There are NO single occupancy cabins on any Carnival ship.
What Carnival offers is their Cat. 1A cabins. These are the lowest priced inside cabins on their ships. There are less than 10 of these per ship. They actually hold at least two people. Some of them hold 3 or 4, depending on whether there is a pull out sofa in the cabin. They are sold at 150% the double occupancy rate for the lowest price Cat. 4 (inside) cabin for one person in the cabin while every other category from Cat. 4 on up will charge a solo person in each cabin at least 200% of the double occupancy rate.
Most of these cabins are at odd places on the deckplan and may be significantly larger than other inside cabins. They can be to the very front of the bottom couple of decks or at the very back. There is usually one or two on Verandah Deck also. The Cat 1A cabin at the back of the ship right around from the Aft elevator is to die for. It is actually a lot like a little studio apartment with only one twin bed on the floor, a hideabed in teh ceiling and just an armchair and table. There is plenty of floor space and is quiet comfy and roomy.
As I said, Cat 1A cabins tend to be larger than a Cat 4 inside cabin. This is made possible because their location does not allow for the standard inside cabin configuration.
Some have two beds on the floor. However most have one twin on the floor and perhaps a bed tucked in the ceiling or against the wall. Some have just the one bed and a pull out sofabed.
On most Carnival ships, there are 4 Cat 1A's with porthole windows and 2 Cat 1A's with big picture windows. The others are inside cabins. Needless to say, these 6 cabins usually book up quick.
They are great for solo cruisers, children or teens and platonic friends. They are not for intimate couples because, unless you are sure of the configuration of the cabin you select, you may very well be sleeping bunk bed style which is not very romantic.
It is a great choice for anyone traveling alone because either you won't be in your cabin very much to miss the oceanview or, you will enjoy great sleeping b/c these cabins with no windows are DARK!!! Very nice for taking a mid-day nap.
As for noise, since they are at the very front and back of the ship, any noise from the anchor, engine is offset by the quiet hall, less foot traffic at the very back or front of the cabin decks.
I have been in several of the Cat 1A and now no longer select Cat 1A guarantee. I know what most (not all) of the Cat 1A cabins look like and I know the ones I like and don't care for.
(cruzin' solo by design)
Freedom ('09), Imagination ('08), Victory ('08), Destiny ('08), RCCL Navigator ('08), RCCL Majesty ('08), Glory ('07), Liberty ('07), Fantasy ('07), Destiny ('06), NCL PofAm ('05), Fascination ('04), Victory ('04), Fascination ('04), RCCL Voyager ('03), Fantasy ('99)