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 escort.
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 Convoys: |
| HX: |
fast
convoys (9 knots or over) sailing from
Halifax or New York |
| SC: |
slow
convoys (under 9 knots) sailing from
Sydney, Nova Scotia, Halifax or New
York |
| ON: |
westbound convoys sailing from Great
Britain to North America |
| ONS: |
slow
westbound convoys sailing from Great
Britain to North America |
| Call Letters
of Coastal Convoys: |
| BX: |
Boston
to Halifax |
| XB: |
Halifax
to Boston |
| SQ: |
Sydney
to Quebec City |
| QS: |
Quebec
City to Sydney |
Convoy Organization
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.
Position
of merchant ships with escort
made of a destroyer and three
corvettes. |
| |
|
A Dangerous
Job
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. |
Canada in WWII
