Re: Trusting someone to take a watch
We've learned the hard way that you've got to choose wisely.
I've had a highly qualified 100 ton master sign on for an offshore passage with undisclosed medical problems that put him down for the count. I've had good coastal sailing buddies that I thought were reliable decide to have a couple of beers before departing on a rough passage and get sick and sleep through their watch.
When someone lets you down on a passage, others have to fill in and run with less sleep reducing safety for all. Yea, stuff happens, but the above cases were self induced.
Some of the best advice I've received is from a doctor who does a lot of offshore passages. He treats his crew like part of the equipment. He dictates what they eat, what they drink, and when they sleep. He wants their medical history. If they don't like his rules they don't go.
There are only a handful of people I want to do a passage with. I admire those who can figure this out on the fly with new people (but based on my experience with selected "friends" maybe you're better off).