If you happen to be on the US East Coast, there are scores of museums to see but here are few of the highlights:
Boston, MA Charlestown Navy Yard, USS Constitution, USS Cassin Young
http://www.nps.gov/bost/historyculture/cny.htmNew York, NY: USS Intrepid, USS Growler
http://www.intrepidmuseum.org/; American Merchant Marine Museum, Kings Point, NY
http://www.usmma.edu/about/Museum/default.htm Philadelphia, PA: USS Olympia, USS Becuna
http://www.phillyseaport.org/Baltimore, MD Baltimore & Chesapeake Steamboat Co.
http://www.steamtug.org/; Baltimore Museum of Industry
http://www.thebmi.org/ Newport News, VA: The Mariners' Museum / USS Monitor Center
http://www.mariner.org/Washington, DC: Too many to list separately but you'll want to start with the Smithsonian:
http://www.maritimemuseums.net/DC.htmlCharleston, SC USS Yorktown, USS Laffey, USS Clamagore, USCG Ingham
http://www.state.sc.us/patpt/Wilmington, NC USS North Carolina
http://www.battleshipnc.com/ Tampa, FL SS American Victory
http://www.americanvictory.org/Pensacola, FL US Naval Aviation Museum
http://www.navalaviationmuseum.org/Mobile, AL USS Alabama, USS Drum
http://www.ussalabama.comI've had the pleasure of visiting most of the above & would recommend Washington DC / Newport News as a great starting point. I have to admit I'm envious of you Brits with your available selection.
An excellent resource for any maritime buff that lists hundreds of museums throughout the US & around the world:
http://www.maritimemuseums.netChuck