Great!
Awesome.
Maybe 10-20% less carbs per hour. All dependent on gut tolerance and proclivity for reflux. Burping up stomach contents because you’re prone and breathing hard isn’t a fun or ideal experience.
The total magnitude of carb need may be substantially lower for swimming for most folks because the primary determinant of intra-workout carb recommendations is duration of workout, and most folks don’t go swim for 3+ hrs!