This place really was a torpedo factory for WWII. I read a novel recently, written in the early 70s, and the protagonist had an office in the building. Now it is dedicated to art and is an absolute must to visit. Best way to get there is to take a Potomac tour boat one way from Georgetown. It will drop you off right in front of the Torpedo Factory in Old Town. Spend an hour or more there, then you can wander up the main street until you're ready to take a trolley (free, just hop on) to the Metro.