Capt. Peter Heimstaedt, Shipwreck Discovery & Research Projects (SDRP), provided the following information and narrative. Peter's extensive research in the archives of the US and Japan, and interviews with the attackers and the survivors, undoubtably makes him "the expert" on the Attack of Coron Bay.

Information (After Action Report) provided by the Curator of the USS Lexington filled in details on the attack on the Kyokuzan Maru.

With apologies to Peter the original account was translated into American English and edited to include information from the after-action report of VB-19 which was also sent to Peter for his use.

The following is a detailed account on the Coron Bay air attack of 24 Sep 1944 gained from official U.S. Navy sources, U.S. Veterans Organizations, as well as the Japanese National Institute for Defense Studies Military History Department. By acknowledgement, this is the first recapitulation of the Coron Bay raid which has "meticulously accumulated pertinent facts and figures and, therefore, it is considered one of the most valuable contributions to the history of Japanese naval operations at the end of WW II."

Furnished with records and narrative descriptions from Roland Hanewald and Brian Homan, the first professional wreck divers in the Calamians, I started my research in 1992.

Thanks to the great support rendered by Gunter Bernert we both explored each known wreck to the maximum extent aiming at identifying the ships which had succumbed to bombs and gunfire 50 years ago. I spent much of my leisure time drawing sketches of the wrecks. In Manila I went to NAMRIA frequently to buy charts and ask for hydrographic statistics. In Tokyo I paid visits twice to express my gratitude for indispensable support. Back home in Germany, I studied hand-made expert line drawings to find out similarities of supply vessels of the Imperial Japanese Navy`s (IJN) Combined Fleet with the wrecks on the bottom of Coron Bay.

Before having unveiled the mysteries of "Olympia Maru" and "Taiei Maru" which was achieved in 1997 I terminated the 4-year long project and continued my research in Subic Bay together with Brian Homan. I probed the bottom of the sea at San Fernando (La Union) in search of the last Japanese trooper to leave the Philippines in 1945. And I spent almost a week at Santa Cruz (Zambales) to relocate the heavy cruiser "Kumano" which sunk near Hermana Mayor Island in 1944. Then, in 1998 I helped Henny Smits to explore the two Samal Island wrecks in front of the famous "Pearl Farm" beach resort in Mindanao. Today, I still hold the most complete documentation on WW II shipwrecks in the Philippines.

1. Task Group 38:

Let us start with the American side. The losses of the IJN at Coron Bay between 24 Sep and 9 Oct 1944 were caused by AG (Air Group) 18, AG 19 and AG 31. These were some of the U.S. Navies most successful air wings in the Pacific theater. AG 18 was commissioned at Alameda, Ca., on 20 July 1943. Originally, it was composed of 3 squadrons: Fighting 18 (VF 18), Bombing 18 (VB 18) and Torpedo 18 (VT 18). In Sep 1943 VF 18 was detached. At Hilo (Hawaii) in Feb 1944 VF 36 joined the Group and became VF 18, completing the Air Group`s complement.

AG 18 departed from Pearl Harbor on 15 Aug 1944 aboard U.S.S. Intrepid CV-11, AG 31 on U.S.S. Cabot CVL-28. In company of U.S.S. Enterprise CV-6 and various escorts they were to form Task Group TG 38.2.1. After 4 months of combat VF 18 was detached on 30 Nov 1944 at Ulithi. The remainder of the Group returned to the U.S. reaching Alameda on 20 Dec 1944 for reforming.

The standard tactical organization of the Fast Carrier Task Force was the TG (Task Group). Eventually, 2 CVs (fleet carriers) and 2 CVLs (light fleet carriers) operated with cruiser and destroyer escorts, but sometimes also with fast battleships. The Fast Carrier Task Force was composed of 4 Task Groups under the overall command of a Vice Admiral. Depending upon the fleet commander (Admiral Halsey with the 3rd fleet or Admiral Spruance with the 5th fleet) the carrier striking arm was designated TF (Task Force) 38 or TF 58. The ships of the Task Force remained the same but their designation changed whenever the fleet commander changed. This system allowed one Command Team to conduct an operation while the other Command Team planned and prepared for the next operation. It also acted as a ploy to confuse the Japanese. When the Fast Carrier Task Force (TF 38/58) was instituted in Jan 1944, the commanding officer was Vice Admiral Marc A. Mitscher. He remained in command, alternating the TF 38/58 designation, until fall 1944.

