Ellermans built mainly 12-passenger ships, they produced postcards of each vessel for use by those on board. Usually these were based on photographs taken on initial trials. I never sailed with passengers so don't know if the cards were sold to the passengers or free-issued.
All of these Ellerman postcards were unsent and in a collection of photos that I believe came from an Ellerman Captain T.M. Williams, (Commodore?). I got them from a friend of a relative of the owner of the cards when the owner died and cannot be certain that it was Captain Williams. There are as you say twelve and I intend to psot the rest to Gallery ASAP