Years ago when I had a leaky Lightning and the world was young, a sparkling December day lured me out for a last sail of the season.

Miss Fury was moored at Galesville on the West River. I paddled the dinghy out to the yacht, climbed aboard, stowed the canvas cover, dropped the centerboard and set sail for the Bay in the caress of a brisk following breeze.

I saw but one other boat that sparkling day, out near the mouth of the river. She was a sturdy cruising sloop of about 30 feet, also being singlehanded. Her skipper glanced over as we crossed tacks, and a look of horror crossed his brow.

I puzzled over that look for a decade before figuring it out.

The man thought I was nuts.

The man was right.

It's a sad truth that in these fast times few things are done properly. We don't stop to re-tune the car every time it misses; we don't patch our boots the minute they leak and the squeaky front door might wait a year for a squirt of 3-in-1.

We run few risks in our mundane lives, so what's the loss?

But when these slovenly attitudes carry over onto small boats on cold waters, the perils multiply.

So it was that a proper yachtsman was shocked to see a half-wit cross his bow in a 19-foot sieve, wearing no flotation and carrying no survival gear, grinning blithely as he pranced along a winter tightrope.

As luck had it, the rudder post didn't break that day, nor did the pencil-wide seam next to the centerboard trunk open into a geyser, nor did the tinder-dry mast snap. Had any of those things happened and deposited me in the frigid Bay, someone else might have had to write this.

But I am older now, and smarter in my way.

Three weeks ago I got around to making a purchase that should have been made 20 years ago: a neoprene wetsuit.

This marvel of 20th-century ingenuity makes a person all but immune to cold water, dramatically increases his personal flotation and generally is the kind of thing a fellow ought to have if he likes boats and the water all months of the year.

Wetsuits are much better suited to non- diving sports now than in days of old. Spurred by increased interest in kayaking and canoeing, manufacturers have come up with lighter, thinner and looser-fitting suits that provide the mobility for vigorous out- of-the-water activity.

I put together a combination of farmer- john (a pants-vest combination like a coverall) with an eighth-inch-thick paddling jacket and a pair of booties. In early March, thus protected, I tackled the Cacapon River in a leaky kayak and emerged eight hours later, dry as toast. It was warm, wonderful West Virginia.

But the multitude of uses this little outfit will serve is what's most appealing. It'll be a winter-sailing getup and an oyster-diving and snorkeling suit. I'll wear it aboard the skiff on cold days for duck hunting or winter fishing and stay warm as a duck. And of course it remains a must for cold-water canoeing and kayaking. In all boating circumstances it will be worn in conjunction with a flotation jacket.

A friend wears his under his clothes when he rides his motorcycle in the winter. It also makes an ideal costume for Halloween and a woman I know said it'll come in handy if I ever get kinky.

For $160, I don't know how I lasted so long without one.

The only other time I wore a wetsuit was for scuba diving and I was under a misimpression about how they worked. I thought water went through the rubber and then was trapped next to the skin, where it was warmed and stayed warm.

But in fact as long as you don't completely immerse yourself, water just rolls off a wetsuit. When you take a thorough dunking, it gets in through cracks and seams and is trapped and warmed.

What this means is that if you wear one and have only incidental contact with the water, you stay completely dry. What a pleasant surprise.

Wetsuits are available at most outdoor recreation suppliers and provide the cold- weather recreational boater with a wonderful ace in the hole. They take the worry out by assuring that a capsize is not necessarily a catastrophe.

What do you suppose they'll think of next??