To beat any one with a stick, or rope's end: perhaps a contraction of DRY RUB. It is also used to signify a good beating with any instrument.
·noun A blow with a cudgel; a thump. II. Drub ·vt To beat with a stick; to <<Thrash>>; to <<Cudgel>...
Webster's Dictionary of the English Language
To beat. (Captain's despatch.) "We have drubbed the enemy." ...
The Sailor's Word-Book