The National Library of Wales blog with the #LoveMaps tag has has features on;
- Welsh waters, World waters. An overview the Library’s collection of marine charts dating from 1800.
Crew List Index Project - was set up to improve access to the records of British merchant seafarers of the late 19th century and has gathered the largest database of entries from crew lists .............
Lighthouse Personnel in England and Wales and the Channel Islands 1841-1910. Includes;- Table of Keepers; Table of Stations by county; Location map of the lighthouse sites.
Welsh Mariners by Dr Reg Davies---includes a searchable database of over 17,000 Welsh born (or Wales resident) Master mariners, mates and engineers who held certificates of competency or service; in practice it is an index of men active from 1850 to 1945 in the merchant navy.
Swansea Mariners by Bryan Richards --- periods 1861 to 1871 and 1890 to 1894, a database of ratings such as un-certificated officers, bosun, able seaman, ordinary seaman, boy, cook, steward, etc in Glamorgan Carmarthenshire, Pembrokeshire, Cardiganshire, or from around the world. There are 32,000 detailed entries (9/2006).
Index to Ships in Books - Peter McCracken's site with over 100,000 ships' names in the index
Ships in Port in 1881 - on Bob Sanders' site
See also the UK Merchant Marine page on Genuki