Joe

In this case, it's not Thomas that's in doubt but (the) Andrew!

Regards

p.s. The only guide to Naval slang I have to hand (Jackspeak) was published in 1989 and says of "Grey Funnel Line":

Traditional in-house nickname for the sea-going part of the Royal Navy and therefore a useful alternative to "the Andrew" in that respect. Also the title of a super book by Cyril Tawney containing the words of many matelot ditties

The author knew wherof he spoke.

Regards