One of my favourite reference books for maritime research in the UK was compiled by a number of librarians and archivists who work in this specialist field.
Although it was last published in 2004, it contains a list of 138 pages of contact information and most importantly, what types of special collections they hold. The headings for each library and archive is listed as: facilities, subject coverage, special collections, and publications.
An example of the coverage:
Cumbria Archive Service - Whitehaven
Special collections: Registers of ships and crew lists, etc. Whitehaven and Workington, 1786-20th century. Whitehaven Town and Harbour Trustees records, 1812-1894. Whitehaven Harbour Commissioners, 1924-1956. (registers of cargo vessels)
The Cumbria Archive Service covers: Barrow-in-Furness, Carlisle and Whitehaven.
The title is:
Maritime Information : a guide to libraries and sources of information in the United Kingdom. by Fenton, Briody and Macdonald. 2004. 1901703452
Maritime Libraries in the UK :
Aberdeen, Cumbria, East India Company, Liverpool, Shipwrecks, Wales