Clogged strainers are something that you need to be able to deal with. I have found plastic bags, rags, seaweed, jellyfish ect.. clogging the strainers. I have also found mussels growing in hoses and just plain dirty strainers that obviously were not cleaned on a routine basis. The later would be on the charter company. It’s always a good idea on the boat briefing to have the briefer show you the strainers and check that they are clean.
The OP’s problem could be something he picked up or it could be a maintenance issue that the charter company owns. From his description of the call to the charter company I suspect they are aware of the issue and it might be on them. The AC unit might be old and simply pulling more amps than the spec and the charter company is waiting for some down time to pull it.