A convoy is a group of vehicles, typically motor vehicles or ships,
traveling together for mutual support and protection. Often, a convoy
is organized with armed defensive support. It may also be used in a
non-military sense, for example when driving through remote areas.
Arriving at the scene of a major emergency with a well-ordered unit
and intact command structure can be another motivation.[clarification
1 Naval convoys
1.1 Age of Sail
1.2 World War I
1.3 World War II
1.5 Post-World War II
2 Road convoys
Humanitarian aid convoys
2.2 Truckers' convoys
2.4 Storm convoys
3 See also
5 Further reading
5.1 Primary sources
5.2 World War II
5.2.1 Official history
6 External links
Age of Sail
Naval convoys have been in use for centuries, with examples of
merchant ships traveling under naval protection dating to the 12th
century. The use of organized naval convoys dates from when ships
began to be separated into specialist classes and national navies were
French Revolutionary Wars
French Revolutionary Wars of the late 18th century, effective
naval convoy tactics had been developed to ward off pirates and
privateers. Some convoys contained several hundred merchant ships. The
most enduring system of convoys were the Spanish treasure fleets, that
sailed from the 1520s until 1790.
When merchant ships sailed independently, a privateer could cruise a
shipping lane and capture ships as they passed. Ships sailing in
convoy presented a much smaller target: a convoy was as hard to find
as a single ship. Even if the privateer found a convoy and the wind
was favourable for an attack, it could still hope to capture only a
handful of ships before the rest managed to escape, and a small escort
of warships could easily thwart it. As a result of the convoy system's
effectiveness, wartime insurance premiums were consistently lower for
ships that sailed in convoys.
Many naval battles in the
Age of Sail
Age of Sail were fought around convoys,
Battle of Portland
Battle of Portland (1653)
The Battle of Ushant (1781)
The Battle of Dogger Bank (1781)
The Glorious First of June
The Glorious First of June (1794)
Battle of Pulo Aura
Battle of Pulo Aura (1804)
By the end of the
Napoleonic Wars the
Royal Navy had in place a
sophisticated convoy system to protect merchant ships. Losses of
ships travelling out of convoy however were so high that no merchant
ship was allowed to sail unescorted.
World War I
Main article: Convoys in World War I
In the early 20th century, the dreadnought changed the balance of
power in convoy battles. Steaming faster than merchant ships and
firing at long ranges, a single battleship could destroy many ships in
a convoy before the others could scatter over the horizon. To protect
a convoy against a capital ship required providing it with an escort
of another capital ship, at very high opportunity cost (i.e.
potentially tying down multiple capital ships to defend different
convoys against one opponent ship).
Battleships were the main reason that the British
Admiralty did not
adopt convoy tactics at the start of the first Battle of the Atlantic
in World War I. But the German capital ships had been bottled up in
the North Sea, and the main threat to shipping came from U-boats. From
a tactical point of view, World War I–era submarines were similar to
privateers in the age of sail. These submarines were only a little
faster than the merchant ships they were attacking, and capable of
sinking only a small number of vessels in a convoy because of their
limited supply of torpedoes and shells. The
Admiralty took a long time
to respond to this change in the tactical position, and in April 1917
convoys were trialled, before being officially introduced in the
Atlantic in September 1917.
Other arguments against convoys were raised. The primary issue was the
loss of productivity, as merchant shipping in convoy has to travel at
the speed of the slowest vessel in the convoy and spent a considerable
amount of time in ports waiting for the next convoy to depart.
Further, large convoys were thought to overload port resources.
Actual analysis of shipping losses in
World War I
World War I disproved all these
arguments, at least so far as they applied to transatlantic and other
long-distance traffic. Ships sailing in convoys were far less likely
to be sunk, even when not provided with an escort. The loss of
productivity due to convoy delays was small compared with the loss of
productivity due to ships being sunk. Ports could deal more easily
with convoys because they tended to arrive on schedule and so loading
and unloading could be planned.
