Fionn101
The distance varies from where you coast out. You may have 100 miles to run but it may be only 40 miles from the shore. The continental shelf is a clue; that's where the offshore oil is. That can vary from being 200 miles, China, or on the doostep, the North Sea.
One does not stay in a ditched helicopter unless it is designed to float, ie the Sikorsky S61. Years ago they water taxied a ditched BV 234 (Chinook) to a platform but apart from that the aircraft is abandoned fairly rapidly. Offshore helicopters have flotation devices. Years ago they had pontoons, now smaller ones have bags that look like pontoons when they are inflated. Large helicopters have them streamlined on the the fuselarge or concealed within pop-out doors. They are only designed to keep the aircraft upright so that it can be abandoned safely. Without them, as the engines and gearboxs are at the top, it would almost certainly turn turtle as soon as it arrived. The liferafts, at least two of them, are designed to float so they are a better bet than a helicopter, which is not.
FantomZorbin
I was under the impression that the executive branch of helicopter travel had carried him. I would agree. I once had a terrifying ride in a Bell 47 from Nicosia to Akrotiri and I swore blind that I would never step into any helicopter below four tonnes again.