© 1998 Allyn D. Nevitt

Who Sank the Triton?

Submarine USS TRITON (SS-201), Lieutenant Commander G. K. MacKenzie, Jr., commanding, went missing in action in the South Pacific in March 1943. Most accounts of the loss state with some finality that TRITON fell victim to three Japanese destroyers (about whose presence she had been warned two days previous) in a depth charge attack north of the Admiralty Islands on 15 March 1943. The document "U.S. Submarine Losses World War II," issued by the Naval History Division, Office of the Chief of Naval Operations, states that this was the case "without a doubt.....Enemy reports show that these ships made an attack on 15 March at 0-09 N, 144-55 E.....The report of the attack by the destroyers leaves little doubt as to whether a kill was made, since they saw 'a great quantity of oil, pieces of wood, corks and manufactured goods bearing the mark Made in U.S.A.'" Such other gifted and well-known chroniclers of U.S. submarine operations as Theodore Roscoe and W. J. Holmes, apparently using this document as their basis, have also repeated its conclusions, the latter very authoritatively summing up that, "These three destroyers were responsible for the loss of TRITON."

The obvious question asked by this author is, "Just which Japanese destroyers were these that sank the TRITON?"

There is, to begin with, one very persuasive choice. The single Japanese naval movement most pertinent to this study would seem to have been the troop convoy designated Hansa No. 1, comprising six transports lifting units of the Imperial army's 20th Division to Hansa Bay (near Madang) in Eastern New Guinea. In escort were five destroyers -- KAZAGUMO, YUGUMO, AKIGUMO, SAMIDARE, and SATSUKI -- under Captain Yoshimura Matake, Comdesdiv 10 in KAZAGUMO. This convoy cleared Palau on 6 March 1943 and steered south for New Guinea.

On the first morning out, 7 March, SAMIDARE attacked an enemy sub and held it down for over an hour while the convoy passed, but made no claim on it. No further submarine contacts developed until the 11th, when SATSUKI dropped a half-dozen depth charges on a suspected sub with "results unknown." It should be noted that this was the same date that TRITON reported that she was indeed pursuing a convoy -- "Two groups of smokes, five or more ships each, plus escorts.....Am chasing" -- the last signal ever received from her. Might SATSUKI's attack have knocked out TRITON's communications gear -- or worse?

In any event, the convoy continued on to reach Hansa Bay unscathed the following day. The troopships were quickly unloaded and ready to head back to sea on 13 March. It's primary mission accomplished, the escort force split up at this time. Captain Yoshimura, with orders to proceed to Rabaul for Solomons transport duty, got underway first with KAZAGUMO, YUGUMO and SATSUKI. AKIGUMO and SAMIDARE were left behind to shepherd the empty merchantmen back to Palau.

Even as the latter departed from Hansa Bay they were struck by U.S. aircraft, which sank MOMOYAMA MARU. Did these same aircraft also spot the departing Yoshimura? Again quoting from the official report, "On the morning of 13 March TRITON was told that three enemy destroyers had been sighted at 2-00 S, 145-44 E on a northerly course. She was informed that they were probably on a submarine hunt or were a convoy cover and had missed contact."

Certainly, Yoshimura's three destroyers were heading in TRITON's general direction. And, being out in front, they would have swept the convoy's proposed track on antisubmarine alert as far north as was practicable. But they then swung sharply east for Rabaul, where all arrived on the 14th -- the day BEFORE the alleged fatal depth charge attack on TRITON. And none of the three, as far as can be determined, reported any encounters with submarines en route.

Note here that both the account of this convoy in Senshi sosho (or BKS, the official Japanese war history), v. 96, p. 72, and the individual ships' Tabular Records of Movement (or TROMs), have been examined. YUGUMO's TROM is admittedly not available for checking, but the others could have been expected to note her sinking of a sub had this taken place. For example, the TROM of destroyer HAMAKAZE for 10 January 1943 records the teaming of MAIKAZE and ISOKAZE against USS ARGONAUT (SS-166/APS-1) near Rabaul, even though HAMAKAZE herself was only an observer. And the BKS account of this January convoy (v. 83, p. 487) also relates ARGONAUT's sinking.

To close out Hansa No. 1: the five surviving transports and their two destroyer escorts made Palau safely on 18 March. And though USS TRIGGER (SS-237) reported attacking just such a convoy on the 15th (when she thought she heard the attack that led to TRITON's demise in the distance), neither AKIGUMO nor SAMIDARE noted any submarine contacts on the return voyage.

So who sank the TRITON? Might there have been another convoy in the immediate area that attracted and/or divided both submarines' attentions? And what of other Japanese destroyers operating in the region? And finally, as TRITON's exact area of operations at the time has not been revealed -- if known at all -- how great a "region" need be considered?

What follows might fairly be called "A Day in the Life of Japan's South Pacific Destroyers." So as to leave no stone unturned, the operating area reviewed is centered on Truk, and extends as far south as the Solomons, as far north and east as the Marshalls, and west to Palau and Saipan. Therein, on 15 March 1943, operated thirty- five destroyers flying the Rising Sun of Japan. We shall now examine their movements in detail.

