I've come across a couple of interesting old books on Project Gutenberg that might of interest to several members here who are drawing older vessels.
The first is
Ocean Steamships by F. E. Chadwick, John H. Gould, J. D. J. Kelley, William H. Rideing and A. E. Seaton, published 1891.
It covers the construction and operation of ocean liners and has some interesting information on shipping routes and companies of the time. Has some very nice illustrations too.
https://www.gutenberg.org/ebooks/54136
The second is
The Fleets at War by Archibald Hurd, published 1914.
This is one of the series of 'Daily Telegraph War Books', it covers the main events of the early battles in 1914 and has a lengthy section on the ships, manpower and bases of the Royal Navy and German Navy. Many of the illustrations of the ship classes look like those from Janes but the photographs are of poor quality (probably not bad for time!). As a quick and useful guide to the fleets of 1914 and the lists of ships in classes etc., this is a handy reference.
https://www.gutenberg.org/ebooks/54275
The next is
Q-Ships and Their Story by Edward Keble, published 1922.
This is a pretty thorough account of Q-ship operations including maps and photographs.
https://www.gutenberg.org/ebooks/54338