Autonomy in the shipping industry requires next level of situation awareness. By reusing IoT concepts we can address the requirements of this autonomy. IoT systems are however assuming good connectivity. In this paper we discuss challenges associated with wireless communications from IoT capable marine vessels to base stations on land. We present a review of use cases that remote controlled and autonomous ships need to be able to handle, along with their requirements on the communication. We also provide preliminary results from field measurements of channel conditions experienced aboard a vessel cruising in the Turku archipelago in Finland in winter conditions.