If you are planing a trip over water do the maths first. If you take the short crossing, it is 18.25nm. What height do you plan, what is typical wind, what is your aircraft's glide performance. For my aircraft I am typically out of gliding range for 90sec. Do the same for the north sea and the numbers are not so good.
Do not assume you will be able to get into a dingy unless you have had specialist training. Tests done by Plymouth Uni showed that almost nobody without training will get in in open water. The tests were done using fit young students
who were expecting to get wet, not your old overweight average PPL who will suffer temperature shock from a nice warm cockpit to UK sea temp.
I keep my crossings as short as possible and fly as high as I can.
Rod1