$10 for an adult ticket is money well spent. Unlike some museums, the Cod is very hands on - we were able to maneuver the huge deck gun as a two man team to take aim at passing boats in the harbor. They offer a full tour of the inside of the 300 or so foot sub that 90-100 (!!!) sailors once called home for months on end during World War Two.
The tour guide was knowledgable and happy to answer questions. Overall, it was a very informative experience and fascinating to see how a hopefully non-claustraphobic submariner lived and fought during WW2.