2. Combat Activities Aug/Sep 1944:

Arriving at Eniwetok Harbor on 24 Aug U.S.S. Bunker Hill (CVL-25) joined TG 38.2. On 6 Sep 1944 AG 18 launched its first fighter sweep and strike against the enemy at Palau.

From that time through 30 Sep, AG 18 attacked the following targets:
Davao, Mindanao
Matina, Mintal + Dalaio Fields, near Davao, Mindanao
Visayas: Leyte, Samar, Cebu, Negros
Peleliu (Air Support)
Anguar (Air Support)
Luzon: Clark Airfield, Manila Bay, Subic Bay, San Fernando (La Union)
Calamian Group: Coron Bay, Busuanga

3. Target Coron Bay:

On 23 Sep reports from Combat Air Patrol (CAP) missions revealed unusual enemy activities in the Calamian Island Group, south-west of Mindoro. AG 18 and AG 19 each received orders to equip 12 Curtiss SB2C-3 "Helldiver" bombers with wing tanks and to send them out on a fighter-bomber attack on Japanese shipping in and around Coron Bay. The planes from AG 18 were to carry two 500-pound bombs each. The planes of AG 19 carried a single 1,000 pound / 454 kg bomb. These "Helldivers" were the latest models already fitted with the APG-4 automatic low-level bombing system. In the dive bombing role these planes dove at their target until they had the ship centered in their Mark VIII gunsight and released their bomb(s) at 2,000 feet (600 m.) altitude. 96 F6F "Hellcat" fighters were ordered for this attack. Some were to provide fighter escort and some were armed with bombs to attack the shipping. As a "fighter bomber" the F6Fs would also dive on their target and center it in their gunsight before releasing their bomb. AG 31 was one of the units ordered to provide fighter escort. The sortie was to cover a chart distance of 350 miles. The aircraft were to fly completely across the Philippines from their carriers patrolling east of Leyte to Coron Bay, Palawan.

a. VB-18 of AG 18:

Mark Zalick led AG 18`s bomber group VB-18. Taking off at dawn, they surprised 15 Japanese ships in the Bay, the Coron Passage and just west of Coron Island. Ships ranged in size from small freighters to 15,000 ton tankers. Upon teaming up to take on the ships they were dispersed as follows (as Mark Zalick recalled):

i) between Tangat and Lusong Islands:
1 x destroyer (DD) or destroyer escort (DE);
2 x 10,000 ts supply ships (AG);
2 x 5,000 ts supply ships (AG);
3 medium-sized supply ships (AG).

ii) between Lusong and Lajo Islands:
2 destroyers (DD);
1 auxiliary oiler (AO);
1 gunboat (PG).

iii) west of Lajo Island:
2 destroyers (DD) or destroyer escorts (DE)

iv) in Coron Passage:
1 x 7,000-8,000 ts supply ship (AG)

v) west of Coron Island:
3 Subchasers (SC)

b. VB-19 of AG 19:

Commander R. McGowan led AG 19's bombing squadron VB 19 on this raid. Twelve SB2Cs took off but two had to return to the ship. One bomber had engine trouble and another had a fuel system malfunction and couldn't draw fuel from its' external wing tanks. Only 10 of the squadron's planes made the 332 mile flight to Busuanga Island.

Commander McGowan's after-action report stated, "Due to attacks already begun in Coron Bay, and orders from the leader of the entire strike from another air group, this flight attacked targets described herein."

TA-AK Single Stack of 10,000 to 12,000 tons
TB-AK 7,000 to 9,000 tons
TB-AK 7,000 to 9,000 tons

"The ten planes on this flight dived upon the three AK's described above. There is some doubt as to which planes attacked which targets, but more planes attacked the large single stack TA-AK than the other two. The three ships were almost line abreast in a small harbor on the north side of Busuanga Island in the northern part of the Calamian Group. The only photographic evidence available in the ship's photographs is a K20 picture which was taken from either the fifth or sixth plane to dive and does not therefore show all of the bomb hits."

"Interrogation reveals a hit on the port side of the single stack TA-AK, and there were three or more very near misses on this ship, and a fire started on the port side near the outer railing topside near the center of the ship. A very near miss while strafing in a dive also showed damage with a small fire to a TB-AK, also on the port side at about the same position. The hit upon the TA-AK was believed to be the bomb of Lieutenant L. R. Swanson."

