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Role of Merchant Marine for the Allies

Info: 5449 words (22 pages) Essay
Published: 8th Sep 2017 in Military

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“The men and ships of the Merchant Marine have participated in every landing operation by the United States Marine Corps from Guadalcanal to Iwo Jima — and we know they will be at hand with supplies and equipment when American amphibious forces hit the beaches of Japan itself.”

Lt Gen Alexander A Vandergrift, Commandant US Marine Corps[1]

Merchant Marine in the Second World War. The role of merchant marine in World War II (WW II) has been adequately expounded by many scholars. The merchant marine ships as carriers of essential materials both for civilian sustenance as well as for continuance of war effort for both the Allies as well as Axis powers became the raison d’ etre of some of the most pitched battles during WW II. Control of trans-Atlantic lines of communication for the Allies and their interdiction by the Axis powers led to the Battle of the Atlantic which lasted the entire duration of WW2.[2] Highly publicized and extensively analysed, this battle remains the most epochal sea battle involving merchant marine. The Asia Pacific region on the other hand, witnessed trade warfare of almost equal intensity but on a much lesser scale. The effectiveness of measures employed by both Axis and Allied forces to interdict each other’s merchant marine in this region decided the outcome of the Pacific war to a large extent.

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Asia Pacific – Reversal of Strategies against Merchant Marine. What lends a modicum of uniqueness to the Asia Pacific region is that the policies adopted by Allies and the Axis powers against merchant shipping here were diametrically opposite to those being adopted by them in the Atlantic theatre at the same point in time. Japan in the Asia Pacific was faced with the same challenges as Great Britian in the Atlantic in terms of dependence on Sea Lines of Communication (SLOCS) for sustaining her war waging effort. Her merchant shipping was being targeted by the US submarine fleet much in the same manner that the German U boats were sinking Allied shipping in the Atlantic. Yet, Japan could not put into place effective convoy tactics similar to those that the Allies employed against the German U boat wolf packs. In addition, Japanese U boats remained largely ineffective in checking the Allied offensive owing to flawed doctrinal approach. Hence, understanding the reasons behind this reversal of strategies towards trade warfare is germane to understanding the overall contribution of merchant marine in the Asia Pacific.

Success of Allied Merchant Marine Support. While Japan was economically strangulated through interdiction of her merchant marine, the Allies innovated to keep their ships fighting fit despite an acute lack of bases to do it from. The implementation of Advanced and Floating Bases[3] in the Pacific theatre and the yeoman service provided by Service Squadrons Eight and Ten[4] during the operations in the Asia Pacific region are indeed benchmarks as far as synergising the efforts of merchant marine and the fighting forces is concerned. Effective support of merchant marine proved to be a force multiplier for the Allies and allowed them to successfully wage a war of attrition against Japan.


This paper seeks to study the role of merchant marine for the Allies and the Axis powers in the Asia Pacific region in WW II by examining the effects of trade warfare, Naval Control of Shipping (NCS), convoy ops and U boat doctrines on both the sides. The paper would make recommendations relevant to the Indian context with special emphasis on Naval Cooperation and Guidance for Shipping (NCAGS) measures.[5]


Requirement of Merchant Shipping – Asia Pacific Region

Axis Merchant Marine in Asia Pacific. The Axis merchant marine plying the Asia Pacific region belonged entirely to Japan. Prior to the outbreak of war, Japanese merchantmen were employed for transporting oil, iron ore, military hardware, etc. from USA, UK and her colonies and the Dutch East Indies.[6] After Japan attacked Indo China in May 1941, the USA responded with sanctions and cut off all trade. In order to keep the war machine moving, Japan now started importing oil from Indonesia, coal from Manchuria, rubber and iron ore from Malaya. With the outbreak of war, Japanese trade and her merchant marine were extensively plying within the Western Pacific region. One special aspects pertaining to the internal organization of merchant marine in Japan bears mention. Unlike the Allies, where merchant marine requisitioned for war effort was under a single point control, in Japan, merchant shipping was divided between Imperial Japanese Army, Imperial Japanese Navy and Ministry of Communication. The absence of a central coordinating agency left the merchant marine fractured in administration eventually leading to wastage of significant amount of tonnage.[7] The Japanese were singularly dependent on their merchant marine for sustaining the war on Allies. At the outbreak of war, Japanese merchant marine was about 6,000,000 tons which was considered just about adequate to meet their national needs.[8] The Japanese, having never been subjected to significant trade warfare did not have a well-defined structure of NCS.

