The scope of this piece is not definitive but hopefully it will be somewhat helpful.
At the CMMG meeting on Tuesday, February 5, 2013 the question came up of where to find plans for a specific ship or class of ship. In this case the specific class of ship was the Canadian Pacific Empress class ships.
Well that was daunting but those who were at the meeting were determined to be helpful. So we asked questions. Where was the ship built? That's a good place to start. In this case the ship was built in the United Kingdom. With some further discussion the best suggestion that could be made was that the national archives in the United Kingdom should be consulted.
Generally speaking, the national archives of the country where a ship was built, is often the place where ships' plans eventually get stored. So it's a good starting point to search for plans. If any particular ship of interest has been involved in a war and captured then it's a good bet that the country that captured it documented it as fully as possible and their archives would be worth checking.
Most countries that have archives have web sites dedicated to them. Here are three with links to their home pages.
Library and Archives Canada
The National Archives
for the United Kingdom
for the United States of America
Other archives can be found by searching with Google.
Keep in mind that should you find that the plans you seek are indeed stored in archives that getting copies of them may be expensive. Most archive facilities will have the means to make copies but doing so could be costly as can shipping.
Most archives have either catalogued their collections on line or are in the process of doing that. Digitizing the items in storage is another matter.
When you are looking for something in the way of plans or other information on a ship, be prepared to spend some time and work on getting what you want and be prepared to be disappointed. Good luck with your efforts and may you be rewarded for your efforts.
War of 1812 Plaques - On Iroquois Island in Iroquois, Ontario in a park overlooking the Iroquois lock stands a memorial with four plaques detailing aspects of the War of 1812. ...