In his book On the Psychology of Military Incompetence, Norman Dixon
suggested that the hostility towards convoys in the naval
establishment were in part caused by a (sub-conscious) perception of
convoys as effeminating, due to warships having to care for civilian
Convoy duty also exposes the escorting warships to
the sometimes hazardous conditions of the North Atlantic, with only
rare occurrences of visible achievement (i.e. fending off a submarine
World War II
See also: Convoys in World War II
Convoy Routes in the Atlantic Ocean during 1941
See also: Battle of the Atlantic
The British adopted a convoy system, initially voluntary and later
compulsory for almost all merchant ships, the moment that World War II
was declared. Each convoy consisted of between 30 and 70 mostly
unarmed merchant ships. Canadian, and later
American, supplies were vital for Britain to continue its war effort.
The course of the
Battle of the Atlantic
Battle of the Atlantic was a long struggle as the
Germans developed anti-convoy tactics and the British developed
counter-tactics to thwart the Germans.
The capability of a heavily armed warship against a convoy was
dramatically illustrated by the fate of
Convoy HX-84. On November 5,
1940, the German heavy cruiser Admiral Scheer encountered the convoy.
Maiden, Trewellard, Kenbame Head, Beaverford, and Fresno were quickly
sunk, and other ships were damaged. Only the sacrifice of the Armed
Merchant Cruiser HMS Jervis Bay and failing light allowed the
rest of the convoy to escape.
The deterrence value of a battleship in protecting a convoy was also
dramatically illustrated when the German light battleships (referred
by some as battlecruisers) Scharnhorst and Gneisenau, mounting
11 in (28 cm) guns, came upon an eastbound British convoy
(HX-106, with 41 ships) in the North Atlantic on February 8, 1941.
When the Germans detected the slow but well-protected battleship
HMS Ramillies escorting the convoy, they fled the scene rather
than risk damage from her 15 in (38 cm) guns.
The enormous number of vessels involved and the frequency of
engagements meant that statistical techniques could be applied to
evaluate tactics: an early use of operational research in war.
Prior to overt participation in World War II, the US was actively
engaged in convoys with the British in the North Atlantic Ocean,
primarily supporting British activities in Iceland. This was
discussed by John T. Flynn in his 1944 work "The Truth About Pearl
After Germany declared war on the US, the US Navy decided not to
instigate convoys on American eastern seaboard. US Fleet Admiral
Ernest King ignored advice on this subject from the British, as he had
formed a poor opinion of the
Royal Navy early in his career. The
result was what the
U-boat crews called their Second Happy Time, which
did not end until convoys were introduced.
See also: Pacific War
In the Pacific Theater of World War II, Japanese merchant ships rarely
traveled in convoys. Japanese destroyers were generally deficient in
antisubmarine weaponry compared to their Allied counterparts, and the
Japanese navy did not develop an inexpensive convoy escort like the
Allies' destroyer escort/frigate until it was too late. In the early
part of the conflict, American submarines in the Pacific were
ineffective as they suffered from timid tactics, faulty torpedoes, and
poor deployment, while there were only small numbers of British and
Dutch boats. U.S. Admiral Charles A. Lockwood's efforts, coupled with
strenuous complaints from his captains, rectified these problems and
U.S. submarines became much more successful by war's end. As a result,
the Japanese merchant fleet was largely destroyed by the end of the
war. Japanese submarines, unlike their U.S. and German equivalents,
focused on U.S. battle fleets rather than merchant convoys, and while
they did manage some early successes, sinking two U.S. carriers, they
failed to significantly inhibit the invasion convoys carrying troops
and equipment in support of the U.S. island-hopping campaign.
Several notable battles in the South Pacific involved Allied bombers
interdicting Japanese troopship convoys which were often defended by
Japanese fighters, notable Guadalcanal (13 November 1942), Battle of
Wau (5 January 1943), and the
Battle of the Bismarck Sea
Battle of the Bismarck Sea (2–4 March
At the Battle off Samar, the effectiveness of the U.S. Navy's escorts
was demonstrated when they managed to defend their troop convoy from a
much larger and more powerful Japanese battle-fleet. The Japanese
force comprised four battleships and numerous heavy cruisers, while
the U.S. force consisted of escort carriers, destroyers, and destroyer
escorts. Large numbers of American aircraft (albeit without much
anti-ship ordnance other than torpedoes) and aggressive tactics of the
destroyers (with their radar-directed gunfire) allowed the U.S. to
sink three Japanese heavy cruisers at the cost of one escort carrier
and three destroyers.
