As an example, we just got back from the BVI. We chartered a Moorings 50.5. This was my 6th charter but this boat had some systems I had not had before including a genset and air conditioning. The ac packed up the last night. No big deal as the weather was nice. When we returned the boat the next day, I reported the problem to the checkout person. She said that happened regularly and there was a simple procedure to reset it. She said they had talked many charterers through it. Unfortunately, we were in the Bight and there was no cell service with base. It would have been nice to know ahead of time. Before anyone says it, yes, there was a manual on the boat but I did not read it. If I had had a copy before leaving home, I probably would have looked through it. BTW, I am a retired pilot so I can relate to some of the previous posters.
Lew