Gerry Spiess had his first day off in six months Sunday. He's been kind of busy, sailing solo 7,800 miles across the Pacific Ocean in a 10-foot sailboat.

Spiess, an ex-schoolteacher, left California June 1 with the goal of sailing to Sydney, in his homemade plywood sloop, Yankee Girl, which is 35.3 inches shorter than a Volkswagen Rabbit.

Spiess planned to arrive Nov. 1 after five months at sea, but wound up getting in a day early, on Oct. 31. Later he figured out that it actually was five months to the day.

"See, if I'd got there Nov. 1, like I planned, the arrival day would have been an extra day. So it actually would have been five months and a day," he said by phone from his home in White Bear Lake, Minn.

Spiess is very proud of his achievement, and proudest of all that he did it exactly according to plan, with no gear breakdowns, no unscheduled stopovers and no surprises. His master plan had him stopping at five islands along the way. He made every one on schedule, and his only regret is that his tyrannical schedule forced him to leave each island before he had a chance to explore its charms fully.

Now that he has a little time on his hands, he keeps falling asleep.

"I never got more than an hour of sleep at a time on the trip," he said. "I learned to take a snooze whenever I needed one. Now (wife) Sally has to drive the car when we go anywhere because I keep dozing off. And when I go to autograph sessions for my book, I'll be bending over to sign and I start falling asleep."

The book, fresh on the stands this month, is "Alone Against the Atlantic" (Control Data Press, Minneapolis, $12.95), the saga of his two-month crossing from Virginia Beach to Falmouth, England, in 1978. It was that hair-raising passage that convinced him a Pacific crossing was feasible.

And the Pacific crossing convinced him that any more efforts of this sort would be pointless. Spiess is hanging up his single-handing status. He made up his mind on the first leg, somewhere between Long Beach and Honolulu.

The first 10 days of that 34-day crossing were against contrary north winds of up to 30 and 40 knots in seas up to 20 feet. Though waves were not breaking over the boat, as they had at times in the Atlantic, Spiess still shipped water in the tiny cabin several times, and among other discomforts had to throw his sleeping bag overboard when it became waterlogged.

He decided on arrival at Honolulu never to make another single-handed passage on grounds it was "too difficult, too miserable and too dangerous. It's living too close to the edge, as I see it. I said, 'I'll finish this, but that's the end of it.' I've learned as much as I can, and the boat is as developed as she will be."

From Hawaii, Spiess went 1,150 miles in 18 days to tiny Fanning Island, a 10-mile-long dot in the sea. His navigation, by $20 sextant and compass, was perfect despite strong currents. He burned 40 gallons of fuel in his 4 1/2-horse outboard crossing the doldrums.

From Fanning it was another 17 days and 1,200 miles to Pago Pago, American Samoa, fighting 30-knot head winds part of the way. After a four-day layover, he pressed on for Fiji, a 730-mile passage completed in nine days. "Can you imagine that?" Spiess asked. "A 10-foot sailboat averaging 80 miles a day? It's unbelievable."

Fiji to Noumea, New Caledonia, was another 730-mile sleigh ride completed in nine days. "I came in Sunday and left Thursday, which was awful because it was a beautiful place and the people were wonderful," Spiess said. "But I had to push on. I wasn't cruising, I was making a crossing."

But after four months of warily watching every shackle and pin for wear and scanning the sky and sea for storms or rogue waves, Spiess found himself growing bold. The entry to Noumea is a treacherous channel through a reef. He barged in in the middle of the night, appalling the skippers in harbor.

Said Spiess: "I had to do something scary to get it out of my system. I was sick of being careful."

He called Sally and his parents from Noumea and told them to head for Sydney if they wanted to meet him. On the first day out, Yankee Girl knocked off 109 miles in 24 hours. Forty-eight hours later she lay hove-to in a two-day gale, buffeted by winds and imperiled at night by the worst electrical storms Spiess had ever seen.

He stayed in his tiny cabin, a familiar place, scrunched up with all the hatches locked and the sails down, the wind howling overhead, 1,000 miles from his destination waiting for relief. When it came, he went scudding into Sydney, covering an astonishing 260 miles his last two days.

Gerry Spiess is not the sort who'd stand out in a crowd. He wears conservative sport coats in earth tones and wire-rimmed glasses. He nibbles at his food and has perpetual trouble with stomach ulcers, except when he's at sea.

One night five years ago, he awoke before dawn and drew the plans for Yankee Girl. The next day he started building her from scrap wood. From humble origins in his Minnesota garage, she's been 11,100 miles across the most treacherous waters in the world. Spiess never has changed a thing from the original design.

After a round of TV appearances, boat-show talks and efforts to promote his book, Spiess plans to start work on a new project. He won't say what it is, except that it involves long-distance sailing, but not single-handing.

And what about Yankee Girl? She's back on a trailer in the garage, ready to be flown to California for Spiess' appearance Dec. 9 on the Tonight Show. Eventually she'll be donated to a museum. Spiess probably never will sail her again.

He has no remorse about that. "What I was trying to do was make a small boat that was a good sailboat. She's demonstrated her capabilities. You might be able to do what I did in a nine-footer, but nothing that size would perform like this."