The German anti-convoy tactics included:
long-range surveillance aircraft to find convoys;
strings of U-boats (wolfpacks) that could be directed onto a convoy by
breaking the British naval codes;
improved anti-ship weapons, including magnetic detonators and sonic
The Allied responses included:
air raids on the
U-boat bases at Brest and La Rochelle;
converted merchant ships, e.g., Merchant aircraft carriers, Catapult
Aircraft Merchantman and armed merchant cruisers
Q-ships, submarine-hunters disguised as unarmed merchant ships to lure
submarines into an attack
more convoy escorts, including cheaply produced yet effective
destroyer escorts/frigates (as corvettes were meant as a stopgap), and
fighter aircraft (carried by escort carriers and merchant aircraft
carriers) that would drive off German bombers and attack U-boats
long-range aircraft patrols to find and attack U-boats;
improved anti-submarine weapons such as the hedgehog;
larger convoys, allowing more escorts per convoy as well as the
extraction of enough escorts to form hunter-killer support groups that
were not attached to a particular convoy
allocating vessels to convoys according to speed, so that faster ships
were less exposed.
They were also aided by
improved sonar (ASDIC) allowing escort vessels to better track
breaking the German naval cipher;
improved radar and radio direction finding allowing planes to find and
Many naval battles of
World War II
World War II were fought around convoys,
Convoy PQ-16, May 1942
Convoy PQ-17, June–July 1942
Convoy PQ-18, September 1942
Operation Pedestal, August 1942
The Naval Battle of Guadalcanal, November 1942
The Battle of the Barents Sea, December 1942
The Battle of the Bismarck Sea, March 1943
The convoy prefix indicates the route of the convoy. For example, 'PQ'
would be Iceland to Northern Russia and 'QP' the return route.
The success of convoys as an anti-submarine tactic during the world
wars can be ascribed to several reasons related to U-boat
capabilities, the size of the ocean and convoy escorts.
In practice, Type VII and Type IX U-boats were limited in their
capabilities. Submerged speed and endurance was limited and not suited
for overhauling many ships. Even a surfaced
U-boat could take several
hours to gain an attack position. Torpedo capacity was also restricted
to around fourteen (Type VII) or 24 (Type IX), thus limiting the
number of attacks that could be made, particularly when multiple
firings were necessary for a single target. There was a real problem
for the U-boats and their adversaries in finding each other; with a
tiny proportion of the ocean in sight, without intelligence or radar,
warships and even aircraft would be fortunate in coming across a
Royal Navy and later the
United States Navy
United States Navy each took
time to learn this lesson. Conversely, a U-boat's radius of vision was
even smaller and had to be supplemented by regular long-range
For both major allied navies, it had been difficult to grasp that,
however large a convoy, its "footprint" (the area within which it
could be spotted) was far smaller than if the individual ships had
traveled independently. In other words, a submarine had less chance of
finding a single convoy than if it were scattered as single ships.
Moreover, once an attack had been made, the submarine would need to
regain an attack position on the convoy. If, however, an attack were
thwarted by escorts, even if the submarine had escaped damage, it
would have to remain submerged for its own safety and might only
recover its position after many hours' hard work. U-boats patrolling
areas with constant and predictable flows of sea traffic, such as the
United States Atlantic coast in early 1942, could dismiss a missed
opportunity in the certain knowledge that another would soon present
The destruction of submarines required their discovery, an improbable
occurrence on aggressive patrols, by chance alone. Convoys, however,
presented irresistible targets and could not be ignored. For this
reason, the U-boats presented themselves as targets to the escorts
with increasing possibility of destruction. In this way, the
Ubootwaffe suffered severe losses, for little gain, when pressing pack
attacks on well-defended convoys.
Post-World War II
US Navy warships escort the tanker Gas King in 1987
The largest convoy effort since
World War II
World War II was Operation Earnest
Will, the U.S. Navy's 1987–88 escort of reflagged Kuwaiti tankers in
Persian Gulf during the Iran–
In the present day, convoys are used as a tactic by navies to deter
pirates off the coast of Somalia from capturing unarmed civilian
freighters who would otherwise pose easy targets if they sailed alone.
Humanitarian aid convoys
The word "convoy" is also associated with groups of road vehicles
being driven, mostly by volunteers, to deliver humanitarian aid,
supplies, and—a stated objective in some cases—"solidarity".
