INTERROGATION NAV NO. 37
USSBS NO. 159

ATTACKS ON JAPANESE SHIPPING

TOKYO 26 OCTOBER 1945

Interrogation of: Lt. Comdr. YATSUI, Noriteru, IJN; a naval officer of 8 years service. He was Navigation Officer of the cruiser Oi when she was sunk in July 1944 and served on the staff of the 7th Escort Convoy from that time until the end of the war.

Interrogated by: Captain Steadman Teller, USN.

SUMMARY

Lt. Comdr. YATSUI describes air attacks upon the resupply convoys to ORMOC in November 1944. He was present in the convoy which arrived at ORMOC on 31 October and lost one ship at anchor to U.S. Army horizontal-bombers the next day. He also was in the convoy arriving at ORMOC on 9 November. This convoy was attacked by U.S. Army B-25's and P-38's on entry, sustaining sufficient topside damage to interfere with unloading. The next day two cargo ships and one escort vessel were destroyed by a similar attack during the convoy's retirement. The complete destruction of a convoy and escorts by U.S. carrier-based aircraft off northwest LEYTE on 11 November is verified. An eye witness account is given of the U.S. carrier air attacks which destroyed most of an important tanker convoy at HONGKONG on 15-16 January 1945.

TRANSCRIPT

Q. Who was responsible for directing routing of Japanese merchant ships?
A. The commander of each individual Escort Convoy determined routes.

Q. Did he also determine the organization of convoy?
A. No, the commander of each individual Escort Convoy carried out his duties with ships assigned him. The organization of convoy was determined by the Commander in Chief, Grand Surface Escort Force (GEB).

Q. On what was the emphasis placed in your defense of convoys?
A. Some thought was given to AA, but the major factor was anti-submarine defense.

Q. What were the principal defense features? How were aircraft used? Were they used for cover and screening or for offensive search? Was radar used at night?
A. In general aircraft was used in two ways: first, as direct cover for the convoy; and second to carry out regular daily patrols over the entire route of the convoy. The former was carried out with carrier-based planes if carriers were included among the escort vessels, and by shore-based air whenever this was practicable. Carrier aircraft were used very infrequently. We never had more than four carriers which could be used in convoy operations. Therefore, this employment was very limited. An effort was made to use radar against submarines as widely as possible; but due to poor technical ability and poor equipment, it proved to be very ineffective. We had equipment to detect your radar, but none to interfere with it. Our direction finding equipment gave us bearing, accurate to about 10 degrees.

Q. Where was the most emphasis placed in convoy defenses?
A. I, personally, looked upon maneuverability of the convoy as the most important single item. I always tried to organize my convoys in formations which would permit the maximum evasion tactics.

Q. How much information did you receive of the position of our submarines?
A. We had pretty good statistical information. We were able to foretell from statistical data, where to expect enemy subs and could even foretell the characteristics of such submarine groups -- that is, whether they would be aggressive, daring, or otherwise. Prior to departure from port, we were given intelligence bulletins concerning submarines. We had much confidence in these, and relied heavily on them.

Q. From your recollection of your records and reports of ships sunk, what were the most serious losses during the period September 1944 to January 1945?
A. In my own opinion, the loss of fuel was the greatest blow to the country as a whole. I cannot say whether attacks against tankers or ships carrying oil in drums was more damaging, but the loss of aviation gasoline shipped in drums during the emergency transportation of November and December 1944 was a severe blow to us.

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Q. What experience did you have in escort of convoy?
A. I made two trips out of the homeland. First one from MOJI to SHANGHAI, MANILA and ORMOC on LEYTE. I made two round trips from MANILA to ORMOC. The second trip from MOJI destined for SINGAPORE ended in your carrier attack on HONGKONG 15-16 January 1945.

Q. What was the organization of the First Escort Fleet between September 1944 and January 1945?
A. The First Escort Force or Fleet had headquarters at TAKAO and consisted principally of four groups of escort vessels called the Fifth, Sixth, Seventh and Eighth Escort Convoys. There were no escort convoys numbers one to four. There were other escort vessels assigned to the First Escort Force or Fleet; but all important convoys were sailed in charge of one of the four Escort Convoys. I was Staff Officer of the Seventh Escort Convoy. The Escort Convoys are tactical units and have no particular area of responsibility.

