They finally broke up on the coral reefs of Tahiti, though friends say it could have happened anywhere along the way. In Miami or Montego Bay. In Panama or the Galapagos. Some partnerships, fragile as porcelain, somehow endure. Yet others, seemingly bonded hard by shared danger and high adventure, shatter almost overnight.

So it was two years ago when Bill Goodwin and Paul Woodard, both high-visibility Washington lawyers, took leave of jobs on the Hill to bend the sails on their 41-foot yawl, Felicity. Together, they would circumnavigate the globe. Vows were toasted to bursting champagne on a Annapolis dock, and , indeed, there was no reason to doubt it would be so.

They shared so much - North Carolina roots, stints on Sam Ervin's prestigious Judiciary subcommittee, a fast friendship. Together, they had tacked and come about on the Chesapeake, ventured in tandem to the Caribbean. As for The Trip, well, it had been two years in planning, and before shoving off they acknowledged the pluses while conceding the risks. Expectations were great, but certainly well-grounded.

So what if they were different men? Both knew it. Salt and pepper personalities would properly season the long, lonely stretched to be faced at sea. If the fortyish Woodard seemed overly cautious, a meticulous sailor with a taste for starched khaki, the younger Goodwin was an irrepressible roustabout in faded jeans, fun-loving and hang-loose.

Diversity would be their diversion, one man's strength shoring up the other's shortcomings. Or so they thought. Theirs was christened The Perfect Partnership, but the perfect partnership made it only one-fourth of the way.

Last year they parted, with Woodard paying a sum in settlement and sailing on. Goodwin hitched up with his girlfriend (whose presence Woodard simply would not abide) and stuck out the proverbial thumb. Felicity, with Woolard and a pickup crew, is reported under sail somewhere between Fiji and New Zealand.

Goodwin and company are said to be trekking a la Crusoe in the vicinity of the South Pacific, heading leisurely west. Word of their split drifted east some time ago, but mutual friends weren't too surprised. Well-rehearsed combinations often fail to react, though it may appear as if sodium and chloride suddenly refused to take salt.

IT'S NOT uncommon for partners to break up," says Woodard, via long-distance confessional from Suva City, Fiji. "Actually, it's rare for one to work out. Whole families break up at sea. A lot of changing goes on out there. Sometimes it clicks and sometimes it doesn't.

"Sometimes it was a hell of a lot of fun; other times it was not.

"But there was no way we could know in advance if we would get along for extended periods on a small boat. We recognized our differences. Bill is looser in approach to most things and I'm very conservative by nature . . . I've met a lot of skippers who lost their boats out of carelessness."

For California-launched sailboats heading around the world, Tahiti is frequently the first landfall, and Papeete International Airport is said to do a booming business among disillusioned shipmates seeking one-way tickets home. At times, Papeete harbor seems filled with floating couches that list badly from the gestalt of frustrated Magellans. Woodard, hardly unique thereabouts, tied up for a respite in Papeete after his final passage with Goodwin.

"I watched boats coming into the harbor with people on deck screaming at each other," he says. "Sailing partnerships are a chancy business. Bill and I recognized that we might break up, but we didn't make a provision for it in advance! If it were to happen, we figured we might have to sell the boat wherever we were. We didn't expect to (break up), but from knowing other partnerships, we knew it was a hell of a risky thing."

THERE ARE endless stories of partnerships' going the way of Davy Jones' locker - straight down.

Even the best friends have come to blows below deck. And there have been an odd sinking or two, like the California computer whiz fired up with romantic notions. He sold his home (over his wife's objections) to buy a boat, packed her up and set sail for Tahiti. It was a nauseous, green-faced crossing, and, alas, like other sea-sick explorers, he lost the faith and flew home. Alone, His wife refused to go back - she had fallen in love with the sea - and found a crew to carry her onward.

Or take the Washington writer who recently agreed to sail the Atlantic with his girlfriend; she would cook. Dreams of sunny days and steamy nights.

Only real life never rivaled the thrill of anticipation. She was High Vegetarian, and stocked the shelves simply; brown rice, boiled oats and such. Stomachs growled; they caught a few fish. Her cat didn't mind, though it mistook the cabin for a kitty-size kitty-litter box. (Where else was a cat to go?) The skipper was even less amused when the cook insisted on a twice-a-day shampoo and depleted the fresh water a few days out of Liverpool.

(Most failed partners asked to go nameless; they didn't want to unfurl their dirty sails in public.)

AS SOON AS Miami, Woodard and Goodwin realized life at close quarters was going to be tough. "Imagine if you had to live in a tiny efficiency apartment with someone and were not allowed to go outdoors for weeks on end," explains Anne Arcos, Woodard's ex-fiancee who got disengaged recently when Felicity's skipper decided to extend his voyage a year. "And every time you passed each other in the hall, you had to turn sideways to get by. You might come to feel like throwing your partner overboard, too."

"There were some tense moments," admits Woodard.

"Paul is a perfectonist and must have things done when they have to be done; Bill is very relaxed and gets to things when he gets to them," says Arcos.

Tension and monotony were broken somewhat by the hitchhikers picked up at one port and dropped in another. Still, Woodard was constantly frustrated by what he perceived as Goodwin's inaction; Goodwin felt hassled by Woodard's apparent overreaction. Woodard did not trust his partner at the helm. He couldn't relax; he couldn't sleep. Their chemistry clashed; their differences became liabilities.

"Each of our approaches grated on the other," says Woodard. "A boat is a small place."

"They just looked at the voyage differently," says Arcos."Paul saw it as a sailing adventure; Bill as a two-year vacation."

Finally, the separation from his girlfriend became too much, and Goodwin insisted she join Felicity in Tahiti. No dice, said Woodard, who bought his partner and sailed into the sunset for Bora Bora.

OF COURSE, not all partnerships are destined to sail over the edge, but seasoned sailors warned new salts to size up advantages against risks long before shoving off. "Sharing a sailboat is like sharing your lady," says John Bergreen, owner of Annapolis Yacht Sales and Service. "Boat owners get very attached to (and jealous over) their boats."

Money, of course, is one excellent reason to sail a deux . With the cost of some boats rivaling the cost of new homes, a joint venture can mean the difference between calling a boat (almost) your own and the lonely life of a landlubber. There are fees aplenty - slip rental, insurance, maintenance and yes, general chores. A modest slush fund can help.

And, advised Leo Batzer, past commodore of the Sailing Club of Washington, "All parties should be capable sailors and know the boat thoroughly."

An earnest neophyte with some bucks and a yearning to know the wind may find apprenticeship to a cash-short old salt a fine and proper marriage of convenience. But what happens to the old salt when the wee guppy grows big fins and wants to sail away on his own?

Or what to do if one partner feels content to simply float about the Bay, while the other presumes to be Columbus and, by Ferdinand, aims to sail the Atlantic? Best if partners on a common wind of interest and experience. Partners should want the same things.

Potential mates are advised to find out straight away whether they seek the ocean, the Bay or the river as their new tub. Is cruising or racing your bag? What happens if your Queeg discovers tennis?

Partners should prepare for every eventuality on paper.

Sailing partnerships are frequently shortlived, and contracts between sailors are not uncommon.

The most successful sailing partners highly recommend that such a document include a fair and equitable exit clause (buyout terms), a schedule for weekends and holidays, a division of duties (on land and sea) above and beyond digging deep, and a time limit - say three years, with an option to renew.

SUCCESS IS great glue for togetherness. And success is among the ingredients that bind banker Larry-Bullman and three partners together under sail on the Annapolis-based racing sloop, Yellow Jacket. The championship one-ton sloop has snapped up 40 racing trophies, including one for the impressive Annapolis-to-Newport win last year. The crew of businessmen has thrived for six years.

"It's unusual for a partnership to last that long," says mortgage banker Mike Winston, a former Yellow Jacket partner and self-described "morale officer" until he cashed in his chips this spring, receiving an undisclosed sum of cash and a note for a split he describes as "very compatible and amenable."

The temperaments aboard the racing sloop just seemed to mix well, say the shipmates, and, after all, their togetherness was in writing - a contract that provided a smooth transition.

There were other rules as well. They took turns as "skipper of the week." While no single ego was dominant, waterborne decisions were made in one bold stroke, rather than by committee. (Such are the demands of the sea.)

Most Yellow Jacket weekends were devoted to racing, with any free weekends preassigned. Everyone was allowed one guest.

Too much togetherness (and lack of money) was never a factor, as it is in many sailing partnerships. Nor was Tahiti a shared horizon. And their spouses/girlfriends seemed to like each other well enough.

But if partners are pondering four or more in a barrel, says Bullman, the "girls better get along or you're going to have problems." At sea, there's no walking away from a jerk.

Of course, a sailing couple should share the enthusiasm."Show me a guy's wife who doesn't sail and I'll show you an unhappy marriage," he says.

GOODWIN AND HIS girlfriend, Chris Moore of Washington, explored Tahiti and Moorea while the partners came to grudging terms. Bill and Chris, who could not be reached for comment, are now said to be traveling by plane. Their paths crossed in Bora Bora, Pago Pago and, in January, on Fiji.

Meantime, for Woodard and Felicity, it's New Hebrides or bust, followed by the Solomons, New Guinea and Bali (where he planned to dock for three months). Then it's on to New Zealand, Australia and back home perhaps next year.

There's a chance, however slim, that the partners may even hitch back up somewhere, says Woodard, who sends a regular status report to Goodwin via his partner's father in Eatonton, N.C. "We just might get back together."

Out there on the deep blue sea, pitching and groaning under sail, the bateau bobbing and dipping on the swells, a sailor never can tell where the winds are going to blow next.