Summer and fall are surly seasons for whitewater canoeists, who either sit home and sulk or go off and batter their boats and shins on low, slow rivers with rocks where the rapids used to be.

There is no need for such foly. Within easy driving distance of Wasington lies a body of water that is always deep and white with never a rock in sight. Columbus called it the Great River Sea; we know it as the Atlantic Ocean.

Canoe surfing is nothing like so difficult as it looks. The canoe is, after all, an ocean boat; the basic design was independently developed thousands of years ago by blue-water paddlers all over the world.

For a canoeist of moderate skill, in decent weather, canoe surfing is nearly as safe as surfbathing. "Moderate skill" might be defined as the ability to make it more often than not through mild Class III river rapids such as Yellow Falls on the Potomac, Bull Falls on the Shenandoah or Kelly's Ford on the Shenandoah.

It is also necessary to know how to turn a canoe upside down to empty it and to be nimble enough to slither aboard between waves, but anyone lacking these basic skills should stick to flat water anyway.

The dense salt water makes a canoe stable and responsive, and the only penalty for a mistake is a dunking. If the canoe overturns, simply haul it out beyond the breaker line, flip it over and try again.

Even a moderate ocean swell looks wild to a river runner, but the waves are oddly easy to handle. The difference is that the water is "standing" waves on a river is moving; in the ocean the waves move but the water only rises and falls. The ocean canoeist soon realized that the waves are harmless even if taken sideways, because the canoe rises to them like a cork. From the beach it looks spectacular, and before long the newcomer will be standing up to show off.

Riding a breaker is a different matter. It takes judicious paddling to keep a canoe from sliding off the crestand slewing sideways.When that happens the ocean comes aboard and the paddler abandons ship.

This is the danger point, if there is one, because it is possible to get conked on the head by the boat. This should not happen if one rolls off into the water head-first, so that the impact, if any, is taken on the back of the life vest that the federal law and common sense require every canoeist to have. lI have been dumped dozens of times without ever being punished by the boat, but wearing a whitewater helmet would be a good idea.

Even full of water a canoe is easy pull offshore end-on through the breakers (trying to empty the boat on the beach or in the surf puts a needless strain on the craft and the paddler). If the waves threaten to yank it away, turn it over and they will slide smoothly over the hull. If the water is so rough the boat cannot be handled without heroics, it's too rough for canoe surfing and probably for surfbathing.

Solo paddling is best because a light boat is more nimble and a canoe rides the surf best if it's stern-heavy. Kneeling is necessary, and thigh straps are a big help.

The ideal canoe for the surf is one with an ABS-vinyl hull and wood or plastic gunwales. Nonmetal gunwales are softer and more rounded and less likely to inflict bruises. Any of the half-dozen vinyl restoring compounds should be applied to the hull and gunwales to protect against sand-scour, but make sure none spills inside the boat, because it will make the interior so slippery the paddler will be helpless as a hog on ice.

Aluminum canoes tend to have sharp edges but are otherwise okay, except that they must be rinsed thoroughly after exposure to salt water (and there still probably will be some corrosive salt trapped in the seams and flotation chambers).

Sand will dull the gloss of a fiberglass hull, and salt water will destroy a wood or wood-and-canvas canoe.

A keeled boat will hold a line better, particularly in a stiff wind, but a wide, flat whitewater hull is more maneuverable and stable, so it's a standoff. w

Canoe surfing not only fills in the slow season for whitewater nuts, it can be ego-gratifying, especially if you are a person no longer young who never was able to get the hang of surfboarding. Bronzed, flatbellied young surfers keep coming up to you on the beach asking how you ever got up the nerve to try such a crazy thing.