Round turn
From WikiPOBia
Specifically, a round turn is the passing of a line through 360 degrees around an object. The friction caused by the turn when such a line comes under tension is dramatic. Thus, in tending a line apt to come under heavy strain, a sailor will often "catch a turn" around a belaying pin, cleat, or bitt to aid him in maintaining control.
A common example is, "a round turn and two half-hitches", a knot said to be "Good enough for the King's yacht".
In the Canon
Characters throughout the canon frequently speak of being, "brought up with a round turn". For example, in The Reverse of the Medal, Wilks, a sailor on the HMS Irresistible says of Aubrey, "The black parson will bring him up with a round turn".[1]
Maturin often mistakes the phrase. At one point, he tells Major Beck that he "brought him up with a round stern". At another he assures Aubrey that, "if the Admiral proves inquisitive, I may toss him off with a round turn."[2] The nautical error, leaving aside the question of pun, is that a round turn helps to make something fast, not to let it loose.
