Assassin’s mace (English adaptation of the Chinese phrase ‘shashou jiang’) — one periodically hears of the term used, usually in combination with advocacy for avoiding the same through transformational (forces)(TTP)(platforms)(weapons)(networks) – pick any, none, or all. Most recently, the ASBM the Chinese are purported to be developing has served as the poster child for Assassin’s Mace, but ’twasn’t always so. In the opening stages of the Pacific War, especially the period 1942-44, US forces were on the receiving end of a true assassin’s mace – the Long Lance torpedo. How was that? Well, let guest author, Chuck Hill (who will be bringing us the writeup on the 13/14 Nov 42 Guadalcanal action in the near future) explain… – SJS
P.S. Of course we are well aware of the irony in using a Chinese phrase to describe a Japanese weapon.

Type93torpedoProblems with American torpedoes are well documented. As a result of false economies and the arrogance of personnel charged with designing them, America’s new standard torpedoes, the Mk 13 air launch (also used by PT boats), the submarine launched Mk 14, and surface launched Mk 15, were never realistically tested before the war. They had problems which included the magnetic exploder, the contact exploder, and the depth keeping mechanism. But even if they had worked perfectly, American torpedoes were significantly inferior to Japanese surface and submarine launched torpedoes, as were every other torpedo in the world.

The giant 24 inch Type 93 “Long Lance” torpedoes in particular, were a secret weapon, expected to level the field with the numerically superior American Navy. Japanese pre-war planning had included special formations, the Night Battle Force (Yasen long-lanceButai) or Advanced Force, designed to exploit these torpedoes using night attacks. It was primarily the ships of the Advanced Force that would fight the night battles of the Solomons Campaign.

Like most of the torpedoes of the period, the most common Japanese surface vessel and submarine torpedoes were steam driven. In the case of the Japanese torpedoes, they burned Kerosene. Unlike virtually every other torpedo, they used pure oxygen rather than natural air to support combustion. Pure oxygen eliminated 77% of the gases of natural air that took up a great part of the volume of the torpedo, contributed nothing to the combustion process, but added considerably to the wake of the torpedo. This gave the torpedoes longer range at higher speeds with very little wake. Here is a statistical comparison of the respective surface launched torpedoes (from Campbell):

US Japanese
Mk 15 Type 93, Model 1, Mod 1,2
Diameter 21” 24”
Length oa 24’0” 29’6.3”
Total Weight 3841 lbs 5952 lbs
Charge 825 lbs 1080 lbs
Range 6,000yds/45 kts 21,900 yds/48-50 kts
10,000 yds/33.5 kts 35,000 yds/40-42 kts
15,000/26.5 kts 43,700 yds/36/38 kts

Not only were the torpedoes unique in their range and lethality. The supporting systems that employed the torpedoes were also unique. Oxygen generating systems were provided for topping up the pressure inside the torpedoes. Generally there was a reload torpedo for each tube and a system that allowed it to be reloaded in about 20 minutes. A notable exception was the torpedo cruiser conversions, Kitakami and Oi, equipped with no less than 40 torpedo tubes. Cruisers typically carried 16 to 24 torpedoes and destroyers 16 to 18.

To take advantage of the increased range, in some installations, the Japanese used a firecontrol computer comparable to that used for controlling guns in an anti-surface mode, worked by five crewmembers, that was good to ranges of 40,000 meters. They also took extra care to insure that their torpedoes ran straight and true.

While the Zero fighter came as a nasty shock; it should not have been, because it had been employed before Pearl Harbor, and an American Naval Attache had sat in one at an air show outside Tokyo in 1940. At least its qualities were quickly recognized and tactics were changed in an attempt to neutralize its advantages relatively quickly. In the case of the Japanese torpedoes, American commanders made tactical errors throughout virtually the entire Solomons Campaign because the range of these torpedoes went unrecognized. It did not have to have been that way, “in a rare occurrence, a volunteer agent brought the American Naval Attache in Tokyo detailed information about the Type 93 Torpedo. … But in 1940, when the American Office of Naval Intelligence (ONI) offered this information to its customers, insisting that it came from an ‘impeccable’ source, the Navy’s Bureau of Ordinance declared such a weapon to be impossible. Neither the British nor the Americans had yet mastered oxygen technology, so it was inconceivable that the Japanese had done so.” (Aldrich, p 64) Later, a type 93 torpedo was recovered, but no one seemed in any hurry to let the people who were actually fighting the war know about its exceptional performance. (Crenshaw)

(crossposted at

Aldrich, Richard James, Intelligence and the War Against Japan, Cambridge Press, 2000
Campbell, John, Naval Weapons of World War Two, Conway Maritime Press Ltd, 1985
Chesneau, Roger, ed., Conway’s All the World’s Fighting Ships, 1922-1946, Conway Maritime Press Ltd, 1980
Crenshaw, Russell Sydnor, Jr., South Pacific Destroyer, Naval Institute Press, 1998
Dull, Paul S., A Battle History of the Imperial Japanese Navy (1941-1945), Naval Institute Press, 1978
Lacroix, Eric and Linton, Wells II, Japanese Cruisers of the Pacific War, Naval Institute Press, 1997

USS Minneapolis (CA-36) after bow loss due to torpedo strike

USS Minneapolis (CA-36) after bow loss due to torpedo strike

Posted by SteelJaw in Navy

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    American Lessons Learned—the Hard Way

    Prior to the Solomons Campaign the Navy had almost no experience in surface war night engagements, and the Java Sea and Sunda Strait battles were American disasters. In contrast, the IJN had been practicing night maneuvers for years.

