Those of us with ancestors from Cardiganshire are very lucky to have the Ceredigion Archives as a resource. On two occasions I’ve contacted them with a query and both times the researchers have answered my questions and more, and are very helpful indeed.
The url for the website is http://archifdy-ceredigion.org.uk/ I do find the website a little cumbersome to work with, but when I searched for the ships I was interested in I did find them fairly easily.
Of particular help to me on my second query were the shipping records available for Aberystwyth. These records opened up a whole new family branch of Clayton mariners. It also put me in touch with a distant cousin, which was a lovely bonus. The archives has a wealth of information, so do contact them if you have queries in the area.