Editor's Comment: The After Action Report of VB-19 states that due to difficulties with dropping their external fuel tanks which had previously been encountered they elected to dive on these ships while still carrying the external tanks. The tanks interfered with their ability to hit their targets, otherwise, there might be three wrecks down on the north side of Busuanga instead of just Kyokuzan Maru.

4. Japanese Plans and Movements:

Though COMTHIRD Fleet (Officer-in-command U.S. 3rd Fleet, Admiral William F. Halsey in the battleship U.S.S. New Jersey) characterized the enemies non-aggressive attitude as "unbelievable and fantastic", the Japanese were not surprised by the increasing American airborne strikes against Japanese installations in the Philippines. In August 1944 the Imperial General Headquarters (I.G.H.) had already decided that top priority in preparation for a "general decisive battle" along the inner defense line must be assigned to the Philippines.

For the Imperial Japanese Navy, the main value of the Philippines was for basing troops and staging ships, especially supply vessels which were essential units in providing replenishment for capital warships. However, main failure of the Combined Fleet`s command until September 1944 was to concentrate oilers, provision ships, salvage vessels and other auxiliary units in just a few "hot spots" in the Western Pacific. As "Operation Hailstorm" and the tragedy of Truk Lagoon in February 1944 clearly revealed, the Japanese had not understood the importance of a DOB (dispersed operating bases) policy.

It was only until the first American strikes on Palau in early September 1944 when Admiral Toyoda, Commander-in-Chief (C-in-C) of the Combined Fleet, realized that a fleet of almost 40 supply vessels had been anchored in Manila Bay or moored in Manila harbor. When TF 38.2 started their strikes against enemy shipping around Luzon in the second week of September, Japanese shipping in Manila harbor suffered severe damage, and numerous Japanese ships were sunk. Actually, Vice-Admiral Mikawa, commander of the Southwest Area Force in Manila, was not responsible for the supply vessels in Manila area due to the majority of the vessels operating under command of the Army. However, he advised Field Marshall Terauchi, commander of the Japanese Southern Army, that he recommended transferring all supply ships to Coron Bay which had served as a secure assembly place in the past. Terauchi was reluctant to make this decision. When he finally gave orders on 21/22 September 1944 to relocate the vessels he had already sacrificed 15 ships which were bombed and sunk in Manila Bay by repeated air strikes from TF 38.2.

5. Japanese vessels at Coron Bay:

According to official Japanese and American sources the following vessel movements are proven:

a. Kogyo Maru (Auxilliary Supply Ship, IJN/Navy)

After she had survived TF 38`s air attacks on Japanese shipping in Manila Bay and Harbor on 21 Sep 1944 she received sailing order to transfer to Coron Bay and weighed anchor at 1730 the same day. She arrived in Coron Bay on 23 Sep 1540 and dropped anchor in position 11deg; 58` 54"N / 120deg; 02` 15"E (GPS). The night was spent in trying to camouflage bridge and main deck. In the morning of 24 Sep at 0900 she was attacked by U.S. dive-bombers. After she had received several bomb hits the vessel sank with 39 men.

b. Okikawa Maru (Civilian oiler)

She had been mistaken for more than 50 years to be another tanker ship of very similar shape and size named Taiei Maru. She was in Manila Bay during the said air attacks. The ship got strafed but was not damaged. On 22 Sep she was ordered to move to Coron Bay and set sail at 1500. The vessel arrived in Coron Bay on 23 Sep 1800 and dropped anchor near the town of Concepcion. Okikawa Maru was attacked by 70 dive-bombers at 0855 on 24 September. The first two or more groups just strafed Okikawa Maru and continued to head for the seaplane tender Akitsushima anchored a few cables to the West. At 0910 the dive-bombers scored numerous hits and the vessel began to sink. Three gunners and 5 or 6 sailors were dead. The rest of the crew abandoned the ship. However, contrary to statements of Bowie and Dietrich (AG 31) Okikawa Maru did not sink at once. The forecastle remained afloat and burned until 9 Oct when another U.S. air group appeared and, in a final strike, send her to the bottom in position 12deg; 01` 10"N / 119deg; 58` 07"E (GPS).

c. Olympia Maru (Army cargo ship)

While laden with 1,250 tons rice and 500 cubic meters of supply materials for the Japanese occupation forces in the Philippines she had suffered one direct bomb hit while in Manila Bay on 21 Sep. When (Japanese) Southern Army Command received air warnings on a second attack the vessel was ordered to relocate to Coron Bay. She arrived on 23 Sep 1540 and dropped anchor just West of Tangat Island. On 24 Sep around 0900 about 40 dive bombers took on Olympia Maru after she had weighed anchor already and tried to evade the attacking planes. 10 aircraft attacked from starboard, then from port side. It was not until the third wave when the bombers scored direct hits to the engine room causing an explosion of the oil tank at port side (the vessel was diesel engined). Fire spread over the engine room when another bomb went through again. The engine stopped, another series of bombs hit the galley and cargo holds. At 1330 fire spread all over the ship bending the mid-ship section. At 1426 the ship sank from the stern in position 11deg; 58` 21"N / 120deg; 02` 39"E (GPS). 14 crewmen, 3 gunners and 2 passengers went down with the ship.

d. Taiei Maru?: (Army cargo ship)

Regretably, I still have no details on the history of this mysterious ship. To date there is no clue that this vessel was actually in Coron Bay at the time of TF 38`s attack. American sources still insist that two vessels with this name were sunk on 24 Sep 1944.

As I have found out, the oiler at Concepcion is not the Taiei Maru (Oiler) but actually Okikawa Maru. A quite modern civilian tanker of 9,929 gross tons named Taiei Maru and very similar to the older Okikawa Maru had been torpedoed already on 21 Aug 1944 by submarine USS Haddo in position 13deg 30`N by 120deg 15`E. Haddo attacked a Japanese convoy just after dawn at 6:00 a.m. She sank Kinryu Maru (4,392 gross tons) and Norfolk Maru (6,576 gross tons) and topedoed Taiei Maru, but was unable to observe the sinking of the latter. It is obvious that even the Japanese were confused over the multiple naming of their ships. Japanese auhorities have confirmed already since 1997 that the civilian oiler Taiei Maru never arrived in Manila. Therefore, it seems that Haddo also scored her as a victim.

With regard to its dimensions and tonnage I`m quite confident that the famous wreck lying on her starboard side close to the pearl farm was the former freighter Taiei Maru! If I were a dive operator at Coron I would have already removed the encrustation at the stern where everybody can see the letters "CEI...SH". Kawano-san told me that this could be the name of the vessel before being captured by Japanese troops. If somebody may reveal the entire name the Military History Dept. in Tokyo may probably find out more about this ship. By the way, it would be of interest to you that I have records on no less than six (6) vessels (freighters and tankers) which served the Imperial Japanese Armed Forces under the name Taiei Maru. If you wish to know each vessels' fate, please advise.

As you can see on every dive the vessel suffered from a series of direct hits in the bridge superstructure as well as into the hull. Obviously, she must have received some below-waterline hits on her starboard side causing a tremendous explosion of the engine-room which finally led to her sinking. She lies in position 11deg 59` 19"N / 120deg 02` 08"E (GPS).

Moreover, Ekkai Maru ex-Morazan Maru had been bombed and definitely sunk by TF 38 in Manila harbor on 22 Sep 1944. The reason why many want to be and self-made researchers still believe that Ekkai Maru was sunk in Coron Bay is very simple. According to the JANAC list she was lost in Coron Bay. The JANAC list was issued in 1947 when Japan was still devastated and Japanese naval experts willing to assist the Americans were not available. Most guys are using this source today as it is freely available, however, for serious researchers it has become obsolete and useless.

According to General Headquarters of the U.S. Military History Section the Ekkai Maru was sunk in Manila on 22 Sep 1944. This source was published after meticulous evaluation of the Imperial Japanese naval operations in WW II in 1952! The ship in Coron Bay is not the Ekkai Maru ex Morazon Maru.

e. IJNS Irako: (Navy Provision Store Ship/Reefer)

Allied type designator: AF

Irako had been underway from Japan to Takao (i.e. Kaohsiung/Taiwan today) when she was damaged on 12 Aug 1944 by unknown cause. Carrying a deck load of reconnaissance water planes she arrived in Coron Bay around 22 Sep 1944 and tried to hide her presence between Tangat and Lusong Island. On the morning of 24 Sep a number of fighter bombers of Airgroup 31 expended their bombs on the vessel. Their first strike scored direct hits into the midship section. Set ablaze on the bridge superstructure Irako began to sink over the bow. However, it took some time before she finally went down with considerable casualties.

