Hi,
although it's mostly sailing ships, there are a couple of plans from the missing era in this link.. not sure how useful they'd be though
http://www.finemodelships.com/ship-plans/plans-Atlas-du-Genie-Maritime.htm
If Russain ships are of any interest, there are some free plans of Tsesarevich and Navarin available to download from a russian site
http://www.navarin.ru/page_info.php/pages_id/1
and there are paper models that could be used, such as
http://www.gremirmodels.com/ships.htm
For those interested in Tsushima, I'd recommend "Witnesses of Tsushima" by Westwood as it gives an account of the battle from several eyewitnesses' perspectives. It's one of those books that seems to have shot up in price for some reason, a pity..