If you charter a power boat in the British Virgin Islands, you are going to use a lot more gas than a sail boat. How much should you budget for it?
These people discuss how much fuel they used on a Moorings 474. It sounds like between 107-150 gallons/week depending on how far you go and whether you run the AC or not.
So you should budget about $500-750 for gas for a week.
If you charter a sailboat, you should ask your charter company if you will need to pay for the fuel you used when you return the boat. Some charge, some don’t.
You should also always ask the charter company as each boat is different. Not all boats will use the same amount of fuel as the Moorings 474. Any body else have experience on other boats? Is it similar?
(By the way, the Moorings 474 is a very roomy boat compared to any sailing catamaran you are likely to charter. If I was taking down 4 couples, I would look at chartering it instead of a sailing catamaran just for the room.)