### Clue: At sea, couple with rum to drink, when spliced (9)
### Answer: MAINBRACE 
 ### Explanation: Definition: rum to drink, when spliced
 MAIN(the seas, poetically) **plus**(At …) BRACE(a couple;a pair of something, typically birds or mammals killed in hunting).
Cryptic defn: Reference to the naval order "Splice the mainbrace" ie. to issue the crew with an alcoholic drink, most likely, rum.