The National Library of Wales has a large collection of charts, mostly modern Admiralty and commercial charts, but also antiquarian charts. Nautical charts (also known as marine or hydrographic charts) are maps primarily intended for navigation at sea. They should provide sailors with clear, correct and up to date information e.g. coast lines, depths, and locations of submerged rocks, to help plan, plot and navigate a safe course on the water.
Designed to be working documents, charts would often have been amended and written on, and therefore would have been discarded when out of date or damaged. As a result, they are much less likely to have survived than ordinary maps.
Here is a selection of digitised Nautical Charts: