In running nearly before the wind, when a vessel runs off her helm so much as to bring the wind on the opposite quarter to which the boom is; a very dangerous proceeding, as if there be no boom guy a sudden gybe, or a gybe "all standing," may be the result. For safety, the helm should be put down the instant a vessel begins to run off. In match sailing, in running for a mark, yachts are often brought by the lee through a shift of wind, and frequently they are kept so, if a spinnaker or squaresail be set, and if near the mark, to save a gybe, every precaution being of course taken to prevent the main boom coming over, by hauling on the guy or pressing against the boom; this risk, however, should only be hazarded in very light winds.