Convoy in Bedford Basin, Halifax, April 1,1942.
|Department of National Defence
/ National Archives of Canada, PA-112993.
There are two main reasons for grouping ships in a convoy: first of all,
over such a wide area as the Atlantic Ocean, a single group of some forty,
tightly packed ships is harder to locate than several, scattered crafts.
In addition, the number of warships required to protect a convoy is obviously
much lower than what would be needed if every single ship had her own
The convoy system had proven itself to be a valid concept during WWI.
When the war broke out in September1939, shipping by convoys was rapidly
organized. The first convoy, HX-1, sailed from Halifax on September 16th
for an uneventful crossing. As war went on, convoys got to be more frequent
and larger. The largest of all, HXS-300, was made up of 167 ships.
Great Britain required a very wide range of goods. Troops had to be carried
overseas as well as all kind of military equipment - tanks, various types
of vehicles, fuel, weapons. Food, lumber, building materials for barracks,
and raw materials for the industry also came by boat. Plus all those goods
that were already the object of a regular trade between the British Isles
and North America before the war.
|Call Letters of Trans-Atlantic
||fast convoys (9 knots or over)
sailing from Halifax or New York
||slow convoys (under 9 knots) sailing
from Sydney, Nova Scotia, Halifax or New York
|| westbound convoys sailing from
Great Britain to North America
||slow westbound convoys sailing
from Great Britain to North America
|Call Letters of Coastal Convoys:
||Boston to Halifax
||Halifax to Boston
||Sydney to Quebec City
||Quebec City to Sydney
The faster a ship can cross the Ocean, the less risk she runs of being
sighted and attacked by U-boats. But a convoy cannot be faster than its
slowest member. The earlier convoys were too fast for older ships, which
had to strain their engines to keep up with the other freighters. The
slightest mechanical problem forced them to pull out of the convoy, thus
becoming an easy target. To solve this problem, a two-speed system was
implemented: fast convoys were still formed in Halifax harbour, but, starting
August 15th, 1940, slower convoys regrouped in Sydney. In 1941, fast convoys
left every six days and made the crossing to Great Britain in 13 or 14
days. Slow convoys left every six days as well but took up to 16 or 17
days to sail across the Atlantic. The meeting point was moved south to
New York in September 1942.
Cruising Order of fast convoy HX-202,
August 1942. It includes names of ship, countries where registered,
cargo, and port of destination.
|Canadian War Museum, 198700068-008
The forty - or so - ships that make up a convoy are positioned within
a grid: there are nine columns, 920 metres apart, and in each column five
ships, 550 metres apart. Ships carrying dangerous cargoes, such as gas,
fuel, explosives are placed in the centre, the position that affords the
most protection against enemy torpedoes. A convoy commodore, in most cases
a retired naval officer, is on board one of the merchant ships to take
defensive measures as required and ensure coordination with the escort.
Naval authorities select the route, avoiding concentrations of U-boats,
which crisscross the Northern Atlantic. Once the convoy has sailed off,
it is joined by destroyers, corvettes and frigates, which position themselves
on the periphery. A command ship precedes the convoy, while other escort
ships take place on the flanks and astern of the convoy, in order to form
a screen against submarines. Escort ships must keep their relative positions
while making zigzags that allow them to sweep as broad an area as can
be with the ASDIC detection system. At the end of the route, merchant
ships leave the convoy in a pre-set order and continue towards their final
destination, whether in England, Scotland or Northern Ireland.
A Dangerous Job
Position of merchant ships with
escort made of a destroyer and three corvettes.
Between 1939 and 1943, even the Allies' most extreme measures were not enough
to ensure an efficient protection against U-boat attacks. Often at night,
an explosion signalled that a merchant ship had been hit. The sailors aboard
those vessels were well aware of how dangerous their work was. They knew
they were targeted by enemy torpedoes. They also knew that some cargoes
meant a sure death: a torpedoed tanker would blow up, a freighter carrying
iron ore would sink before the men had a chance to escape.