After the Desdiv 10 escort group described above, the next best candidate for TRITON's conqueror is old AKIKAZE, which on 14 March was proceeding independently on Eleventh Air Fleet business from Kavieng to Kairiru Island, just off Wewak, New Guinea. At position 1-27 S, 147-21 E, north of Manus Island (in the Admiralties), she dropped depth charges on a submarine with "results unknown." AKIKAZE then continued on to Kairiru, where she arrived without further incident the following morning. As with SAMIDARE and SATSUKI, certainly a possibility here, but hardly the devastating attack so regularly attributed.

Rabaul was always a hotbed of Japanese destroyer activity, and mid-March 1943 was no exception. Even as Captain Yoshimura arrived there with KAZAGUMO, YUGUMO and SATSUKI on the 14th, another three came in from the Shortlands: ASAGUMO, YUKIKAZE and NAGATSUKI had just completed a transport run to Kolombangara in the Solomons. And FUMIZUKI and MINAZUKI spent the day on a similar mission to Surumi (near Gasmata) on the south coast of New Britain, returning to Rabaul on the 15th. None of the above-named ships recorded any antisubmarine actions in the course of their operations.

Two storied Guadalcanal veterans, URANAMI and SHIKINAMI of Desdiv 19, closed out their lengthy Solomons deployment just prior to TRITON's loss. The two cleared Rabaul together on 10 March but later parted company, URANAMI steaming to Palau and SHIKINAMI to Saipan. Both reached their respective destinations on the 13th without encountering any submarines en route.

Moving north to Truk we find thirteen destroyers in or near that great anchorage on 15 March, but none can be linked to TRITON. Six of these -- HARUSAME, HATSUKAZE, ISOKAZE, KAWAKAZE, MAKINAMI and UZUKI -- were out of service while repairing battle damage and thus a threat to no one. Available for miscellaneous local duties were ARIAKE, YUGURE, TANIKAZE, URAKAZE, UMIKAZE, AMATSUKAZE and OITE. The latter steamed a short ways out that day to meet the incoming tanker TONAN MARU No.3, but the rest appear to have remained within the atoll's confines. No actions against enemy submarines were recorded.

The only other destroyers which might have been considered near Truk that day were TACHIKAZE and AMAGIRI, inbound from Saipan and Japan, respectively, and HATSUYUKI going the other way. TACHIKAZE paused only briefly in Truk on the 16th before continuing south to Rabaul, and on the 17th attacked a surfaced, crash-diving submarine -- but again only with "results unknown."

Finally, Desdiv 31's ONAMI and KIYONAMI had sortied from Truk on 12 March with two troop transports, bound for Tarawa in the Gilbert Islands, and reached their destination five days later unmolested. And ASANAGI, at Jaluit in the Marshalls, was also in- between uneventful runs to Tarawa.

Having now exhausted all of the fairly well-documented candidates, let us return to Rabaul, where we must give careful consideration to a final three: MOCHIZUKI, YUZUKI and YUGIRI. Like several of those already covered, these ships' TROMs went missing after the war; unlike the others, their movements cannot be precisely extrapolated from those of their consorts. All are known to have been operating in the Southeast Area at this time, but without further specifics. Nonetheless, they intrigue. To wit:

MOCHIZUKI departed Sasebo on 1 March following repairs and is listed as having been on station in the Rabaul-area by the 10th. YUGIRI, also freshly-repaired, was in the same region from the beginning of February. The two would regularly operate together during April and May in the Solomons; it is thus not inconceivable that they could have joined forces against TRITON in March.

YUZUKI offers further food for thought, for it is now known that she in fact had at least one run-in with TRITON earlier that month (BKS v. 62, p. 299). Having sailed from Yokosuka on 18 February to "continue South Pacific escort duty," YUZUKI was the single escort to a group of five merchantmen attacked by TRITON between Truk and Rabaul on 6 March. In a series of day- and night-attacks on the convoy, TRITON succeeded in sinking KIRIHA MARU and damaging MITO MARU -- her last victims -- but was otherwise repeatedly turned away by the aggressive lone escorting destroyer, YUZUKI. One is tempted to speculate the outcome should the same well-handled destroyer have encountered the same submarine showing the same tactical "signature" just a week or so later.....

So, who sank the TRITON? The heavy weight of evidence -- that very conclusive if elusive attack report by the three mystery destroyers -- notwithstanding, this researcher is not alone in remaining skeptical of its veracity. Clay Blair, Jr., writes that, "After the war, U.S. naval authorities made an intensive hunt in Japanese records to determine the causes for each [AMBERJACK, GRAMPUS, and TRITON] loss. There were clues, giving rise to various speculations, but nothing positive was ever learned about any of them."

And Vernon J. Miller, in his meticulous and magnificient analysis of U.S. submarine sinkings, is himself forced to conclude that "Several loss possibilities exist, none with sufficient evidence to permit any definite conclusions." Miller seems to lean toward SATSUKI -- possibly as a result of correspondence with this writer -- but also notes a depth charge attack "presumably on the same day" by Japanese Subchaser No. 24.

It is of course recognized that a wide variety of small warships were frequently misidentified as destroyers, and that this might have been the case with TRITON's foes. (As it was with the ship that sank S-44 later that year: almost universally described as a destroyer, but in fact the 860-ton frigate, or kaibokan, ISHIGAKI.) The author has thus attempted to track the actions of these smaller craft as well, but cannot claim the same expertise, thoroughness, or perseverance with which the destroyers have been followed.

Who sank the TRITON?

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