Ted Turner, 40, winner of the America's Cup, was driving his station wagon through the early morning heat toward his first small-boat regatta in years. His young son, Rhett, and wife, Janie, dozed in the back seat. The car was littered with lifejackets, scraps of line and other paraphernalia of the one-design weekend warrior.

Turner, however, is slightly out of place among weekend warriors. When it comes to sailboat racing - or starting a fourth television network or boosting his Atlanta Braves, Hawks or anything else - he thinks more like the Strategic Air Command.

Summer began for Turner with victory in the Annapolis-to-Newport race. His ocean racer Tenacious is in mid-ocean, making the passage to England for Cowes Week next month. By late August he will be in Seattle, racing for the 6-meter world championship. Next spring he will again board Courageous for the six-month battle to defend the America's Cup.

Thoughts of these great battles to come passed through Turner's mind as he drove toward a low-key, fun-only regatta on the Yango River here, 40 miles from the site of his 5,200-acre plantation retreat.

He was entered in the Hobie 18 class at the annual Hobcaw Regatta at nearby Mount Pleasant, and he had never raced a Hobie cat before. Rhett was overjoyed at the prospect of crewing for his father, so Turner was giving up a precious free weekend to sail with his son. There was only one thing that bothered him.

"I hope nobody knows I'm doing this. It's just supposed to be fun, right? I only went sailing on this boat once in my entire life."

Turner arrived at the Hobcaw Yacht Club at 9 a.m. By 9:30 he had seen the Charleston paper, and the story and picture headlined: TED TURNER MAY RACE.

He had also met the local Hobie cat champion, who just happened to be sailing the 18-foot class that day. By 10 a.m. a reporter had appeared to observe Turner's every move in preparing his boat.

"Hey, what are you watching me for?" Turner yelled. "I don't even know what I'm doing." By 11 o'clock a television crew was on hand, too. And the wind was up.

"What's your goal in this race?" the reporter asked.

"My goal?" came the caustic reply. "I'd say my goal was not to be humiliated, that's what my goal is."

That terse observation rendered, Turner sailed to the starting line more than an hour early. A committee member helped explain his mood: "We only had two boats in the Hobie 18 class until people heard that Turner was going to race. Now we've got five. I guess everybody wants a crack at Terrible Ted."

There were 18 classes lined up to start at five-minute intervals. In the melee of the starting gun, Turner became confused and missed his start. He went over the line nearly a minute after the local champ. When the race was over an hour later, Turner finished second - 1,000 yards behind.

Back at the dock, Turner had given up playing it cool. His first experience at racing a fast catamaran had changed his mood. He made a straight line for the winning boat, inspecting it for tuning tips, asking questions about technique from anyone who would listen - and who wouldn't listen to Ted Turner?

"I'mm telling you this is a terrific boat," Turner was shouting from under his engineer's cap. "Boy, I made a couple of mistakes - I made a million mistakes - but I never even sailed this boat but once before and . . . hey, did you see us out there? We were going like stink huh?"

Turner was close to the leader at the start of the second race Saturday, and the wind had picked up to 15 knots. This time, Turner cut his million misstakes to 500,000, and though he finished second again, he was much closer.

He crossed the finish line at 15 knots, flying a hull he and Rhett arranged on their twin trapeze wires.The leeward hull was throwing a rooster tail for all to see.

"Wow!" Turner shouted as he hit the beach. "This is the mostt fun I've had in years. Why didn't they have these boats when I was growing up? And it's sure more fun than racing 12-meters, and all that other serious stuff."

After the race Turner went to his plantation, and sped around in his jeep for hours, checking alligator holes and counting deer before a dinner of roast wood duck. But he couldn't get the Hobie cat out of his mind.

"Rhett, you did good," he said to his son.

"Yes, sir, but I've got to learn the jib better," said the boy.

"And I'm learning it," Turner said suddenly in the sharp way he has of inadvertently revealing his thoughts of the past moment. "Maybe I'm not too old after all," he said. "We're going to do better this next race, you wait and see."

In the morning, the Turner team was back at the Hobcaw Yacht Club - early. Turner went directly to the boat that had beaten him twice.

"I noticed sometimes you had one board down, and only one rudder down, and sometimes you didn't bother with the current when the wind was up, right? And look - your rig is much tigter than mine. Supposed to be tight, huh? And everybody is sanding their rudders before each race, that's what you do, isn't it, that's part of the game, right?"

"Yeah," the young skipper replied, semi-amazed at Turner's outright interest, but trying to keep his psycchological advantage, too. In his hand he had a piece of wet sanding paper.

"You better give me half of your sandpaper," Turner said.

"Sure," the younger man said, his psyche collapsing. Mad activity at the Turner boat: shrouds being tightened, rudders sanded, boom vane adjusted, extra weight removed. Again, Turner and his son were first to the starting area - an extra hour to practice, an extra chance to learn.

This time, when the gun sounded, it was Turner who crossed the line first. The winners the day before, caught in a hole in the wind, fell further and further back. As the fleet disappeared around the bend, Turner had a 300-yard lead.

But as the boats battled up the far shore, Turner's lead had been cut to a few feet. Now the other boats pulled ahead, accelerating as only catamarans can. Then Turner in the lead again, only to lose it.

"Here come the first boats in the Hobie 188 class," the loudspeaker announced, as 300 spectators moved toward the beach and the finist line. "Ted Turner is battling for the lead."

Indeed, as the line approached, Turner caught a puff and drove over the other boat, passing her to windward. But both cats were well upwind of the line, and had to turn directly downwind to finish. When they did, Turner's rival was closer to the line, and it seemed that way by strategy, not accident.

Thirty Sunfish were trying to start a race at that moment, and Turner and the other boat plunged into them and screamed one after another past the committee boat.

With Turner second again - but only by 50 yards.

On the docks there was tenseness. One experienced hand led his children away, saying, "Better get out of here. Ted's gonna be mad as hell."

Turner and Rhett pulled the Hobie onto their trailer without saying much. A small crowd gathered.

"Hey!" he shouted suddenly in his megaphone voice."You see us out there? That's the most fun I ever had in my whole life on any sailboat and I've been on a lot of sailboats."

"There's another regatta in two weeks, Ted," somebody called out. "You coming back?"

"Are you kidding?" replied the America's Cup skipper who had met defeat on the mighty Yango River. "You bet your butt I'm coming back." CAPTION: Picture, Ted Turner and his son Rhett learn the art of sailing a catamaran at Charleston, S.C. AP