
Chapter 2. Deaths at sea
Over 250,000 deaths at sea
Among the narrow definitions of casualties that occur during conflict, a number of particular manners of death stood out during the war. One of these was the large number of deaths that occurred at sea.
Attacks by aircraft belonging to allied fleets and submarines during the Asia-Pacific War resulted in a considerable number of ships being sunk, although it should be noted that deaths at sea here refers to those who died when their ships were sunk. Detailed estimates on the number of deaths that occurred in this manner are included in my previous work “The ecology of the former Japanese Imperial Army and Navy”, so here I will only use round numbers. (42)
According to the “Compendium of research on fatalities resulting from the sinking of vessels during the Pacific War”, the number of deaths at sea came to 182,000 in the case of the navy and navy-affiliated personnel, while the army and army-affiliated personnel deaths came to 176,000, making an overall total death toll of 358,000. By way of contrast, the total number of casualties for both the Japanese navy and army during the entire Russo-Japanese War was 88,133 (source: A military historical study of the Russo-Japanese War). This reveals the scale of the loss of so many personnel. Furthermore, the Army Medical Service for Transport Vessels, in its own report, pointed out that “Almost half of all deaths that occurred during combat aboard transport vessels should be ascribed to drowning” (source: Transport Ship Hygiene). (43)
The leading cause for so many deaths at sea was the great success that US Navy submarines had in sinking ships. During the course of the Second World War, the US Navy lost 52 submarines, yet it managed to sink 1,314 vessels, making a combined commercial tonnage of 5.2 million tons. What this meant is that for every US submarine sunk, it managed to sink 25 commercial Japanese ships. The German Kriegsmarine lost 781 U-boats during the war but sank 2,828 commercial vessels, for a combined tonnage of 15.5 million tons. This resulted in a U-boat loss to vessel sunk ratio of 1:3.6, thereby giving the US a comfortable lead. However in the case of the Japanese Imperial Navy, it lost 127 I-class submarines but only sank 184 commercial ships, for a combined tonnage of 500,000 tons. This resulted in a loss to sunk ratio of little more than 1:1.4. (43)
The US Navy’s submarine campaign against Japan underwent a dramatic shift from around the middle of 1943. The US Navy not only managed to reduce the number of defects in its torpedos, which up until this time had suffered from either premature detonation or failure to explode, it also successfully broke Japan’s commercial shipping codes. This made it possible for US submarines to lie in wait for transport ships and ambush them (source: Research notes concerning the campaign to destroy Japan’s commercial shipping). (43)
Another reason for why so many Japanese troops died at sea was because most of the commercial vessels used to transport troops by the Imperial Japanese Army were requisitioned cargo ships. The interior compartments of these ships were narrow and cramped, despite being renovated, and hosted large numbers of troops. As a result, when these ships began to sink, it became impossible for all of the personnel on board to escape. In time, the loss of so many commercial vessels led to a shortage in ships, which meant that many of those ships still available were then overloaded with men and materials. This then exacerbated the amount of losses in personnel suffered when these ships were sunk. (source: Battlefields and Soldiers of the Asia-Pacific War). (44)
The Transport Ship Hygiene of the Army Medical Service for Transport Vessels, quoted earlier, pointed out that one of the particular characteristics of transport ships was the narrowness of the living spaces. Military transport ships had, on average, between 3 to 4 soldiers occupying a space of 1 tsubo (around 3.3 metres squared). If 5 fully laden soldiers occupied a space of 1 tsubo, it would have been impossible for any of them to freely move about. In September 1944, Fukuoka Yoshio, a trainee medic on board a transport ship heading for The Philippines, wrote the following about his experience on the ship (44):
“Like slaves on board a slave ship, soldiers were crammed into the hold of transport ships over and above the prescribed number of crew. Those who couldn’t get up on deck suffered from a debilitating fever (heatstroke) because of the dramatic increase in temperature and humidity in the hold. This led an increase in body temperature and the onset of shock. Over time, soldiers lost complete control over regulation of their central nervous system and many died. Whenever this happened, I would accompany the body for burial at sea. I witnessed many a sad, tragic end, as the body of the soldier, with no relatives to farewell it, disappeared beneath the waves.” (source: A Doctor’s Greater East Asian War) (44)
According to Dr. Fukuoka, one reason that many of the younger soldiers who had just joined the army couldn’t go up on deck was because many of the veterans had parked themselves and their equipment near the exits to the deck in order to make use of the fresh air for themselves. (44)
“The 8-knot convoy” – Applying the spurs to a worn-out fleet of cargo ships
Another problem that the military faced was the lack of capability in Japan’s transport fleet. During the Pacific War, in order to meet the military’s demand for transport vessels, a large number of ships were constructed that met wartime specifications. Simplicity in design and construction, a shortened construction schedule, and savings on material and labour meant that speed of construction was prioritized to the detriment of the vessel’s capability. (45)
