Semi-Specific Sites feature a narrower range of information, often concentrating on a specfic navy, era, ship type, war, battle, etc.
Ship-Specific Sites feature information about a specific ship. Sites for ships that are now musems are listed with the museums.
Photo Sites the major content of these sites is photographic.
Official Sites for a variety of agencies. projects, etc. Some official sites are mixed in with the other categories.
Commercial Sites advertising sites for maritime/naval firms; these sites are only listed if they provide some free material of interest to the public. No endorsement of these companies is implied.