Complex sentence: Since the island can be accessed by boat or small plane only, a regular ferry service runs from Pine Island Marina (the "Island Girl" charter service) at two hour intervals-serving both tourists and locals who own neither boats or airplanes.
Split into simpler sentences: Since the island can be accessed by boat or small plane only. A regular ferry service runs from Pine Island Marina, the "Island Girl" charter service, at two hour intervals, serving both tourists and locals who own neither boats or airplanes.