The National Maritime Museum has put online its Admiralty collection of sailing warship plans, commonly known as the 'Sailing Navy collection'.  This means that 711 plans are available to look at online covering the period from 1700 to the 1900s. The collection can be viewed here.

You can browse through the entire collection or by maker or century if you wish to narrow it down.  Once you've found an image you like, you can enlarge it so that the detail on the plan can be clearly read and images can also be emailed to friends or ordered up as prints.