Pete Sheehan doesn't look like a professional athlete.

He wears scuzzy old clothes when he goes to work and he never gets enough sleep. He drinks cheap gin at night and has to share his little cottage with two other guys who wear grimy cut-offs, too.

When the beer-drinking steelworkers come down from Pittsburgh, Sheehan's job is to convince them that they are the athletes and he is just the hired help.

"When we get a marlin working the baits my job is to hook him. Once he's hooked I hand the rod to the angler and then I stand behind him. I have to tell the captain where the fish is so he can handle the boat, and I have to tell the angler what to do with the fish.

"Sometimes the angler won't do what I tell him. Then I get mad. I lean right over his shoulder and I tell him, "Look, buddy, this is a once-in-a-lifetime experience. You'll probably never see a fish like that again so you just better get into it because if you don't I'm gonna be one teed-off dude.""

Sheehan, who comes from Fairfax, Va., is a mate on the marlin fishing boat Capt'n squid. His two roommates, Mike Everly and Dave Johnson, also from Northern Virginia, mate for competing Hatteras boats. There is great satisfaction in watching professionals at work and all three of these young mates qualify.

They're strong, young, agile. They're quick of hand and eye and they love their work.

"People think we're down here for a summer job," Sheehan said last week. "They think we're working for the parties. Well, we are. But none of us would be here just for the money. We have one thing on our minds. Catching marlin."

Sheehan just finished his junior year at Virginia Commonwealth University where he is a drama major. He completed his last final exam on May 3, raced out of the classroom and drove immediately to Hatteras. The next morning he was on the dock at 6 a.m., ready to work for Capt. Ronald Stowe. He has been there every day at 6 since. This is his third season.

The marlin hunt is to the average recreational fishing trip what the Sunday office softball game is to the Yanks and the Red Sox on playoff day, 1978.

It is a high-stakes game played out on the big, brilliant blue waters of the Gulf Stream 15 to 40 miles offshore, where there is no place to hide.

It is no scene for the weak of heart, particularly not here off Diamond Shoals, 14 miles of shifting sand and turbulent seas where the north-flowing Gulf Stream meets cold currents coming south.

"They call it the graveyard," Sheehan said.

His average day lasts 14 hours, from 6 a.m. when he begins rigging the ballyhoo, mackerel and squid trolling baits to 7:30 or 8 at night, when salt is washed from the boat and he and Johnson and Everey are ensconced in their living room, digging rock music and tying up new steel leaders and lures for the next day's party. The pay - $35 a day plus tips.

The marlin haven't been thick this year and all the pros are waiting for the expected July blitz.

That is when the competition for top boat will reach a peak that continues through high season in September.

Top boat is the one with the most marlin. Does it really matter in terms of bookings?

"Not a bit," said Bull Tolson, a local who stopped by Sheehan's place for a beer. "It's just pride."

After the early dirty work is done the mate's job is to perch on the flying bridge behind the skipper, peering back at the six trolled bats and waiting for a fish to rise. Marlin often trail the boats before they strike, dancing on the surface from bait to bait, lit up and fired with feeding desire.

Their tall dorsal fins and long bills cut the water as they race with incredible speed, big fish intent on murdering what they think are little fish.

The mate leaps to the deck with a thud and sprints from rod to rod, teasing the game fish by drawing the baits away, then dropping them back. The marlin cuts the water, his bill stabbing at the fleeing bait.

"There's two turn-ons," said the lanky, rawboned Sheehan. "Hooking him and wiring him (bringing the fish to the boat hand-over-hand after the angler has fought him to the top of the 15-foot wire leader."

The mates get to do both, sometimes at their own peril.

Last month Sheehan hooked a big fish. He was sure it was a marlin. It fought fast and hard but finally it was whipped.

The leader was at the rod tip. Sheehan grabbed it and wound it to the boat by hand. When the fish was alongside he was shocked. It was a wahoo, a huge one - maybe 70 pounds.

"I never saw a wahoo like that. I called the fishermen over to show them. But when I looked down he was just lying there on his side next to the boat, whipped. The hook had come out.

"I wasn't going to lose that fish. I grabbed the six-foot gaff and hung over the side. I could barely reach. I sunk the gaff but I couldn't hand on. He drifted off with the gaff handle stuck out like a mast. He wasn't moving.

"I had to get him. I just rolled on in the Gulf Stream.

"When I hit the water I brushed against the gaff and grabbed it as I was going down. That did it. The fish took off with me hanging on. He was flying.

"I couldn't hold him. Off he went. Now I was 20 yards off the boat and the current was streaming. I grabbed a line off one of the trolling rods and one of the anglers reeled me in.

"Cap'n Ronald must have been on the radio that day, because when we came in they had a citation all made out for the guy who reeled me in - for a 185-pound hippie on 80-pound-test line."