True vs. magnetic north and a sailing invitation

True north is where Santa lives

Matthew Alice: I’m planning a sailing trip around the world. You’re invited! What is the difference between true north and magnetic north? Do the north and south poles really change polarity? What is dead reckoning? Welcome aboard, Matt! — Captain Mike, O.B.

We scraped up a quorum of the Bored of Grovelers here at the Della and PeeWee Reese Get-a-Clue Foundation. After some yelling and a big food fight, we voted to encourage more of this kind of mail. Letters (faxes, e-mail okay, too) with sincere tokens of appreciation. We offer these suggestions to prime the gift-giving pump and make your holiday shopping easier — free ducats to the international championship Jell-0 wrestle-offs (or equivalent); negotiable securities, large-denomination bills, and/or tasteful gems; anything advertised on TV after 1:00 a.m.; Italian shoes; homemade fudge. Nothing will catch our question-answering eye faster than your query taped to a couple of pounds of pistachio nuts or a Lexus. And remember, people aren’t greedy just at Christmas time; they need free valuable stuff every day of the year. So keep on giving. Like I always say, “Give a man a fish, he’ll eat for a night. Teach a man to fish, he’ll die of all that pollution in the bay, so you’d better keep giving him fish if you don’t want that on your conscience.”

Once we’d cleaned the mu shu pork off the recording secretary, the board’s second vote was to decline Cap’n Mike’s offer. We’ll go no farther than the edge of our cel phone range with any seafarer asking questions like this. Despite our reputation, we’re no fools.

True north is where Santa lives, the point at the northern end of the earth’s geographical axis where it pops out of the pack ice in the middle of the Arctic Ocean. Magnetic north is the nearby spot where the earth’s magnetic field is most intense (vertical). This is the “N” that most compasses point at. For various geologic and astronomical reasons, the true and magnetic north poles are not the same; and the magnetic poles do drift around over very long periods of time. At the moment, magnetic north is near Bathurst Island, Northwest Territories, Canada, about 1000 miles from true north and a good cup of coffee. Somewhere on your charts is a conversion table that will help you calculate true north from the reading on your magnetic compass. Please do this or you’ll hit something. An island, maybe.

No surprise, the whole routine is repeated in the Southern Hemisphere. The magnetic south pole is near the Adelie Coast of Antarctica, about 1600 miles from the geographic South Pole. Don’t know who lives there. Maybe the Great Penguin.

As for “dead reckoning,” it’s a fancy term for, “Urn, we used to be over there, and we sailed kinda this direction for, oh, a pretty long time it seems like, so I think we’re sorta around here somewhere.” It’s calculating your position by inference and guesswork, not by the stars or other location aids. Once ashore, dead reckoning is how a real man navigates because he doesn’t want to look at a map or ask for directions. But our board members also suggest it could mean, heck, we reckon we’d end up dead if we sail around the world with a guy who doesn’t know which end is truly up. Thanks anyway for the in-vite. Bon voyage.

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