Merchant Navy

And so his family is not particularly well off.

And in order to provide for his family and escape all of the horror of growing up in Manchester, he signs up with the British Merchant Navy, which is distinct from the British Royal Navy.

So the British Merchant Navy is a civilian volunteer service.

And

there

may be a couple of reasons why he signed up with the Merchant Navy as opposed to the Royal Navy.

My guess is that because the age of eligibility is one year younger, so you can start training at 16 and then deploy at 17, whereas it was 18 for the Royal Navy.

So he studies to become a radio operator with the British Merchant Navy and then ships off at the age of 17 in 1943 to serve in the Battle of the Atlantic.