I am not sure if I am posting this query in the right place actually.
John Thomas Aspinall was born in 1907 on a boat near Wigan - his father was also a Boatman.
My friend has a document indicating that on 26/1/1943 he was engaged for training at the Royal Navy Training Establishment, H.M.S. Gordon.
On 9/3/1943 he was discharged from this training 'Passed out A.B.'
The next entry dated 12/5/1943 shows an engagement in Glasgow - Fireman and 'Trimmer'? This form passed down to my friend is attached.
In addition there are 2 cards on the Find My Past under the 'Britain Merchant Seamen 1918-1941' for John Aspinall - correct date of birth.
One seems to be either/or Health or Unemployment Insurance Card - undated - showing his occupation as Fireman.
The other - dated 5/3/1943 - 'Declaration to be made if need arises' - showing the name of the ship as H.M.S. Gordon.
https://search.findmypast.co.uk/record?id=GBOR%2FBT364%2F085%2F284&parentid=GBOR%2FMERNAVSEA%2FBT364%2F5973Were Merchant Seamen co-opted into the Navy please after undergoing a short period of training? Or trained 'just in case' they were needed?