headrail

noun

1. The supporting rail of a blind (such as a Venetian blind) that encloses its mechanism; a headbox.
2. A railing, on a sailing ship, behind the figurehead.
3. (in-plural, obsolete, slang)A person's tooth.

   “Initially, our man was the favourite, the boat's crew cheering him on as usual: 'Now my boy! Knock out his head rails' . . .”