Q. Describe the attack which you received at HONGKONG from U. S. Carrier-based planes.
A. The convoy was en route south and had reached a position east of HAINAN Island. At this point a message was received from Headquarters at TAKAO that another convoy had been attacked near SAIGON. This influenced the Headquarters of the First Escort Fleet at TAKAO to order my convoy to take shelter. The convoy was first anchored inside some islands to the south of HONGKONG, but later moved into HONGKONG Harbor arriving there the 13th. On the 14th, information was received that the U.S. Carrier Force was about 200 miles south of HONGKONG. I believe this information was obtained from radio direction finders. In preparation for the carrier air attack, by the 15th the convoy was disposed as follows: In HONGKONG Harbor, three large tankers moored to buoys in a small group south of HONGKONG Island and surrounded by nine escort vessels in a circle around the tankers. The tankers were moored in a position of a triangle, 300 meters on the side, and the escort vessels circle was about 300 meters outside the tankers. I was in the KANJU, flagship of the Seventh Escort Convoy, anchored in the eastern part of the circle. A fourth large tanker was moored east alongside dock of the ship-building yard at HONGKONG and was protected by two escorts off shore. The fifth tanker, which was the smallest, was moored at a KOWLOON dock approximately north of the main group of tankers and was unprotected. No air cover was available. All tankers were in water ballast hence there were no serious fires. Damage in the three or four attacks on 15 January was not serious. I estimate 4 or 5 planes were shot down. Thirty or forty casualties were suffered. There were no night attacks. On 16th the naval tanker Kamoi (northernmost of three tankers in the group) received 3 or 4 direct dive-bombing hits. She did not sink but was made useless. One other of this group received several hits and settled to bottom with deck above water. The third of this group also was hit heavily and became inoperative. The tanker alongside HONGKONG shipyard dock received several hits which though failing to sink her, completely disabled her. The Sarawak Maru, alongside KOWLOON wharf was not believed to have been attacked. Planes approached from a direction which possibly made her difficult to see. Although no escort vessels were sunk or put completely out of commission, casualties were high on them and some extensive material damage was sustained. I was hit by strafing at about 1430 and have been in hospital since. This was the heaviest attack and was sustained for about 15 minutes. I witnessed shooting down of about 12 or 13 planes. Later reports stated that about 20 total were shot down. The ships involved in this were:

Kamoi -- special Navy tanker 10,000 G. T. (disabled).
Tenei Maru -- tanker 10,000 G. T. (disabled or sunk).
Matsushima -- tanker 10,000 G. T. (disabled or sunk).
(name unknown) -- tanker 10,000 G. T. (disabled or sunk).
Sarawak Maru -- tanker 4,500 G. T. (undamaged).
Hatsuharu (DD) and 10 coast defense vessels-heavy casualties and some serious damage topside.

Q. When was first resupply convoy sent to ORMOC?
A. Don't know. But my convoy on 1 November was the second.

Q. Describe your experience in convoy which arrived ORMOC 31 October.
A. We arrived ORMOC in evening of 31 October and departed evening of 1 November. The convoy consisted of the Kashii Maru, Kinka Maru, Noto Maru and Kozu Maru -- all 10,000 tons plus. Was escorted by forces of Escort Convoy Fleet and DesRonOne. ComDesRonOne was in command. Total escort was 6 DDs, 4 coast defense ships. I had accompanied this convoy from JAPAN where it had loaded the crack First Division from the TOKYO Area. This division and its supplies was originally destined for MANILA but as the decision had been made to use every resource to defend LEYTE, the convoy proceeded to ORMOC. As this was a very important convoy we were supposed to have 10 fighters over head during daylight in PHILIPPINE waters and could call for 10

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more if needed. However, at times, there were none and never more than 15. The official arrangement for requesting air cover required that it be made by the convoy commander to the CinC Southwest Area Fleet (at MANILA). However, in sending the request by radio, it was intercepted by commanders of the local Naval Air Fleets who then used their judgment as to sending help. Army air units were not on this circuit and had to be reached through headquarters. I observed a number of engagements between Japanese Army fighters and P-38s. The Japanese fighters appeared to be badly outclassed. Route from MANILA was via VERDE Passage, SIBUYAN Sea, between BURIAS and TICAO Islands, TISAO Pass, then to the CAMOTES Sea and into ORMOC Bay, passing north of the CAMOTES Islands. A B-24 shadowed for 20 minutes off BURIAS Island. Off PALOMPON, LEYTE, about 30 sorties by P-38s were made about 2½ hours before sunset on the 31st. Planes strafed and dropped some small bombs. No serious damage was done to our ships. A few casualties and superficial damages to decks and guns were incurred. We arrived ORMOC just before sundown and had no further attacks that night. We anchored near and to west of ORMOC pier, about 1000 meters between ships. On 1 November shortly after dawn, P-38s commenced attacking and continued all day, both strafing and dive-bombing. No serious damage but quite a number of casualties to men on deck and material damage to guns and equipment on deck was sustained. At about 1400, three groups of 8 each of B-24s bombed from high level concentrating on the NATO Maru which was sunk at anchor. 90% of her cargo had been unloaded. No other ship was hit. All cargo was unloaded from other ships. U. S. plane losses consisted of 1 or 2 P-38s shot down by convoy guns on 31st and some additional shot down by Japanese fighters. No B-24s were observed shot down. The 3 remaining ships of the convoy and escort sailed from ORMOC at sunset 1 November and returned to MANILA without further incident.

