I'm assuming that the RN stands for Royal Navy but unsure of the CO.
Any thoughts?
Jim
I have found a reference to Arthur Ernest HIDER (5440) with HMS Racer (RNCO).
This was on the IWM website.
I found another reference to RNCO as Reporting Non-Comissioned Officer in a listing of abbreviations in a Canadian military book.
I can possibly explain more (with URL's) once I can do the search on my computer rather than iPhone.
Mike
Thanks Mike.
Further to my previous response, the Imperial War Museum link is:
[url=https://livesofthefirstworldwar.iwm.org.uk/lifestory/7691829]https://livesofthefirstworldwar.iwm.org.uk/lifestory/7691829[/url]
The other reference is to a Canadian book and in view of my recent finding below I now have doubts about RNCO abbreviation in this book being appropriate:
[url=https://www.canada.ca/content/dam/themes/defence/caf/militaryhistory/dhh/general/book-1986-bilingualism-forces-1-en.pdf]https://www.canada.ca/content/dam/themes/defence/caf/militaryhistory/dhh/general/book-1986-bilingualism-forces-1-en.pdf[/url]
However, could it be that RNCO stands for [b]Royal Naval College Osborne[/b] - your postcard is postmarked East Cowes.
See the topic in the following link: [url=https://www.greatwarforum.org/topic/134368-navl-cadets-1903-1921/]https://www.greatwarforum.org/topic/134368-navl-cadets-1903-1921/[/url]
Also Wikipedia: [url=https://en.wikipedia.org/wiki/Royal_Naval_College,_Osborne]https://en.wikipedia.org/wiki/Royal_Naval_College,_Osborne[/url]
The Royal Naval College, Osborne, was a training college for Royal Navy officer cadets on the Osborne House estate, Isle of Wight, established in 1903 and closed in 1921.
Great detective work, Mike.
Many thanks.
Jim
I would favour the Osborne College one. The heading looks like an address of the sender and the handwriting appears to be that of a young person