped with P-39.
Total strength of group approximately 100 aircraft (full strength)
49th Pursuit Group located at Port Darwin equipped with approximately 90 P-40
Bomber groups
3rd Bombardment Group (Light) (located at Charters Towers)
8th Light Squadron (19 assigned A-24 (USAAF version of SBD Dauntless))
13th Light Squadron (assigned 19 former Dutch B-25)
19th Light Squadron (assigned 14 A-20)
22nd Bombardment Group (Medium) (Townsville)
Full strength with 80 B-26 and 12 B-25
19th Bombardment Group (Heavy) (Cloncurry)
48 B-17
Royal Australian Air Force
11th and 12th Squadrons equipped with PBY Catalina; both at half-strength (total six aircraft). Stationed on Tulagi until May 2
32nd General Reconnaissance Bomber Squadron equipped with Hudsons.
75th Squadron equipped with P-40 and stationed at Port Moresby. Strength on April 30 was three operational aircraft.
All four squadrons totaled 30 operational aircraft at start of battle
* Aircraft strengths as of dawn May 7
** This is the organization as of 0700 May 6, 1942. Previously, TF-17 was composed of Yorktown, heavy cruisers Astoria, Chester and Portland and the four destroyers assigned to TG-17.5. TF-11 included Lexington, heavy cruisers New Orleans and Minneapolis and the five destroyers assigned to TG-17.2. During the battle, TG-17.2 never operated as an independent entity. TG-17.3 was the renamed TF-44 from Southwest Pacific Area.
*** Aircraft strengths as of May 1