As the new year approaches, so too does a vast armada of New Year's resolutions, their eager sails full of wind on the bright horizon. Sadly, most of these proud vessels will sink before the month of January has ended, taking with them their precious cargo of hope. The reason is that, like merchant ships preyed upon by pirates, they're unarmed.

Big mistake.

This year, give your resolutions some firepower. If you really want to change your life, you have to make it practically impossible to avoid doing so. And that in turn is another excuse for me to talk about one of my favorite topics: commitment devices.

What's a commitment device? Any technique you can use to bind yourself tomorrow to the wishes you happen to have today. The great orator Demosthenes, for example, forced himself into seclusion (the better to sharpen his rhetoric) by shaving half his head, making it too embarrassing to go anyplace. Victor Hugo, determined to stay in and write, had his valet take his clothes.

My nerdy hobby is collecting such tactics, and my new favorite is a service called Gym-Pact, which will let you specify how often you want to get to the gym -- and what penalty to impose on yourself (at least $5 a day) if you fall short. Starting in the new year, the company says, you can download a smartphone app that tells Gym-Pact when you've been to the gym. The company will rely on a database of more than 40,000 facilities in conjunction with the global positioning system.

You'd think merely joining an expensive health club would motivate exercise -- Freud himself said that fees are therapeutic, although of course he was biased -- but once this money is paid, it's too easy to mentally write it off. Gym-Pact strives to make each lapse costly.

Exercise isn't the only subject of New Year's resolutions. But you can raise the cost of breaking almost any resolution via, which will charge you for practically any failing you choose.

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If you prefer to give your resolutions sharper teeth without resorting to the Internet, by all means rely on family and friends. Telling everyone you know that you've decided to quit smoking, for instance, will mean embarrassment if you start puffing again, and that's not a bad deterrent. Better yet, tell yourself -- and everyone else -- that if you decide to light up, you'll only do so using a $20 bill. Surely the sight of Andrew Jackson going up in flames will discourage you. The danger (aside from self-immolation) is that you'll come to see this as a tolerable cost, and keep right on smoking.

Local charities ought to offer commitment devices as a way of raising money. Imagine if your local Elks lodge or PTA held a gala public weigh-in every New Year's Day. If you gained weight from one year to the next, you could pay whatever you'd pledged per pound.

Commitment devices rely on penalties and rewards, the stronger the better -- which makes it puzzling that sex is so infrequently used in this way, at least as far as I know. Marital therapists, hold your fire; I'm not suggesting people grant or withhold it to get what they want, although that's certainly a time-honored tactic. Think of the ancient comedy "Lysistrata," in which the women of Greece banded together to withhold sex until the men ended the Peloponnesian War.

I'm simply suggesting that a person writing a book might authorize a significant other to veto sex on any day two pages or more weren't produced. The sedentary could commit to the same on any day the pedometer didn't show an extra three miles.

You get the picture. I leave it to readers to imagine subtler ways of using this approach for self-improvement. If nothing else, it'll take your mind off whatever you plan on giving up in the new year.

Daniel Akst is a member of the Newsday editorial board.