through the wind. The skipper and crew then roll the boat back to an even keel following the completion of the tack, allowing the sails to immediately resume their optimum shape on the new tack. The form of the boat in the water, not the rudder, is the primary mechanism for changing course from one tack to the other. Some keel boats may also be roll tacked. See also Glossary of nautical terms Racing Rules of Sailing References Sailing manoeuvres