IT is hereby decreed that the Columbus quincentennial year officially opens - at least for the purposes of this newspaper - with Columbus Day weekend Oct. 12-14 of this year.Many of us will find ourselves getting back into the subject of Columbus and his voyages in a way we haven't since school days, and early school days, at that. Columbus is a natural hero for children, who are, after all, little explorers themselves, setting off into the unknown every day of their young lives. But the reputation of the Genoese mariner has rather suffered in recent years, and it would be a shame, amid the controversy about "celebrating the discovery" versus "commemorating the encounter" to lose sight of the achievements of this splendid sailor. What a thing it was to make it across a great ocean in three little ships. He continually underestimated, almost willfully so, it seems, the distance of a degree of longitude, and so of the circumference of the earth and the distance from Spain to Japan. No wonder they doubted him at the courts. But if he had really known how far it was, would he have stayed home? That seems doubtful. Aside from the questions of a New World and the distance to Asia, we read of his adventures and can't help sailing along with him metaphorically. There are human activities so fundamental that they generate metaphor out of all proportion to the time they actually take up in most people's lives. The farm sector of the labor force, for instance, is small in developed nations, and yet the metaphors of sowing and reaping, seedtime and harvest, continue to resonate, even among those whose workdays could be described as spent pushing a cursor around a computer screen. Sailing is another one of those activities that are fundamental - elemental - even for those who don't pursue them. My own limited sailing experience - consisting of a few seasons on the Charles River in Boston several years ago, plus two or three other outings elsewhere - has given me a frame of reference that is with me almost daily. There is, for instance, a peculiar standard of vigilance required on a sailing vessel, for which there is no substitute. One remembers that the first major accident of Columbus's voyages was the Christmas Eve shipwreck of his flagship, when the officer of the watch took an unauthorized nap and left a sleepy cabin boy at the helm. The lad drifted off, everyone else aboard was asleep, and the Santa Maria slid silently onto a coral reef. At a humbler level, "taking on water," for instance, is the phrase that comes to mind on the days when the office in-box is filling up faster than it can be emptied. When a discussion needs someone to argue the other side so that the group can be sure of making the right decision, I have a mental image of a sailor jumping to the other side of a small boat so that the weight is balanced properly after tacking. And what about tacking, or taking a different tack? It's occasionally misspelled or mispronounced as "tact," which suggests some confusion with "tactics," though perhaps not undeservedly so. Nautical tacking is zigzagging, as one must do when sailing into the wind. Tacking is often tactical, in the case of actual as well as metaphorical sailing. If one's destination happens to be where the wind is coming from, the indirect approach may be called for. The beginning sailor may find having to maneuver this way disappointing but soon learns to appreciate the control one has in doing so, with the sail pulled in tight. By contrast, running, or sailing with the wind behind one, can be quite exhilarating; but a novice may be asking for trouble. This is how Columbus found, or rather made it to, the Bahamas. (His course was simple: sail to the Canary Islands, then turn right, excuse me, starboard, and head due west. Can't miss 'em.) But with the sail let out all the way, the novice has less control and is subject to an accidental jibe, with the wind catching the sail and flipping it around to the other side of the boat. The boom coming across can be dangerous, to say nothing of the indignity of the whole thing. It sounds rather like other parts of life, doesn't it?