Allied Merchant Marine in Asia Pacific. The Allies had a significant merchant marine presence within the Asia Pacific region. The US itself had more than 1700 merchantmen[9] assigned to the Pacific theatre of which 450 merchantmen eventually participated in Pacific theatre combat operations. These ships were awarded Battle stars for their distinguished service.[10] Allied merchant marine in the Asia Pacific while being predominantly of American origin also had generous contribution from Australia, New Zealand, UK, Netherlands and Norway.[11] Movement of merchant ships within the theatre was relatively unopposed as compared to the Atlantic theatre. This was made possible due to an almost negligible Japanese submarine threat. In addition, the Allied NCS procedure were tested and proven in combat thereby streamlining the entire process of merchant marine movements, defensive measures, intelligence gathering, etc.[12] But what posed a significant problem for the Allied war effort was twofold: –

  • Lack of Bases for Stockpiling and Repair Activities. The vast expanse of the Pacific Ocean provided very few shore bases to set up stockpiles/ forward bases. This aspect gains significance because the numbers involved in supporting the fighting forces were indeed astronomical. For eg on Efate, the U.S. had seven 1,000-barrel steel tanks for aviation gasoline, two 10,000-gallon Diesel tanks, and four buried 5,000-gallon aviation-gasoline tanks, while at Havannah eight other buried tanks held 5,000 gallons each. In the Tulagi area the U.S. had ten 1,000-barrel tanks plus 12,000 barrels of aviation gasoline, a 60-000-barrel diesel-oil storage, and a 280,000- barrel fuel-oil farm. Guadalcanal added storage for 1,300,000 gallons of aviation gasoline.[13] The condition described above was reached in the initial phases of the offensive.
  • Enhanced Distances of the Pacific.The Pacific Ocean stretches through 135° of latitude, 9,600 miles. Its greatest longitudinal extent measures 12,000 miles along latitude 5° N, covering an area of 63.8 million square miles.[14] An average voyage across this expanse of water from San Francisco to the closest island outpost in the Solomon Island chain would take in excess of 25 days provided the weather was favourable. Thus moving logistics across this vast expanse was a unique problem. Maintaining continuous flow of materiel in this theatre where an average soldier required 67 pounds of supplies per day was indeed a daunting challenge.

Allied Efforts to Surmount Logistical Challenges

Setting Up of Allied Mobile Service Squadrons. Based upon the above two peculiarities of the Pacific theatre, Admiral Nimitz ordered setting up of two mobile service squadrons. The basic idea was to use one mobile service squadron to support the fleet till achievement of one military objective. In the meantime, the second mobile service squadron would be set up ahead near the next objective. This way, the Fleet could continue its forward march and the support squadrons would leapfrog ahead.[15] This idea fit in well with the island hopping campaign. The service squadrons were an eclectic mix of naval ships, merchantmen, fleet auxiliaries and a number of specialized vessels. The combination of vessels, surface craft, and auxiliary equipment under the operational administration of the Service Squadron included: provisions stores ships, barracks ships, oil tankers, hospital ships, destroyer tenders, hydrographic survey ships, net cargo ships, net tenders, repair ships, pontoon assembly ships, submarine chasers, motor torpedo boats, picket boats, rearming boats, buoy boats, harbour tugs, salvage tugs, self-propelled lighters, ammunition barges, salvage barges, garbage barges, repair barges, floating dry-docks, degaussing vessels, floating cranes, salvage vessels, net gate barges, and any other type of ship considered necessary.[16]

