Warships of a nation (4)
(Other definitions for navy that I've seen before include "Colour; fighting force" , "Dark shade of blue" , "Nation's warships" , "military arm" , "A dark blue; service" .)
(Other definitions for fleet that I've seen before include "Fast; London street, old prison" , "Group of ships, aircraft etc" , "Number of vehicles" , "Navy - quick" , "Swift like naval force" .)