Green’s Dictionary of Slang

let her rip! excl.1

also let her roll! let them rip!
[? f. steamboat engines that exploded or ripped when under excessive pressure. The phr., according to Ware, was common among their captains when urging the crew to put on full steam when racing against a rival boat; also as v.]

(orig. US) an excl. suggesting that someone should go full speed ahead, whether lit. or fig., to remove any impediment to progress.

Show quotations
[US]N.O. Picayune 31 Aug. 648/2: Why in the name of h—ll’s eternal flints don’t the engineer pitch in more pine knots and crack on more steam? Let her rip [DA].
[UK]T.H. Gladstone Englishman in Kansas 36: The General’s ‘Now, boys, let her rip!’ was answered by some of the shot missing the mark.
[UK]G.A. Sala My Diary in America II 246: Give her goss, and let her rip!
[US]W.H. Thomes Slaver’s Adventures 353: ‘Let her rip, sir?’ asked the mate, tearing off his hat and vest in his excitement.
[Scot]R.L. Stevenson Treasure Island 91: When the time comes, why let her rip!
[US]C.H. Hoyt A Trip to Chinatown Act II: This means two weeks more off my life — but let her rip!
[US]A.H. Lewis ‘Jess’ in Sandburrs 20: Let her roll! Come a-runnin’ and don’t pester none with ceremony.
[US]O. Johnson Varmint 277: This team’s just begun to play [...] Let her rip!
[UK]Marvel 8 May 6: ‘Let her rip, boy,’ he said. ‘Hit as hard as you like!’.
[Scot]Eve. Teleg. (Dundee) 24 Nov. 3/4: A nice girl behind him on a pillion [...] urges him to ‘let her rip’.
[US] (ref. to late 19C) N. Kimball Amer. Madam (1981) 329: Years of discipline shot to hell. I thought, let ’em rip.
[US]Z.N. Hurston Seraph on the Suwanee (1995) 771: ‘Ready for the question?’ ‘Let her rip!’.
[US]Southern & Hoffenberg Candy (1970) 153: Stripped for action, eh, Doc? Then let ’er rip!
B. Oakley A Wild Ass of a Man 33: Attaboy! [...] Let ’er rip man, let ’er go, go, go!
[US](con. 1916) G. Swarthout Tin Lizzie Troop (1978) 114: Tucker slammed the door, backed off, and waved an arm. ‘Let ’er rip!’.
[Aus]B. Humphries Traveller’s Tool 125: She tends to come on a bit strong with the philosophy. I let her rip.
[US]S. King Dolores Claiborne 75: I stood there [...] laughin from way down deep inside my belly, the way you do when you know you can’t do nothing but let her rip.
[NZ]McGill Reed Dict. of N.Z. Sl. [as cit. 1988].