I'm a bit of a half empty sort when it comes to these guesstimates. i would consider a worst case scenario: high winds head
, on big waves, one motor
overheats etc etc. Remember too that a 200 nm trip is more than that because you will not travel in a straight line no matter how hard you try to. I would budget
an average of 4 knots and a minimum consumption
of 6lph. That's 300 litres for the trip. It might be less if you can sail or motorsail. If you have a fuel guage, iI would look to see how far you've travelled when the tanks
are half full. If it's not more than half way, go back. But fuel guages are not the most accurate of devices.
This might sound like overkill, but think of the worst case and the consequences. Are there not places you can stop on the way? Remember too that you might need to travel overnight (2 nights) and that adds another layer of complexity.