Analysis.A comparative analysis of both the Allied and the Axis merchant marine indicates that at the beginning of the Pacific War, both the forces had relatively high freedom of manoeuver with merchantmen having a clearly understood charter. The Allies had an edge over the Axis merchantmen in that they were under a unified and unambiguous command structure. This edge also extended to the synergistic approach towards their utilization in conjunction with fighting forces. On the contrary, Japanese attitude towards managing affairs pertaining to joint ops with merchant shipping and convoy ops was one of derision. Managing trade and merchantmen did not figure in the classical Mahanian concept of seapower which the Japanese were assiduously emulating and hence gave it only a peripheral treatment.[17]


Effect of Trade Warfare

Allied U Boat Offensive.The Allied U boat offensive in the Pacific theatre commenced in Jan/Feb 1942. The Allied submarine fleet in the Pacific comprised of submarines from US Navy, the Royal Navy of UK and a few small submarines from the Royal Netherlands Navy. The US Navy adopted an unrestricted submarine warfare policy. In addition to the same, they also adapted Wolf Pack tactics practiced by Germans in the Atlantic to utilize them in the Pacific theatre.[18] The nomenclature selected for the Allied Wolf pack was Coordinated Attack Groups (CAG).[19] The tactics were slightly refined to give more freedom to the submarine commander at sea and control from submarine commander ashore was reduced. Other than minor changes, the spirit of CAG was similar to the Wolf pack. The CAG offensive against Japanese trade proved quite effective. The US submarines alone sank a total of 4,779,902 tons of merchant shipping during the course of the war, in total accounting for 54.6% of all Japanese vessel losses.[20] Allied trade warfare thus, succeeded in strangulating Japan and prevented her merchant marine form aiding the war effort.

Axis U Boat Ops against Allied Merchant Shipping.Japanese U boats were never tasked by the Japanese Naval High command for an all-out trade warfare role against the Allied merchant shipping. This was attributable to certain flawed doctrinal precepts which shall be discussed subsequently. In the Pacific war, the Japanese submarines have been credited with sinking of 184 merchant vessels amounting to a total of 907, 000 GRT.[21] This kind of a restricted offensive had no effect on the Allied merchant marine.

Effect of Convoy System in Asia Pacific

Japanese Convoy System. In view of the relentless U Boat onslaught on its shipping the Japanese response was decidedly inadequate. Regular convoy system was put into place only by 1943 by when Allied U boats had already sunk a tenth of the Japanese shipping. The escorts provided for convoys were inadequate numerically as well as in terms of capability. These escorts were ships which had lived their life in the Imperial Japanese Navy and were seconded for lesser important roles. This gross neglect continued till about Mar 1944 when merchant ship losses became prohibitive. The blockade of the Japanese mainland had started to pinch the war waging effort as almost half the Japanese merchant fleet had already been sunk. This is when, serious attention to Japanese convoying efforts was paid by Japanese High Command. The total number of escort units assigned for convoy ops went up from 25 in 1943 to 150 by 1944. Even then the numbers of escorts were inadequate and poor ASW technology did not prevent losses from U boats in a big way.[22] Poor ASW capability of IJN ships remained its proverbial Achilles’ heel. This deficiency led to further attrition of not only its merchant shipping but a substantial amount of its combatant fleet as well.[23] By the time Japanese Navy put into place a shipbuilding system for manufacturing specialized ASW platforms they ran out of raw material. And so by 1945, their war machinery as also the economy came to a standstill.