Her final resting place is in position 11deg; 58` 10"N / 120deg; 02` 20"E (GPS).

f. IJNS Akitsushima: (Navy Seaplane Tender)

Allied type designator: AV

The vessel had suffered minor damage inflicted by U.S. air attacks near Buka Island on 1 Sep 1942 and received two direct bomb hits during "Operation Hailstorm" in Truk Lagoon on 17 Feb 1944. However, she remained afloat due to her very strong construction and state-of-the-art bulkhead design (just look at this point when diving the wreck next time). Criticism over the relatively long Japanese building times for special service vessels are, by the way, not justified. In comparison, allied ships of similar purpose stood little chance to survive bombings like these.

After being repaired in Japan she was back to service in July/August 1944. Akitsushima arrived in Coron Bay almost at same time as Irako and anchored in the narrow sound separating Lajo Island and Manglet Island. Strafed by Lt. (J.G.) Tuaspern and his wing she was first mistaken to be a destroyer escort (DE). VB-18 later scored one direct hit into the aft part of the vessel causing a tremendous explosion most likely of the AVGAS (aviation gasoline) fuel tanks for the flying boat.

She capsized within a few minutes and sank in position 11deg; 59` 20"N / 119deg; 58` 15"E (GPS).

g. IJNS Kamoi: (Navy Oiler / Special Seaplane Carrier)

Allied type designator: AO

Her previous history is still not known well enough. It seems that she arrived in Coron Bay in company of IJNS Akitsushima and anchored close to Lusong Island. On 24 Sep 1944 she was bombed by Airgroup 31. After being hit on the forecastle by Bowie and Dietrich (VF-31) she caught fire, but managed to escape by steaming southward. Seriously damaged and crippled, the vessel reached the open sea without being hit again. Steaming at dead slow speed she was torpedoed on 27 Sep by a U.S. submarine about 240 nautical miles south-west of Manila. Upon arrival at Hong Kong (on Oct 1944?) she was docked to undergo extensive repairs. There she was bombed repeatedly by U.S. naval aircraft on 5 and 7 April 1945 and finally ran aground.

h. Unidentified Supply Ships (2):

According to the After-Action Report of VF-31 there were two other auxiliary supply ships in Coron Bay area at the time of the attack. One was a ship of 4-5,000 gross tons at anchor just West of Lajo Island, the other was a vessel of 7-8,000 gross tons in the Coron Passage between Busuanga and uninhabited Coron Island heading eastward. The latter remained untouched while the other got strafed by Anderson-Duggin and McLaughlin-Arnold from VF-31 and was set aflame from stern to bow. As stated in the report she was believed sunk.

It would be useful to make test dives at the western tip of Lajo Island to find out whether another big ship lies there on the bottom or not.

i. Unidentified Submarine Chasers and Gun Boats (3):

When VF-31 teamed up to sink the Japanese ships in Coron Bay there were also three (3) subchasers (SC) patrolling West of Coron Island. The three ships were strafed by Kona, Free and Zimmerman and by another unidentified plane. Consequently, two of them sank. One might be the so-called "Skeleton Wreck" lying in shallow water at Balolo Point. The other was either never located or she was likely able to creep to Tangat Island where she finally ran aground in the passage between Tangat and Apo Island (see "East Tangat Wreck").

One gunboat was strafed by Wilson when cruising close to Concepcion village. Disabled by hundreds of machine-gun bullets she was beached at the southern tip of Lusong Island (see "Lusong Wreck").

j. Kyokuzan Maru: (Army Cargo Ship)

Peter's Comments: No detailed story available yet. Waiting for After-Action Report of AG-19. However, it is obvious that this vessel did not sink due to bombing as the hull, cargo holds as well as the engine room are still intact and the lifeboat davits have been swung out (note this point during your next dive). It is believed that the crew scuttled and abandoned the ship upon being discovered by U.S. dive bombers.

Editor's Comments: The After-Action report of VB-19 stated that they had at least one hit and numerous near misses on the largest of the three ships anchored here. Even with near misses, their 1,000 pound bombs may have ruptured the ships' hull plating inward and sunk her like the Titanic. Damage to the lowest plates just forward of the stern on the starboard side can be seen on diving the Kyokuzan Maru. This could be bomb damage or damage from striking the coral reef after sinking. Alternatively, there may be another ship sunk nearby with bomb and fire damage and this ship was actually scuttled. Personally, I can't see the same guys who could make suicide charges screaming "Banzai" scuttling an undamaged ship.

"By the way, this is my favorite wreck - by size, shape, condition and visibility! It is one of the most beautiful shipwrecks I have ever dived." Peter