Yes, the K-IP works at sea, on the nearby coastline, up to more than 5 km! To visualise in detail the coverage of the K-IP on this area, look at our coverage model here. The simulations take into account a K-IP placed 1 meter above sea level. To ensure the dispersion of the radio waves of the K-IP, and to counter the effects of the waves, we advise you to wear the K-IP on your chest for example.