Built in 1882, the Denny Tank was erected by the William Denny and Brothers shipyard to test ship hull designs and other innovations in marine engineering using scale models. Retaining many of its original features, including a water-filled tank as long as a football pitch, it is located in Castle Street, Dumbarton.
Today, Denny's shipyard, which built ships from clippers to the Canberra, is now gone. However, the Denny Ship Model Experiment Tank is still in use by marine engineers, but now forms an outstation of the Scottish Maritime Museum, based in Irvine.