The ship’s crew and officers (whether on warships, merchant ships or passenger ships) were generally kept very busy when at sea.

Most of the time of the ship’s crew was spent on maintenance of the ship. Maintenance fell under several headings:

Cleaning: The ship was cleaned every morning, decks swabbed and holystoned, paint work cleaned down.

Pumping: All ships leaked somewhat, worse in bad weather. Depending on how fast water came in, the pumps would need to be manned every so often to get it back out.

Coating wood: Wood lasts longer if coated with paint, varnish or oil. Most of the wood from which wooden warships were made would be coated. Coating does not last and needs to be renewed. Every day there would probably be some of the crew involved in stripping, sanding, painting, varnishing, or oiling some part of the ship.

Repairing wood: Timbers could get damaged by rot (caused by the collection of fresh water on wood) or by various stresses or impacts. Damaged wood would be cut out and new wood scarfed in by the carpenter and his mates.

Coating rigging: Almost all the rigging of these European ships was made of hemp rope. Hemp deteriorates quickly unless protected. The protection used was "parcelling" (wrapping the line with canvas), "serving" (wrapping the canvas with smaller line) and "tarring" (coating the whole parceled and served line with tar). All of the standing rigging was protected by tar, and this needed to be replaced fairly frequently. On almost all day watches, some of the watch would be engaged in tarring down the rigging.

Repairing / replacing rigging: The running rigging was generally not tarred, as this made it stiff and difficult to handle. The hemp rope used to make this rigging deteriorated (especially in intense sunlight). Running rigging had to be replaced fairly frequently. Whipping, splicing, and reaving new running rigging was a common maintenance task.

Standing rigging, protected by tar, lasted longer, but it had to be replaced eventually. The ratlines by which sailors went aloft were made of small diameter line, which did not last so long. They were also a safety hazard if they rotted and broke when men were climbing them. Replacing the ratlines was called "rattling down" and it was a fairly common maintenance task. Making replacement standing rigging, and parceling and serving it was a fairly common maintenance task. Some of the standing rigging would be further wrapped in "baggywrinkle" to protect the sails from wear where they chafed against standing rigging. Baggywrinkle wears out fairly quickly (its job is to wear out rather than have the sails wear out), so some of the crew would often be deployed in making new baggywrinkle (made from old worn out rigging) or replacing old baggywrinkle with new.

Chipping iron: Iron, in the wet and salty conditions at sea, is very prone to rust. Almost all iron was coated with paint, to protect against rust, but moisture often got under the paint and caused rust to start. Chipping the rust off (with a "chipping hammer") and then repainting the iron was sure to employ some of the crew on every day watch. Chipping and repainting the cannon balls, was often seen as one of the most boring and unpleasant tasks at sea.

Polishing Brass: Brass has an advantage at sea over iron in that it does not rust, but it does tarnish, turning a green "verdigris" color unless polished. The brass, (binnacle, ship's bell, various portholes and hardware, sometimes some of the cannon) would be polished every day.

Repairing sails: Sail canvas (usually of flax or cotton) does not last forever. Old sails could be patched or repaired or strengthened, but also the sailmaker, his mates and some of the able seamen would usually be working on new replacement sails as well as sail repair every day.

That covers most of the maintenance tasks involved in looking after the ship. There were other tasks involved in maintaining the crew (getting water, stowing supplies, cooking meals, etc.), tasks involved in maintaining combat effectiveness on warships (practicing with the guns, practicing sail handling and maneuvers), and tasks involving maintaining the passengers on passenger ships.

Besides maintenance, there were many tasks to do with sailing the ship. One or several of the crew would be at the wheel, steering the ship at all times. The crew might be called on to adjust the set of the sails by adjusting braces, sheets and tacks if the wind or course shifted. If the wind increased or decreased the crew would take sail or set more sail (and / or reef or shake out reefs). The officers would supervise the crew, navigate (cast the log regularly through each watch, note the speed and compass course sailed, plot the “dead reckoning” position on the chart, take sun sights every noon (co-ordinated with a chronometer after about 1800) to get a “fix” on the ship’s position (both in latitude and longitude once chronometers became common), supplement this with star sights at dusk and dawn to get additional confirmation of position, possibly take lunar sights (though not that common, as the mathematics are very complicated), adjust the course, adjust the rig and sails to account for changing winds and conditions.

The sailors and officers would mostly be divided into two “watches” (port and starboard). Each watch would be on duty for 4 hours and then off for 4 hours.

The day watches would be filled with work. The night watches would be less occupied, with only the helmsmen, officers, and lookouts working unless the sails needed to be adjusted. The rest of the night watch could sleep on deck, as long as they were ready to wake up and act quickly if sail handling was required.

As well as watch standers there were some “idlers” who only worked during the day and got an uninterrupted sleep all night long. These were the cook, and (on warships) some of the specialist petty officers such as the sailmaker, carpenter, gunner, etc.

If the ship carried passengers, there was usually an area of deck reserved for them to take the air, there were fairly formal dinners (for the better class of passenger), but generally, they were left to amuse themselves.

Actually a lot of the time could and would generally be spent on deck. Any actual setting of the sails or adjustments that would need to be made would only happen intermittently so there was more then enough time and space to look out and watch the endless expanse of water, then cross the Quarter Deck and look at the same thing on the other side.

Beyond that though there was always mending and cleaning to be done for the crew. Officers would stand watches, be responsible for educating Midshipmen, and drilling the men of their divisions. along with the administration of discipline as required.

There were also games as always, though over time and in different navies gambling itself was banned, but dice and cards were always popular.

Reading and writing for those who could, usually the officers in their ward room could take up time, most ships kept at least some sort of library and letters written could be sent on when they met another ship.

And of course singing and dancing were always popular, work shanties were just a small portion of the music to be found aboard a ship.

The Officer's Ward Room actually did serve as amongst other purposes as their lounge.

The film Master and Commander actually does a fine job of portraying shipboard life, gives a good feel of how insular their world could be: https://www.youtube.com/watch?v=iAguied64J0