A variety of wartime-regulation ship types were constructed during the war. If we examine the speed at which such cargo ships travelled, a 1st generation cargo ship had a top speed, in the fastest class, of 12.3 knots, while the slowest type had a top speed of 10 knots. A 2nd generation vessel could move, at the fastest, at 10 knots, while the slowest moved at 7 knots. A 3rd generation vessel could move at 14 knots at the fastest, and 7.5 knots at the slowest. A 4th generation vessel, which prioritised speed, could move at a top speed of 18 knots (source: A History of Wartime Ship Construction). (45)
Transport ships and tankers would make up part of a naval convoy where they would grouped together to protect them from attacks from submarines and aircraft. Some ships within these convoys travelled at the comparatively low speed of 8 knots (around 15 kilometres an hour), which forced the remaining ships to modify their speed to match that of the slowest vessels. Such convoys were referred to as “8 knot convoys”. These became the norm in time, which caused considerable problems for those vessels ordered to escort them. (46)
To protect these “8 knot convoys” from submarine attack, the convoy would engage in zig-zag manoeuvres known as “noji manoeuvres” (because of the resemblance the movements had to the character no, or 之). This often resulted in convoys having to drop their speed to 6 knots in order to successfully complete such manoeuvres (source: A Record of conversations with the Commander of the Combined Fleet). (46)
Let’s have a look in more detail at what happened to transport ships after they had been attacked. Both fatalities and injuries would result from explosions caused by either torpedos or bombs. Within the ship this could provoke different reactions - from those who froze out of fear, to those who lost all sense of reason. Even though you might successfully escape from inside the ship, there would be a scramble to get hold of floating equipment like boats and rafts. According to the “Military Regulations - No.49 - Lessons for use during difficulties at sea” (dated 18th January 1945)
“Either seize a flotation device or get hold of one and use it exclusively. Do not worry about others but save your own life. There are many examples of sailors losing their lives trying to save both themselves and others.” (46)
One example of this ‘survival at all costs’ mentality was the tragedy that struck the ‘Taiseimaru’. In April 1945, the Taiseimaru (1,948 tons) was making its way to Hakodate as part of the 3rd Amphibious Brigade. After being attacked by a submarine, she sank in the seas off Niikappu Seppuchõ in Hokkaido. (source: A History of Wartime Shipping). One crew member of the Amphibious Brigade, Õyashiki Kiyoshi, provided an eyewitness account of what happened next:
“Soldiers floating around in the sea called out for help from the “Taihatsu” (an amphibious boat) and attempted to cling onto its side. I then saw an officer draw his sword and cut the arms off a number of soldiers (armless corpses later washed up on nearby beaches).” (source: Survey materials concerning records of wartime experiences and conversations, Vol.1). (47)
The writer Yoshimura Akira would cover this incident and use it for the basis for his story “The Sea Casket”. However he would supress the name of the ship, the unit involved, and the name of the place where the incident occurred. (47)
Pressure injuries and injuries from underwater explosions
Other forms of injury that occurred when a vessel sunk, but which were not widely recognised as war injuries, were pressure injuries and injuries that resulted from underwater explosions. Pressure injuries usually refers to injuries that occur from the shock that the body (such as the legs) has to absorb after landing on the ground or a hard surface following a fall from a great height. However Lieutenant Yamada Junichi, of the former Imperial Army Medical Corps, had a particular fascination with the problem of pressure injuries caused as a result of military action, and made the following observation about this phenomenon:
“During the recent war, ship explosions resulting from hits from individual mines (underwater mines or torpedos) created the opposite effect to what would ordinarily happen. An explosion would create such a shockwave that personnel on either the deck of a ship or in the water would be sent flying through the air. In addition to severe pressure injuries, there were other forms of injury including wounds from the explosion itself, contusions, bruising, fractures, burns, perforated eardrums, and internal injuries which ranged from simple to severe. It was common for multiple injuries to temporarily combine to form one major injury.” (source: War diary of a medical officer sent to The Philippines) (47, 48)
According to Yamada, among the recorded fatalities that occurred after being sunk, “44% had pressure injuries that accompanied (their other injuries).” (48)
But what about injuries that resulted from underwater explosions? Another medical officer who served during the Asia-Pacific War, Kunimi Hisahiko, knew of the type of wounds that could result from underwater explosions as a result of his studies at the naval medical school. In his memoirs, he wrote:
“If an explosion happened to occur near someone floating in the sea, the organs of the victim would begin to rupture one after another despite the absence of any visible wounds to the outside of the body. They would suffer severe abdominal pain, which would gradually lead to emaciation and then death. It was a horrible way to die. At first, we didn’t know what the cause of death was, but soon learnt that it accompanied anyone who had been in the vicinity of an underwater explosion caused by a depth charge.” (source: Diary “Onkõ Chishin”) (48)
Depth charges were the most common form of anti-submarine weapon. They were carried by destroyers and submarine chasers for use against enemy submarines in order to protect convoys. They would either be dropped or launched from an anti-submarine vessel and would explode underwater. (48)
One record of the type of casualties that resulted from underwater explosions was documented by naval medical officer Hatano Katsumi. In January 1944, Hatano was stationed at Rabaul where he was responsible for providing medical assistance. In his memoir of the war, he wrote:
“I had never treated so many suffering patients before. Patients would complain about the terrible pains in their stomachs, which were so painful that it would make them cry. They would be vomiting up blood.” (source: The Cave Hospital of Rabaul)
Hatano would later recognize what the cause of these injuries was. In June 1942, Lieutenant Satõ Mamoru graduated from the naval medical school. In July 1944, Satõ found himself on Cerebus Island and responsible for operating on patients suffering from injuries caused by underwater explosions. In his memoirs, he wrote:
“The crew of a cargo ship that had been torpedoed and sunk by an enemy submarine found themselves floating in the sea. The shockwaves caused by depth charges dropped by friendly submarine chasers carrying out attacks on enemy submarines would cause ruptures in the intestines of these sailors. Soon there were around ten patients who had contracted peritonitis all at once. (Abridged) When we opened their intestines up, we were astonished to find that the intestines of all of the patients had suffered ruptures in various places. There was a peculiar trait to that part of the body, (Abridged) and so from that we were able to discern that the injuries were not a result of the shockwave passing through the wall of the intestine, but rather explosive pressure had forced its way into the intestine via the anus, and damage to the intestine wall had thus occurred from within the intestine itself.” (source: Clouds over the sea) (49)
Hence although we might think of only one type of death at sea, in truth death came in many different forms. (49)
“There were a sudden series of incidents of men going mad”
One further issue regarding deaths at sea that can’t be ignored was the psychological trauma that accompanied any experience of being sunk. As losses in shipping began to dramatically escalate, a sense of dread would spread among the troops onboard a transport ship making its way out of port. From February to March 1943, a campaign was waged to increase the amount of supplies reaching New Guinea. During the ‘81st campaign’, aerial attacks by US and Australian aircraft resulted in the loss of 8 cargo transport ships and 4 destroyers, thereby annihilating an entire convoy. This was referred to as the ‘Battle of the Bismarck Sea’ (in English, or the ‘Dampier Strait Tragedy’ in Japanese). (50)
Tsuchii Zenjirõ wrote the following words in his memoir, based on his notes taken in relation to the state of the soldiers and crew scheduled for embarkation:
“Many of those marked for embarkation would gradually fall ‘silent’ and begin to feel ill. In the afternoon of the day before embarkation, when tension had reached its maximum point, there were a sudden series of incidents of men going mad among the soldiers making their way into the holds of the transport ships. This became a serious problem. What is more, these men were so affected (by their madness) that they clearly weren’t faking it.” (source: Records of crews from sunken vessels) (50)
The state of mind of troops who had been rescued after their ships were sunk was also a serious issue. In a number of military reports, personnel who had been rescued after “being in a perilous situation”:
“would ordinarily display a more sensitive mental state for some time afterwards, particularly a heightened sense of fear” which, it was noted, would interfere in the performance of the soldier’s military duties (source: “Lessons for use during difficulties at sea” quoted earlier) (51)
There were also regiments who, along with losses in men and materials, also lost their battle flags. Battle flags were flags presented to small infantry and cavalry units by the Emperor at the time of their formation. Along with the psychological, almost mythical, importance attached to objects received directly from the Emperor, it symbolised the unity, or the cohesiveness of the particular regiment. These were the flags that sank together with their regiments. (51)
A specific example of this occurred in November 1942, when a ship carrying the 170th Infantry Regiment was torpedoed by a submarine in the seas off Palau, resulting in the loss of the regiment’s battle flag. In April 1944, the 210th Infantry Regiment suffered the loss of its battle flag when their transport ship was sunk in the Bashi Channel. And again, in August 1944, the 13th Infantry Division suffered the loss of its battle flags when their transport ships were also sunk in the Bashi Channel by submarine-launched torpedoes. (source: Infantry and Cavalry Units and their Battle Flags). (51)
One could say that this was a fitting symbol for the destruction of “the Emperor’s Army”. (51)