Chigley (1969)

Season 1: Episode 10

At Treddle's Wharf, Mr Rumpling is supposed to unload a crate from his boat for Lord Belborough, and pick up a crate of scrap metal from Farmer Bell. While lifting a crate the crane fails and drops what they think is Lord Belborough's crate of valuable antique books into the canal. The solider boys are called and Private Armitage (the best swimmer) dives into the canal to rescue the crate. However due to a previous mix-up, the dropped crate is found to contain Farmer Bell's scrap metal, which obviously isn't damaged by having been dropped in the canal.