Effect on Japanese Convoy Routes.The cumulative effect of Allied U boat offensive and inability of Japanese Navy to offer effective protection to its merchant marine convoys led to abandonment of a large number of point to point routes within the Western Pacific ocean. By 1944, more and more convoys were hugging the coast during their transit making them more vulnerable to threat from mines as well. This led to transit time being doubled in many cases over well-established routes. An extract from Strategic Bombing Survey – The War Against Japanese Surface Transportation (1947) is placed at Appendix which depicts the Japanese convoy routes that were abandoned during the course of the Pacific war due to the U boat offensive from Allies.[24]

Japanese Submarine Doctrine. Having seen the proactive Allied U boat deployment policy which proved to be so effective against Japanese shipping, it is worthwhile to examine the Japanese U boat doctrine within the same period of time as well. The strong Mahanian outlook of the entire Japanese Naval leadership, who had been bred on tales of crushing defeat meted out to Russia in the Russo Japanese War, led them to adapt a submarine doctrine edificed on the following assumptions[25]: –

Submarines are suited for use as scouts and must engage enemy surface combatants. They must support the Grand Fleet in the decisive battle.

Sinking merchant ships is not consistent with “bushido” (the way of the warrior) as the enemy can be destroyed by crushing his large combatants.[26]

Submarines could be used as effective means for defending island garrisons.

Analysis.In a broad stroke, it could be surmised that since the basic premises on which submarine doctrine of the Japanese were based were not sound, the overall exploitation of these assets became unfocussed and suboptimal.[27] The Japanese were forced to cede that their U boats soon became powerless when faced with the superior ASW and technological capabilities of Allied warships. U boats could not defend island outposts of Japan and soon became supply mules for them which was a complete waste of their combat potential. Despite these telling setbacks, the Japanese high command was steadfast in refusing to recognize the effectiveness with which the Germans and later on the Allies exploited U boats. And so was frittered away a potent force which could have altered the face of Pacific war had they been used in an all-out merchant offensive against the Allies near the US West Coast, Hawaii, Australia, New Zealand, the Panama Canal and closer to major Indian ports/choke points.


Factors which Decided the Role of Merchant Marine in the Asia Pacific Region. During the course of the analysis of the role played by merchant marine in the Asia Pacific region in support of the war waging effort of both Allies and the Axis powers during WW II, the following major factors could be surmised: –

Trade Warfare.It is beyond doubt that the war in the Asia Pacific was one of logistics in its simplest form. The Allied forces built up a phenomenal logistics chain through synergised use of merchant marine in conjunction with fighting forces. The aim of the Allies was to effectively use this logistics stockpile to support their forces so as to cut the logistics lines of Axis powers. In cutting the Axis SLOCS, the aim was again to interdict Axis merchant marine which was the veritable lifeline of Japan. Hence both sides were inexorably dependent on their merchant marine for sustaining their war waging efforts. The role of merchant marine for both the side was pivotal. In this scenario, successful application of trade warfare allowed Allies to strangulate Japan and achieve significant advantage.

Naval Control of Shipping. The major difference which contributed in a large way towards the overall effectiveness of Allied merchant shipping was the astute single point command and control. The Allies were fully aware of the importance of merchant shipping and had learnt their lessons well from the Atlantic theatre. On the contrary, Japanese shipping was divided between the Imperial Army, Imperial Navy and the govt with no central agency overseeing their functioning and utilization. This led to avoidable wastage of precious mercantile effort. Poor administration on part of the Japanese also led to non-implementation of convoy system in the early stages of war. Lack of effective NCS resulted in significant destruction of merchant marine which led to their economic strangulation and paved the way for their ultimate defeat at the hands of the Allies.

Convoy System.The Allies did not have the need to implement a strict convoy system in the Asia Pacific unlike in the Atlantic theatre. This was due to an almost complete absence of Japanese submarine threat. The Axis shipping while in desperate need of effective convoy ops in the face of overwhelming U boat threat never got its act together while there was still time. By the time convoy ops were implemented by the Japanese, Allied U boats had inflicted irreversible losses on Axis shipping. The numerical and technical deficiencies of the Axis escort forces which were finally assigned for convoy ops only facilitated the attrition of Axis shipping which contributed in a big way to the ultimate Japanese defeat. Hence, ineffective implementation of convoy system by the Japanese prevented their merchant marine from playing a key enabler’s role to the war effort at the most crucial time during the Pacific war.

