The Minhat Yishak (Rav Yishak Weiss, 1901-1989) addresses the situation of people who live on an island and thus frequently travel by ferry through waterways. He writes that since the ordinary mode of travel for such people is by ferry, and this is how they get to the places they need to go on a day-to-day basis, they do not recite Birkat Ha’gomel after a ferry ride, even if the ride entails a trip of 72 minutes or longer. Since this is their normal, everyday practice, and Birkat Ha’gomel is required only after an unusual situation of danger, people in this situation do not recite the Beracha. Rav Shemuel Pinhasi (contemporary) adopts this ruling in his work Ve’chol Ha’haim (p. 47; listen to audio recording for precise citation). He gives the example of the city of Venice, where the only way to travel from one place to the next is by ferryboat. Since ferry travel is the ordinary, day-to-day means of travel, people who live in such places would not recite Birkat Ha’gomel after a trip in a ferry. Summary: People who regularly travel by ferry do not recite Birkat Ha’gomel after a ferry trip.