This article concentrates on aspects of marine technology such as fish cages, ships, sea structures, and marine operations. It addresses net cages and closed-containment fish farms through sloshing while discussing both displacement and high-speed vessels. The ship topics under consideration include CO2 emissions in waves, dynamic instabilities, whipping and springing, maneuvering in waves, and sloshing-induced slamming in prismatic LNG tanks. The considered sea structures include offshore platforms used for gas and oil exploration and production and for renewable energy. The article also discusses lowering and lifting of objects through the free surface from ships and addresses the accidental dropping of pipes during lifting operations from a vessel onto drilling rigs. The emphasis is on simplified theoretical modelling and scaling of model tests.