U Boat Doctrines. The Allies took a leaf out the Axis powers’ Wolf pack tactics and implemented the same with great success against Japanese shipping. This was made possible due to a realistic approach by the Allied Naval leadership. The Axis powers on the other hand showed a complete lack of imagination in exploiting the U boat forces that they had. Rather than target Allied merchant shipping in a tit-for-tat manner, the Japanese U boats were frittered away on supply missions to outlying garrison islands and audacious reconnaissance missions which ultimately did nothing to further Japanese objectives. The Allies in fact won the war on Japanese merchant shipping by astute application of their potent U boat fleet with an aggressive doctrine.


NCAGS for Protection of Merchant Marine in Conflict and Peace

Amongst all the factors that have been enumerated above, one factor that stands out as a significant contributor to the destruction of Japanese merchant marine was their lack of well evolved NCS procedures. The effectiveness of NCS has been proved both in war and in peacetime operations over the last century. The most recent example of successful application of these time tested procedures can be seen in the escort operations being conducted by IN, PLA(N) and Russian Navy in the Gulf of Aden for protecting ships from the scourge of Piracy.

NCS and NCAGS in the Indian Context. Specifically, in the Indian context, NCS and NCAGS are both mentioned as distinct military roles in times of conflict in the maritime strategy document, Ensuring Secure Seas – Indian Maritime Security Strategy. However, no further amplification on the ambit of operations is provided therein.[28] The Australian Maritime Doctrine (non NATO member) defines NCAGS as “The provision of military cooperation, guidance, advice, assistance and supervision to merchant shipping to enhance the safety of participating merchant ships and to support military operations. (BR 1806)”.[29] Certain amplification of the scope of NCAGS is also provided in the doctrine to the extent that the overall aim of the operation becomes clear.[30]

Need for Guidance Document on NCAGS.Presently there do not exist any Indian guidance/ policy documents in the open domain with regards to NCS/ NCAGS which are accessible to merchant mariners. It is recommended that the ambit of operations envisaged under NCAGS could be defined in an unclassified guidance document. In specifying a scope for these operations we could consider the NATO Allied publication in this regard which has evolved from the Wartime Instructions for US Merchant vessels of WW II.[31] This NATO publication incorporates actions for a number of non-traditional threats which plague merchant marine in the present day. Promulgation of such a document would lay out the basic guidelines for co-operation with merchant men. This document could be used to lay out the terms of reference for carrying out Anti-piracy escort ops in Gulf of Aden. Once a policy/ guidance document is promulgated, a foundation for mercantile-military cooperation is laid for building up further.

Participation/ Observer Status in NATO NCAGS Exercises.NATO member navies conduct NCAGS exercises like Bell Buoy and Lucky Mariner where member nations represented by NCAGS staff and merchant marine community come together in order to jointly exercise civil military response to a global threat scenario to shipping.[32] It would be worthwhile to have suitable Naval reps from IN attend these exercises either as participants or observers. This would allow us to remain in tune with the current developments in this field. Based on experience gained in such exercises, we could have our own scenario based exercises.



  1. Books

Bagnasco, Erminio. “Submarines of World War II. Annapolis.” Maryland: Naval (1977)

Blair, Clay. Silent Victory: The US Submarine War Against Japan. Naval Institute Press, 2001.

Carter, Worral Reed. “Beans, Bullets, and Black Oil: The Story of Fleet Logistics Afloat in the Pacific During World War II. Washington.” DC: Department of the Navy (1953).

Dyer, George C. Naval Logistics. (USNI Press, Maryland) 1962.

Hughes, Terry and Costello, John. The Battle of the Atlantic, New York: Dial Press,1977.

Huston, James A. The Sinews of War: Army Logistics; 1775-1953. Vol. 2. Government Printing Office, 1966

Milner, M. (2008). The Battle That Had To Be Won. Naval History, 22(3), 12-21.