In the 1990s these convoys became common traveling from Western Europe
to countries of the former Yugoslavia, in particular Bosnia and
Kosovo, to deal with the aftermath of the wars there. They also travel
to countries where standards of care in institutions such as
orphanages are considered low by Western European standards, such as
Romania; and where other disasters have led to problems, such as
Chernobyl disaster in
Belarus and Ukraine.
The convoys are made possible partly by the relatively small
geographic distances between the stable and affluent countries of
Western Europe, and the areas of need in
Eastern Europe and, in a few
North Africa and even Iraq. They are often justified because
although less directly cost-effective than mass freight transport,
they emphasise the support of large numbers of small groups, and are
quite distinct from multinational organisations such as United Nations
A military convoy of Humvees leaving
Washington, DC the day after the
Inauguration of Barack Obama
Truckers' convoys consisting of semi-trailer trucks and/or petrol
tankers are more similar to a caravan than a military convoy.
Truckers' convoys were created as a byproduct of the USA's national
55 mph speed limit and 18-wheelers becoming the prime targets of
speed traps. Most truckers had difficult schedules to keep and as a
result had to maintain a speed above the posted speed limit to reach
their destinations on time. Convoys were started so that multiple
trucks could run together at a high speed with the rationale being
that if they passed a speed trap the police would only be able to pull
over one of the trucks in the convoy. When driving on a highway,
convoys are also useful to conserve fuel by drafting.
The film Convoy, inspired by a 1975 song of the same name, explores
the camaraderie between truck drivers, where the culture of the CB
radio encourages truck drivers to travel in convoys.
3. Einsatzeinheit of German Red Cross Freiburg Land prepares for a
march under special convoy rights
The Highway Code of several European countries (Norway, Italy, Greece,
Netherlands, Germany, Austria, Switzerland, possibly more) includes
special rights for marked convoys. They have to be treated like a
single vehicle. If the first vehicle has passed an intersection, all
others may do so without interruption. If other road users overtake
the convoy, they aren't allowed to split into the queue. Clear and
uniform marking has been required in court decisions for these rights
to apply. Operating such convoy usually needs special permission, but
there are exemptions for emergency and catastrophe intervention.
Common practice is, to operate with the same style of marking as NATO
STANAG 2154 marking plus country-specific augmentation listed
in Annex B to the STANAG.
Cold War with its high number of military exercises, the
military was the main user of convoy rights. Today, catastrophes like
large-scale flooding might bring a high number of flagged convoys to
the roads. Large-scale evacuations for the disarming of World War II
bombs are another common reason for non-governmental organization
(NGO) unit movements under convoy rights.
In Norway, "convoy driving" (Norwegian: kolonnekjøring) is used
during winter in case weather is too bad for vehicles to pass on their
Convoy driving is initiated when the strong wind quickly fills
the road with snow behind snowplows, particularly on mountain
passes. Only a limited number of vehicles are allowed for each
convoy and convoy leader is obliged to decline vehicles not fit for
the drive. Storm convoys are prone to multiple-vehicle
Convoy driving is used through
Hardangervidda pass on
road 7 during blizzards.
Convoy is sometimes used on road E134 at
the highest and most exposed sections during bad weather. On road
Saltfjellet pass convoy driving is often used when wind
speed is over 15–20 m/s (fresh or strong gale) in winter
conditions. During the winter of 1990 there was convoy driving for
almost 500 hours at Saltfjellet
Shoaling and schooling
Convoy of Hope
Workers' Aid for Bosnia
List of convoy codes and the similar List of
World War II
World War II convoys
Arctic convoys of World War II
The 1940 destruction of convoy SC-7
^ a b I.C.B. Dear and Peter Kemp, ed. (2007). "Convoy". The Oxford
Companion to Ships and the Sea. Oxford Reference Online. Oxford:
Oxford University Press. Retrieved 2008-12-07.
^ a b c d e Robb-Webb, Jon (2001). "Convoy". In Richard Holmes. The
Oxford Companion to Military History. Oxford Reference Online. Oxford:
Oxford University Press. Retrieved 2008-12-07. [permanent dead
^ Dixon, Dr. Norman F. On the Psychology of Military Incompetence
Jonathan Cape Ltd 1976 / Pimlico 1994 pp210–211
Convoy Archived 2011-07-19 at the Wayback Machine. from History
^ Conn, Stetson (1964). The Western Hemisphere, Guarding the United
States and Its Outposts. Washington, D.C>: Office of the Chief of
Military History, Department of the Army. US Government Printing
Office. p. 470.
