Not all boats, crews, sailing locations, or operators are created equal. There was a time where all the boats carried a belt and impeller at least in the spares with the tools to change them yourself or find a local to do it for a tip. Much of the BVI is so close to home and the materials so much better that most charters in the BVI never have to deal with it. In most other areas more than 10 miles from Tortola from Anegada to Grenada you should not expect to see a chase boat. You will either be finding someone local to you to do it or doing the fix to get home yourself. Never confuse the marketing brochure with island reality.