Nitobe, Inazō. Bushido, The Soul Of Japan: An Exposition Of Japanese Thought. GP Putnams̓ sons, 1905

Smith, Steven Trent. Wolf Pack: The American Submarine Strategy that Helped Defeat Japan. Wiley, 2003

Vego, Milan. Operational Warfare At Sea: Theory And Practice. Routledge, 2008.

Willmott, Hedley Paul. The Last Century of Sea Power: From Washington to Tokyo, 1922-1945. Vol. 2. Indiana University Press, 2010.


Hansen Kenneth P, Canadian Naval Operational Logistics: Lessons Learned, Lost, and Relearned? The Northern Mariner/le marin du nord, XX No. 4, (October 2010)

Hoffman, F. G. The American Wolf Packs – A Case Study in Wartime Adaptation JFQ 80, 1st Quarter 2016

Richard J. Smethurst, Japan, the United States, and the Road to World War II in the Pacific The Asia-Pacific Journal, Vol 10, Issue 37, No. 4, September 10, 2012


ATP-02.1 Naval Cooperation And Guidance For Shipping (NCAGS) – Guide To Owners, Operators, Masters And Officers Edition A Version 1 September 2014

Clem Lack, B.A., Dip. Jour., Public Relations Officer, Premier’s Department, Brisbane. Australia’s Merchant Navy, Read at the meeting of The Historical Society of Queensland on October 24, 1957

Department of Defense, Washington, D.C. World War II Informational Fact Sheets.1995, ED 406 277

Giesler Patricia, Valour at Sea – Canada’s Merchant Navy, Her Majesty the Queen in Right of Canada represented by the Minister of Veterans Affairs, 2005

Indian Naval Strategic Publication 1.2 Oct 2015, Ensuring Secure Seas – Indian Maritime Security Strategy, Integrated Headquarters, Ministry of Defence (Navy)

Linn, James, Supplying the Asia-Pacific Theater: United States Logistics and the American Merchant Marine in World War II (2016) University of New Orleans Theses and Dissertations. Paper 2167.

O’Neil, William D. Military Transformation as a Competitive Systemic Process: The Case of Japan and the United States between the World Wars. No. CRS-D0008616. A1. Center For Naval Analyses Alexandria VA, 2003.

RAN Doctrine 1 2010, Australian Maritime Doctrine

Dussault Sheyla, Naval Cooperation and Guidance For Shipping : Giving an old tool a new role in Canada’s Maritime Security, Royal Canadian Navy, Apr 09

United States Strategic Bombing Survey.(1947). The War Against Japanese Transportation, 1941-1945. [Washington]

Wigmore Greg “A Debt Of Shame” Repaid: Canadian Merchant Navy Veterans And Their Struggle For Compensation, Carleton University, Canada

4.Electronic Media/Websites










http://www.navweaps.com/Weapons/WAMJAP_ASW.php Japanese ASW weapons





Total no of words: 5373.

No of words excluding articles, footnotes, bibliography and digits: 4115

[1] http://www.usmm.org/ww2.html (accessed on 12 Sep 16)

[2] Milner, M. (2008). The Battle That Had To Be Won. Naval History, 22(3), 12-21. Retrieved from http://search.proquest.com/docview/203459633?accountid=132150

“The Battle of the Atlantic started on 3 September 1939 when U-30 sank the small British liner Athenia west of Ireland, and it ended on 7 May 1945 when U-2336 sank two small steamers in the North Sea off Newcastle, England.”

[3] George C Dyer,. Naval Logistics. (USNI Press, Maryland) 1962. p 119

[4] Worral Reed Carter,. “Beans, Bullets, and Black Oil: The Story of Fleet Logistics Afloat in the Pacific During World War II. Washington.” DC: Department of the Navy (1953). p 95, Chapter X

[5] Indian Naval Strategic Publication 1.2 Oct 2015, Ensuring Secure Seas – Indian Maritime Security Strategy, Integrated Headquarters, Ministry of Defence (Navy) p 73

[6] Richard J. Smethurst, “Japan, the United States, and the Road to World War II in the Pacific,


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