Q. Describe your experience in the convoy to ORMOC on 10 November 1944.
A. I believe there were a total of nine ORMOC resupply convoys called TA operations. Number One occurred prior to 31 October; Number Two, which I accompanied, reached ORMOC on 31 October; Number Four, which I also accompanied, reached ORMOC 10 November; Number Three, however, occurred later than Number Four and was completely destroyed just before arriving ORMOC about 11 November. This convoy (Number Three) consisted of approximately 3 medium sized transports of 4,000/5,000 tons and 6 DDs. Its speed was 6½ to 7 knots. This convoy was destroyed by carrier-type planes. A message was received from this convoy stating that they were being attacked by 100 carrier-based planes. Possibly 1 DD survived. Number Four convoy consisting of Kashii Maru, Kinka Maru, Kozu Maru, DesRonOne and 4 coast defense vessels left MANILA on 7 November. It passed through TAYABAS Bay, MOMPOG Pass, MASBATE Pass, BLACK ROCK Pass, to the CAMOTES Sea and hugged the west coast of LEYTE very close. On the evening of the 9th as convoy rounded the southern tip of peninsula west of ORMOC, it was attacked and surprised by 20 or 30 B-25s and 15 or 16 P-38s which came out of hills from the north. The Kashii Maru had all loading tackle destroyed and landing barges on deck destroyed. The Kinka Maru suffered slight damage to engines and also suffered some damage to deck equipment. The Kozu Maru also suffered temporary engine trouble and deck damage. No important damage was done to escorts, but considerable casualties occurred. The main damage was done by bombs. Those bombs which struck the hull did not do enough damage to sink the ships -- the sea being calm at that time.

Arriving at ORMOC at dusk on the 9th, the convoy anchored just west of ORMOC Pier. There were no further attacks that night. At dawn on the 10th, P-38s arrived and harassed convoy all day, mostly strafing. It had been planned to discharge all cargo and personnel during the night and to leave at sunrise. Nothing could be unloaded at night and no cargo was unloaded because of the condition of deck equipment and lack of landing boats. An air raid two days before had destroyed landing barges on the beaches. However, all the Army troops, approximately 1 brigade, were put ashore by means of the coast defense vessels. The convoy departed about 3 hours after sunrise. About noon at southern tip of ORMOC Peninsula the convoy received same types of attack from 40 B-25s and 16 P-38s that was experienced on the 9th except this time we expected the attack. The Kozu Maru blew up and sank. The Kashii Maru received a bomb hit in bow which started a fire which finally stopped ship and caused it to sink several hours later. The Kinka Maru received minor damage and casualties and returned to MANILA. Coast Defense Ship No. 11 was beached at ORMOC Peninsula as result of bomb hit and fire. Four DDs and 1 coast defense ship stayed with Kashii Maru which was slowed and burning. Two DDs and two coast defense vessels accompanied Kinka Maru. About 1400 the Kinka Maru group, which stayed well out from shore, was attacked by 5 or more P-38s. One DD had bow blown off by bomb but was able to return to MANILA. Personnel casualties were suffered and very minor damages were incurred by other ships. The 4 DDs and 1 coast defense vessel, after Kashii Maru sank, followed and rejoined off MASBATE. The following returned to MANILA: Kinka Maru, 3 or 4 DDs and 3 coast defense vessels. In MASBATE Pass

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on night of 10 November, convoy Number Three passed them en route south. Two or three of DDs from DesRon One left the Kinka Maru and joined convoy Number Three. This convoy, as stated before, was sunk by carrier air off northwest LEYTE on 11 November.

Q. Were you attacked by motor torpedo boats in the PHILIPPINES?
A. On night of 31 October while anchored at ORMOC, motor torpedo boats were sighted near the easternmost COMOTE Island, but the defending destroyers prevented an attack.

Q. What was your experience in the cruiser Oi?
A. I was navigator on her when she was sunk at latitude 13N; longitude 114E, 19 July 1944. She was hit at 1230 Japan Central Time by one submarine torpedo on port side in after engine room. The ship sank in five hours due to flooding and the breaking of the ship at the point of damage in the high seas. The Oi had one DD in company which saved about 65% of her personnel.

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