Quote:
They would be one in the same. SS= Steamship, RMS = Royal Mail Ship.
Yes, maybe, but we might have to "split hairs" again.

Officially, and with great prestige, any vessel that was awarded a mail contract, took on the title RMS = Royal Mail Steamer
In a quirk of curiosity, we have the "RMS Titanic"
with her lifeboats with the livery of "SS Titanic"
I'll let someone else explain.
Having the title "RMS" was seen as a mark of quality and a competitive advantage, because the mail had to be on
time. In the 1860 CDSPCo contract there was a penalty clause of £1 1s 4d for every minute's delay. The White Star
Line sisters RMS Olympic and RMS Titanic were Royal Mail Ships.
S.S. stands for Steam Ship and is the internationally accepted standard for a steam driven vessel as was RMS
Titanic.
The Lifeboats would carry SS rather than RMS because there MIGHT have been a later cruise when Titanic was
NOT under Royal Contract to carry the mail.
Source(s):
former US Naval Officer, History Teacher, and friend of the Royal Navy
I believe the Lusitania was under royal mail contract from
her commissioning hence RMS.
Not trying to be a smart bottom, but to some
may be of interest
