I remember seeing a YouTube video from Hoegh Autoliners where it took them 16 hours to load 1000 cars, and that was considered a short time frame in the video.
Yes.
People often forget that a ship will also unload as well as load in a port and it all takes time.
Shanghai is without doubt one of the most efficient ports in the world for turning a ship round (one of the main Japanese ports would probably take the crown). It's probably a reflection of how many teams of drivers are thrown at the problem but the organisation, speed and discipline of the teams just make it an incredible spectacle of continual movement controlled by whistles, wands and horns. However, a slight hiccup ( a car with a flat, a car that won't start) can derail the whole process. An eerie silence immediately descends as the snake quickly halts, the problem gets sorted and slowly the movement restarts. It takes time for the former rythmn to be reestablished and back up to its former speed.
All the drivers wear a uniform that is designed not to snag or mark - no buttons or metal studs. The cars are parked a specified (small) distance apart that means that they cannot be accessed once parked. Every car will be lashed to the deck to prevent movement. In the event of heavy seas and a lashing breaking the loose car's movement will be restricted by the close proximity of its neighbours limiting damage to a small localised area and not endangering the ship. Each car will be loaded according to a pre-arranged plan in batches designed for easy unloading. (It's no use arriving at a port and having to move 1000 cars to get at the 200 that need unloading). The loading plan will have been sent to the ship prior to its arrival so that the ship can be safely ballasted for the rotation. On arrival the dock plan and ship plan are compared to ensure everyone is working to the same sheet of music and then the ballet commences. The ship's crew keep an eye on the condition of vehicles as they come aboard. There are lots of rules covering damage and the Captain will ensure that the ship is in "ship-shape condition" in all respects before loading begins. This includes everything from the the crew's qualifications to deck cleanliness. If a single member of the crew's numerous qualifications are missing or expired, in the event of any damage, howsoever caused to the vehicles, it will be argued that the ship was not seaworthy and should not have put to sea thereby laying the ship liable. The shipping companies operational procedure manuals are thick and well thumbed. Different companies have slightly different procedures but in the main they are much of a muchness in that the safe handling of the cargo is of prime concern.
Loading, particularly in smaller less frequented ports can be troublesome. Here you are more likely to encounter poorly trained stevedores. They are slower (although they invariably drive too fast!) more likely to damage vehicles, or the ship, and the lashings applied need to be more closely scrutinised.
The larger the ship or the load the more likely 'extra' stevedores will have been employed and the more likely 'temporary' unskilled workers will have been signed on to complete it - the ships crew are looking for signs of this and are ready to document it to protect the ship from the inevitable damage claims.
It's a tricky business which is why once a car company is happy with its handling agents, its shippers, its ports and shipping companies it is very unlikely to risk a change.