It is customary and expected to tip your crew, as gratuities represent about half of their income. The gratuity amount is usually 5% - 15% of the charter cost when budgeting your holiday make sure that this cost is included in your calculation. Crew members remain ready to help you in every possible way and time during your holiday and do a very hard job. Gratuity is just another way of saying "thank you" for taking good care of you.