It isn’t like you need to charge around at 50 mph on a 35-foot sport yacht. But let’s say you’re 50 miles from home port. The water’s calm, but radar shows a storm approaching. You have a little more than an hour to beat it home. On our test boat, with twin MerCruiser 496 Mags, you could make it – with about 160 gallons (210 gallon capacity) of fuel to spare.