access alert authorities authority availability available boat boating-control communicating communication control deployment equipment fast flag foam froth Hong-Kong law law-&-order light movement naval observation on-duty on-the-job order patrol patrolling power presence regulations responsibility responsible sea secure security speed transport wake water watercraft white boating cat Catamaran catamarans city city-skyline cityscape deck dock docked enjoyment guard-rails lines luxurious luxury moored mooring motorised multihulled multihulls outdoor-sport outdoors parallel-hulls pleasure-craft powerful rails recreation recreational-sailing relaxing river river-mooring safety sea-going-vessel ship under-sail waves wealth