Sailors shorten them to up or down as indication of both direction and boat heading. You will turn the boat up-towards the wind-or down-away from the wind, which implies of course awareness of the answer to that question. Where is the wind? Say you are sailing with the wind blowing over the starboard side on a beam reach. To takeher up requires a right-hand, or starboard, turn onto a close reach, and the sails would need to be trimmed (pulled in) to the new point of sail. If you take her farther up onto a beat, you would be sailing on a starboard tack. She won't go up any higher. If you try to press her closer to the wind, she will slow down and the sails will begin to flutter, or luff, like flags. Of course the same principle applies with the wind blowing over the port beam. In that case, to take her up requires a left-hand, or port, turn through a close reach onto a port tack. In some cases, depending where you want to go in relation to where the wind meets the centerline of the boat, you will need to turn either the bow or the stern through the "eye" of the wind, the direcion from which the wind blows. Turning the stern through the eye of the the wind requires you to jibe.