    1.) Chuck Hill has done an excellent job describing the Type 93, so there’s nothing to add on that score.
    2.) The new MK 14 American submarine torpedo was a disaster until its several faults were corrected in mid-1943. As a consequence, the contribution of American submarines in the Solomons was minimal. Only the MK 10, found only in the obsolescent S-Boats, was reliable—as exemplified by S-44’s sinking of Kako, homeward bound for Kavieng, the day after Mikawa’s stunning victory at Savo Island. With this in mind, one can only wonder why COMSUBPAC (RADM English) failed to order several S-Boats to the Slot north of Savo to intercept the inevitable “Tokyo Express” runs. One should also remember that Japanese ASW resources were slim at this time in the war.
    3.) The Japanese had no radar at the time, but their extensive night training and superior optics more than compensated for this.
    4.) The Japanese had superior pyrotechnics and knew how to use them—especially with their cruiser floatplanes at night.
    5.) Until the success of Arleigh Burke’s DesRon 23 (fall 1943), the Americans appeared to have little or no effective night engagement doctrine. Compare this with Mikawa at Savo, who took seven cruisers into battle which had never worked together before, and basically left running the fight up to his individual captains.

  • Byron

    In the early years of the war, most Admirals saw Submarines not as offensive weapsons, but as scouts.

  • Chuck Hill

    I can’t help but speculate that the captured torpedo was sent to the torpedo station for analysis and when they saw how much more advanced it was, they were embarrassed to publish the findings.

  • UltimaRatioReg


    Great job describing a game-changing weapon. Was it Morrison who nicknamed the Type 93 the “Long Lance”? And great comments from CINCLAX. Clearly, the IJN had thought through the night surface combat problem and designed supporting technology, training, and tactics accordingly. The USN, on the other hand, feared the night and their enemy in the dark. A good lesson for folks today who want to voluntarily surrender parts of the warfighting spectrum to our enemies….



    You’re absolutely correct about the arrogance and parsimony of BuOrd.

    Read a biography of RADM Ralph Waldo Christie and you’ll find the biggest source of problems with the American MK 14 torpedo.

  • Chuck Hill

    It’s really fortunate the Japanese did not realize how bad our torpedoes were. As Crenshaw pointed out in Sout Pacific Destroyer we had some success with torpedoes at Balikpapan and with PTs in the Philippines but those were with older mark torpedoes, the Mk 8s, but no one seemed to notice.

  • Grandpa Bluewater


    The other part of the MK14 story is that the problem was solved when the TYCOM listened to his subordinate boat CO’s, ran an honest test, and told his subordinate support activity (Torpedo Shop, SUB BASE PEARL) to find out what was wrong and FIX IT.

    Which they did, promptly.

    All it took was a p.o.’ed CO with the guts and guile to get the Force Commander’s attention, and a RADM cut from the same cloth to listen, get it checked out, and get it fixed at the waterfront level (which the “experts” always say can’t be done).

    Of course, it had to wait until the plane with RADM Lockwood’s predecessor on it crashed and killed all on board, so “Uncle Ernie” could become COMSUBPAC.

    Good submariners still remember.

    So why is it exactly that (lately) new submarines come in ahead of schedule and under budget (for the moment), and results vary elsewhere in the USN?

    Could it be…Leadership?…at all levels?

  • UltimaRatioReg

    “All it took was a p.o.’ed CO with the guts and guile to get the Force Commander’s attention, and a RADM cut from the same cloth to listen, get it checked out, and get it fixed at the waterfront level (which the “experts” always say can’t be done).”

    They did all that without Lean Six Sigma belts? Without sensitivity and diversity training? Wow. I bet some of them even smoked.

    The story of whom the BIG Navy blamed and ridiculed instead of identifying the problem is as maddening as the story of the solution is inspiring.


    Grandpa Bluewater…

    The way I heard it was that a couple of chiefs at Sub Base Pearl sorted out the MK 14 contact exploder problems by lightening up the mechanism with parts machined from the propellers of downed Japanese planes on Dec. 7th.

    Do you or anybody else out there know if this story is, in fact, true?

  • Bill Bullard

    Actually, one of the best submariners, divers and engineers the Navy ever had fixed it.

    CAPT Charles Momsen (of SQUALUS rescue fame) investigated the Mk 14 exploder issue and developed the new exploder when he was SUBRON 2 in 1943.

  • Grandpa Bluewater


    Chiefs are always part of the solution, that’s what they are for
    (Young’ns, you have to explain the most basic stuff).

    It was the whole shop and some helpers. Among whom were Swede Momsen, one of the brains of the operation. (Captain Momsen was inventor of the Momsen Lung, coinventor of the McCann rescue chamber, basically came up with the ASR’s design, which adapted to a flyaway kit is still in use) and lead salvor on the Squalus. These names keep turning up.)

    The machine shop guys machined new firing pins from scrapped aircraft propellors because the old ones had too much inertia to work properly (did the TMC talk to the MRC? I’d say yes. I’d say Momsen understood command by negation, too.)

    That was after they fixed the problem of the torpedo running deeper than set.

    Then they eliminated the magnetic exploder. The magnetic exploder could detonate prematurely depending on the dip and intensity of the magnetic field of the earth at any given location. Not suprisingly, the South and Central Pacific were a little different than Newport, RI. So they disconnected that; new ones later were manufactured with a weight that fit in the hole the sensing coil went in so weight and balance were right.

    That fixed, they tackled the problem that the firing pin would malfunction except for glancing impacts (the inertial thing).

    They fixed it damn quick too.

    Nobody worried too much about credit, had a war to win.

  • Ok, I have to ask: when did the capabilities of the Long Lance get recognized in general by the West? Was anyone ever told during wartime? Were operational commanders ever aware of the range and capabilities of this weapon, or did it take the end of WW 2 and some historians to find all this out?