There is something about a mountain lake that draws boaters like a magnet. Perhaps it is a half-forgotten memory of childhood ... summer camp and waterskiing behind a mahogany runabout whose deck was as sun-warmed as the spray was cool. Or perhaps it's the crisp air and the contrast of the deep blue waters and the lush green forested hillsides.

For those of us who do our boating on coastal waterways or inland rivers, mountain lakes are a pleasant diversion from familiar surroundings, but plan your trip carefully. A little common sense and some basic preparations are enough to insure that your mile-high boating will be trouble free and delightful.

There are four areas that need to be prepared, starting with your boat, of course, as well as your tow car, trailer and, surprise, surprise, you!

As with any cruise, you'll want to check over your boat to make sure that everything is in good shape. Now would be a good time for that oil change and minor tune-up, a check of the various belts to make sure they're uncracked and, depending on your energy, a good waxing of the hull which will make road grime and bugs rinse off easily when you arrive.

High altitude on a mountain lake means thin air, and you'll want to check with your mechanic about tuning the engine to run with sea level power even in the mountains. Every engine is different, and some modern engines have sensors that automatically adjust the fuel mixture to match varying air densities, but you may want to rejet the carb or tinker with the idle stop on older engines. If time is not a problem, one solution is to get a quick carb adjustment when you get to your destination lake.

Your car will also have added strains put on it, not just from the thin air that reduces your usable towing power, but from the rigors of towing uphill on twisting roads. Heat is the number one enemy of your tow car, as you know from watching as your radiator boiled over after towing up a 10-degree incline in 90-degree summer heat.

Your first step is to upgrade your cooling system, which means a larger radiator (filled with the proper mix of fresh coolant!), a fan with extra blades, or even an electric auxiliary fan you control from the dash. You'll want to monitor your engine health, and "idiot lights" don't warn you of problems until after the damage is done, so install a set of gauges for water temperature, oil pressure, and perhaps transmission temperature.

Speaking of transmissions, heat can literally fry your trans fluid and destroy your tranny, so you might want to invest in a transmission cooler, which is simply a small radiator to keep your gearbox cool.

Treat your car to a tune-up and lube job, and check the ignition system in particular. While aftermarket "hot" ignitions are available, a stock ignition with new plug wires, properly set distributor with clean points, and spark plugs in the correct heat range will perform just as well for your needs. Last, you'll want to have secure stopping power coming down the mountain, so have your brakes checked, too.

Your trailer is just as important, so get the bearings repacked, check the tires for signs of misalignment or damage (and proper pressure), and test the running lights, too. With the boat on the trailer, make sure that all the pads and rollers are supporting the boat evenly without deforming the hull and, assuming that you have the correct hitch package, check the tongue weight to make sure it doesn't exceed the marked limits. By the way, you can reduce your towing effort by emptying the fuel and water tanks on the boat.

Once boat, trailer and car are in shape, it's time to take a look at yourself. The thin air at high altitudes (as low as 5,000 feet) can seriously affect your breathing and subsequently your heart rate. That easy hour of waterskiing at sea level can leave you limp as a dishrag on a mountain lake, and a hike up a nearby hill can finish you for the day. Take it easy until your body adjusts to less oxygen, and you'll soon be back at peak performance. By the same token, those mountain lake waters, so inviting on a hot afternoon, are probably a lot colder than you're used to, and that can dangerously sap your energy. Even at midsummer, deep mountain lakes can maintain a temperature that is well into the hypothermia danger zone, especially if they're snow fed.

While towing to or from the mountains, it's easy to try to cover too much ground. Cranking your rig around winding roads is both physically and mentally tiring, so you should plan regular stops to rest both car and driver. Besides, you'll probably be traveling slower than your normal highway speeds, so you'll need to allow for additional time.

Prepare thoughtfully, drive carefully, and don't forget to smell the pine trees ... there's nothing like a mountain lake for summer boating pleasure!