!5 -20% of the cost of a crewed charter is the industry norm - the crew are experienced professionals who make every effort to make your vacation the best possible experience, working both before and during your time on the boat and they depend on and have an expectation of a fair tip - depending on the service of course.
Crew make very little money if there is not a charter aboard, so the weeks they do have a charter are very important to the years income. Catering to every individual, anticipating needs, putting out great food, keeping the boat spotless, keeping everyone safe, having a smile and a perfect attitude are all part of the job - and it is not always easy - guests are often demanding and have little concept of simple boat etiquette and practices, having paid a substantial charter cost they occasionally treat crew a bit disrespectful or have no regard for the vessel and the work it takes to keep it safe and ship shape. The emotional dynamics alone that take place sometimes between the charter group themselves is always a tricky negotiation for crew when individuals share such a confined and unfamiliar space for a week.
!5-20% gratuity is not an unreasonable reward if the crew exercising their experience on many levels makes your vacation the best ever. Booking a return charter, because of their effort, next season is the best compliment you can pay as well.
I have had charter guests who over 30 years later are still some of my most valued friends.