The UK Chinook can be fitted with a hoist, (used to be the same mechanism as the Sea King) but not all aircraft fleet wide are fitted with hoists due to availability and servicing, but most deployed aircraft are hoist equipped.
The hoist fits over the right hand door and has a 250’ cable. To use the hoist without any bodily contortions, the step requires removal and replacement with a removal plug - other than that it’s a fairly easy fit/removal.
There are three issues with conducting SAR with a Chinook:
Firstly, although all crews are trained on the hoist, they are only current to a basic level at any given time, as it’s a secondary role. Also, they aren’t medically trained to the same level as SAR winchmen/winch Ops, which may be a consideration depending on complexity of task.
Secondly, downwash. Though it would have probably been fine with a ship the size of the Viking Sky, the Chinook downwash has been known to cause more problems than it solves; it’s not an answer for a 32’ yacht with no power.
Lastly, the door is designed for crew to enter and exit the aircraft, and is sized accordingly. It’s narrow and a major faff to get multiple casualties or stretchers in and out of.
Could a Chinook of helped out with the Viking Sky? Probably, it’s a big old vessel, the Chinook has good out of wind hover performance and can carry a fair few people. However, SAR is one of those tasks that can get out of hand very quickly. It’s best left to the specialists.
The OP then goes off into different directions and I’m unsure what he’s asking. The Chinook with a hoist is generally as good as the crew operating it, wherever that may be in the world, but as stated 100mph downwash is a disadvantage many of the SAR aircraft don’t have.