 The Berkshire No. 7 has historical importance because of its design , which reflects the construction of 19th @-@ century canal boats . However , there is no record that the barge was ever used on a canal . The barge is one of two surviving wooden @-@ hulled canal boats in existence . It was added to the National Register of Historic Places on December 21 , 1978 . Its nomination and listing is unusual because the Berkshire No. 7 was not yet 50 years old at the time of its nomination , and it sank in 1974 . It and the other two barges that sank with it are the only shipwrecks in Connecticut listed on the National Register of Historic Places . 
