My deposits are somewhat tiered and that is where the refunds get fuzzy. It is $100 per day to book dates on the calendar. That is for the entire boat, so $35 per person. When you book those dates, I reserve the slip in the marina where we are running. So basically, I spend that $100 per day immediately to make sure you can go diving where you chose. If you cancel and I can get that money back, I will refund it. If I can't, I don't.
As to the actual charter costs. I refund if I don't run and it isn't your doing. Weather, mechanical, whatever it may be, I refund the money. If you went out drinking after Saturday dives and you are too hung over Sunday, it isn't getting refunded. That happens more than it should.
Last year was really bad for weather. We got blown out a lot. Financially, it can be rough. Especially when you get the oversize permits and trailer the boat 700 miles only to get blown out for half of the trip.