Basically the first-class had A,B and C-decks to themselves in the superstructure, besides the second-class areas housed at the aft end of the superstructure. On decks D,E,F first, second and third-class were housed down in these decks, each with a set area which the class was desinated to.
There were two dining saloons located on D-Deck. The first-class Dining Saloon was located amidships between the second and third funnels and the second-class dining saloon was located further down just aft of the fourth "fake" funnel. The only thing separating the second and first-class dining rooms was the galleys.
There has been much said about the 'locked gates' of the third class aboard Titanic. This of course is an emotive subject to some and story tellers love it.
I can relate to the third class being 'shut off' behind gates or barriers when serving with the Royal Mail company in the late 'fifties'
Serving as an Able Seaman on Royal Mails, Alcantara, we would leave Southampton and call in at Vigo in Spain and Lisbon Portugal, to pick up emigrants for South America. We would also call in at Las Palmas in the Canary Islands,mainly for cheap bunkers before proceeding across to Recife, Santos, Montevideo and Buenos Aires.
The third class occupied the accommodation for'ard, having the for'ard well deck for their open deck space including the after end of the foc's'le head. They were 'gated off' with no access whatever to any other decks onboard. The only access was through a steel door either on the port or starboard side of the forepart of the bridge which was always 'dogged' shut in case of heavy weather. This was also their only access to the boat deck. Had the ship foundered for any reason , I have always had a gut feeling that the same type of people would have gotten into the lifeboats first and the press would have had a field day.
The Alcantara and her sister ship the Asturias were three class ships and primarily on the South American service. The deck crew on the outward bound voyages would spend much of their time cleaning out hatches, dumping dunnage and sterilising hooks and chains etc, for the huge meat cargo's on the homeward voyage. A feature of these vessels were the hydraulic cranes used instead of derricks and the crew would have to operate these at every port as stevedores found them too unpredictable and dangerous.
Beaming up hatches and the laying of hatch boards would remind the emigrants who's accommodation surrounded the two forward hatches of why they were travelling so cheaply.
These were 'good jobs' for seamen, paying out good overtime and a good menu onboard with plenty of good steaks, the like of which I've never tasted better, anywhere else in the world!!
All the best,