Shiver my timbers

"Shiver me timbers" (or "shiver my timbers" in Standard English) is an exclamation in the form of a mock oath usually attributed to the speech of pirates in works of fiction. It is employed as a literary device by authors to express shock, surprise, or annoyance. The phrase is based on real nautical slang and is a reference to the timbers, which are the wooden support frames of a sailing ship. In heavy seas, ships would be lifted up and pounded down so hard as to "shiver" the timbers, startling the sailors. Such an exclamation was meant to convey a feeling of fear and awe, similar to, "Well, blow me down!", or, "May God strike me alive and well". Since on the high seas the ship was the sailors' 'world', it may also be interpreted as an exclamation for "shake my world" as the subject being referred to could be, or may be considered a potentially 'world shaking' event.
Although the Oxford English Dictionary says the expression "shiver my timbers" probably first appeared in a published work by Frederick Marryat called Jacob Faithful (1835), the phrase actually appeared in print as early as 1795, in a serial publication called "Tomahawk, or Censor General", which gives an "extract of a new MS tragedy called 'Opposition'." In the words of the "old sailor":
The phrase appears in a news article showing that the phrase was in use at the time.
The Argus Newspaper Archive records the use in the news event as: "As for nine French men-of-war are laying along side us jist now, and overhauling our rigging and tactics, splinter my timbers into shivers if I don't think they are all buccaneers..." would indicate the meaning of "shivers" as the breaking into wedges, small pieces or slivers. Alternatively the word "slivers" itself (meaning a small, thin, narrow piece of something cut or split off a larger piece, which also defines a "splinter"), may be the word "shivers" expresses. The exact phrase is used earlier on the same page "Here's a breeze in a bumboat! shiver my timbers and top-lights, what will our Majesty's loblolly-boys say...". While the exact meaning may be different, the use was still that of an exclamation.
The expression is a derivative of actual 18th century nautical slang, when the phrase "timbers!" or "my timbers!" meant an exclamation (cf. "my goodness!") as can be seen in Poor Jack, a song from 1789 by Charles Dibdin.
The opening of the phrase, 'shiver my..', also predates Jacob Faithful with the following lines from John O'Keeffe's 1791 comic play Wild Oats an earlier example:
"Shiver my timbers" was most famously popularized by the archetypal pirate Long John Silver in Robert Louis Stevenson's Treasure Island (1883). Silver used the phrase seven times, as well as variations such as "shiver my sides", "shiver my soul" and "shake up your timbers". Another pirate, Israel Hands, also uses the phrase at one point.
Marryat and Stevenson both wrote Victorian fiction using standard grammar, even when their characters were pirates. The use of "me" instead of "my", which is common to many British regional accents, has appeared in popular culture such as with Popeye; one of his earliest cartoons from 1934 is entitled Shiver Me Timbers! The phrase was also commonly used in Arthur Ransome's Swallows and Amazons books, where it was said at least once in almost every book, most commonly by "Amazon Pirate" Nancy Blackett.