^ "John T. Flynn on Roosevelt and Pearl Harbor by Laurence M. Vance".
Aid Convoy (charitable organisation) information on partners".
Archived from the original on 2007-04-28.
^ Annex B to
STANAG 2154, "Differences in National Marking of Columns
and Legal Rights" can be found on page 161 ff. of FM 55-30 Archived
2015-05-04 at the Wayback Machine. Linking to
STANAG 2154 directly
would be preferable. Anybody, who finds it in the public part of the
Internet, is welcome to improve this link.
^ Videos showing a convoy departure to the Elbe flood in Germany 2013
and the return from EU exercise FloodEx 2009 in the Netherlands
illustrate this kind of operation practically.
^ Kolonnekjøring, Statens Vegvesen (in Norwegian), published 19 March
2013, accessed 7 November 2015.
^ "Kolonnekjøring er vinterens utfordring". NAF. Retrieved 7 November
^ "Kollisjon under kolonnekjøring". NRK. 19 January 2008. Retrieved 7
^ "Vegvesenet går for billig veiløsningen på Hardangervidda".
Dagens Næringsliv. 27 October 2015. Retrieved 7 November 2015.
^ "Kolonnekjøring mellom Hovden og Haukeli". Fædrelandsvennen. 26
February 2015. Retrieved 7 November 2015.
^ Statens vegvesen Nordland (2000). Ferdsel under Polarsirkelen.
Statens vegvesen. ISBN 8299373816.
Allard, Dean C. "Anglo-American Naval Differences During World War I."
Military Affairs: The Journal of Military History, Including Theory
and Technology (1980): 75-81. in JSTOR
Crowhurst, R. Patrick. "The
Admiralty and the
Convoy System in the
Seven Years War." The Mariner's Mirror (1971) 57#2 pp: 163-173.
Gasslander, Olle. "The convoy affair of 1798." Scandinavian Economic
History Review 2.1 (1954): 22-30. abstract
Herwig, Holger H., and David F. David. "The Failure of Imperial
Germany's Undersea Offensive Against World Shipping, February
1917–October 1918." Historian (1971) 33#4 pp: 611-636. online
Lewis, James Allen. The Spanish convoy of 1750: heaven's hammer and
international diplomacy (Univ Press of Florida, 2009)
Syrett, David. "The Organization Of British Trade Convoys during the
American War, 1775–1783." The Mariner's Mirror (1976) 62#2 pp:
Thompson, F. J. "The Merchant Ship in Convoy." The RUSI Journal 79.513
Connor, Guy, and Jeffrey L. Patrick. "On
Convoy Duty in World War I:
The Diary of Hoosier Guy Connor." Indiana Magazine of History (1993).
World War II
Edwards, Bernard. The road to Russia: Arctic convoys 1942 (Leo Cooper
Forczyk, Robert. Fw 200 Condor Vs Atlantic Convoy, 1941-1943 (Osprey
Hague, Arnold. The allied convoy system, 1939-1945: its Organization,
Defence and Operation (Naval Institute Press, 2000)
Kaplan, Philip, and Jack Currie. Convoy: merchant sailors at war,
1939-1945 (Aurum Press, 1998)
Middlebrook, Martin. Convoy: the Battle for Convoys SC. 122 and HX.
229 (Allen Lane, 1976)
Milner, Marc. "
Convoy Escorts: Tactics, Technology and Innovation in
the Royal Canadian Navy, 1939-1943." Military Affairs: The Journal of
Military History, Including Theory and Technology (1984): 19-25.
O'Hara, Vincent P. In Passage Perilous: Malta and the
of June 1942 (Indiana University Press, 2012)
Smith, Peter Charles. Arctic Victory: The Story of
Convoy PQ 18
Winton, John. Convoy, The Defense of Sea Trade 1890–1990, 1983.
Commander in Chief, United States Fleet, "
Convoy and Routing."
Washington, 1945. 147 pp., online
Wikimedia Commons has media related to Convoys.
Lists of convoy prefixes for both World Wars
Convoy web – a comprehensive analysis of certain naval convoy routes
Aid Convoy – a humanitarian aid charity running convoys