On the 26th May Alister left South Wales on the Dorelian, Captained by Duncan Macqueen, his first voyage. The Dorelian sailed from Swansea to join convoy OB-156 just off Pembrokeshire.
A ship such as the Dorelian may travel at 8 or 9 knots. It takes just over two weeks to cross the Atlantic to Canada, maybe two weeks to load up with cargo and of course two weeks to come back.
So that they could enjoy naval protection ships convoyed together with one or more escort ships. The convoy system had been introduced successfully in the Great (First World) War. To many it was counter-intuitive to put all the eggs in one basket but it was found to work and is statistically sound. However the U-boats adaption to hunt in packs improves the odds in their favour when they do find a convoy.
Convoy OB-156 comprised 11 merchant ships protected by HMS Folkstone. At this time Britain was only able to protect the ships at the start of their voyage out into the Atlantic so the convoy dispersed after three days about 800 nautical miles out from the UK.
Convoys were designated by a route code (OB in this case) and then an incremental serial number (156). The OB series of convoys took ships out of Liverpool heading for North or South America, ships from other UK ports would join up at designated meeting points in home waters.
This series of convoys started when OB-1 sailed on 7th September 1939. On 13th October the first OB convoy, OB-17 was attacked and two ships hit. By the time convoy OB-156 sailed with Alister on 27th May seven ships on OB convoys had been hit by U boats, the last one OB-74 on 17th January 1940.
So when OB-156 set out four months had passed and 56 OB convoys had sailed without loss. Maybe it did not seem too dangerous. Those on the convoys may think it cheeky of me to think that and suggest I might like to try it and see: but if you consider it dangerous in May 1940 then you will struggle for vocabulary soon after.
The Germans had already reached the coast of Norway and as Alister sailed they were becoming masters of France and a very big Atlantic coast. Now it really would become dangerous: in the next three months over 270 allied ships were to be sunk. By 1945 around 3,500 vessels were lost and more than 30,000 merchant sailors had died. Despite censorship I have no doubt every sailor would be aware of the threat.
In May 1940 OB convoys sailed South of Ireland because the U-boats came from Norway and Germany. Soon with the U-boat bases in France this was too dangerous and they would head out North of Ireland.
Luckily for OB-156 the U boats did not catch them. In fact they did not get an OB convoy for another five weeks, till 2nd July 1940, when they sunk the Athellaird in OB-176. Their first hit since January, but for the remaining six months of 1940 they attacked every second or third OB convoy hitting 32 ships.
That was to come, the Dorelian with Alister starting in OB-156 reached Montreal safely on 6th June 1940.
View OB-156 26/05/1940 in a larger map