CHATHAM, MASS. -- Ron Wilson stood on what remains of the patio in front of his seaside cottage here and marked off the distance to its crumbling, concrete edge.

"We got about eight feet left -- that's it," he said.

In this sun-swept town on the elbow of Cape Cod, where the clapboard buildings on Main Street haven't changed since World War II, property owners along the coast are struggling with a simple but brutal truth: Time never really stands still.

Nature made the point in dramatic fashion on Jan. 2, 1987, when the Atlantic Ocean punched an opening through a barrier beach about a half mile from shore during a fierce winter storm, exposing the once-protected coast to change.

Even then, Wilson and his neighbors hoped change would pass them by.

The following spring, when his cottage was still separated from the ocean by about 100 feet of dunes, Wilson spent $30,000 on improvements to the cottage.

But after storms hit in September,

ocean water blasting through the breach in the offshore barrier devoured up to 150 feet of land in just four months, according to property owners. Then on Jan. 21, the cottage next door to Wilson's toppled into the sea.

A coastal engineer who lives in Longwood, Fla., most of the year, Wilson should have seen it coming. But he said plans to retire with his wife to the cottage that his father-in-law built in 1948 kept him from believing the ocean would threaten his piece of paradise.

"You just tend to be optimistic," he explained.

The Wilsons and eight of their neighbors have not given in to the forces of change despite the fate suffered by the Galanti family, owners of the cottage lost to time and tides.

Instead, they have pooled their savings to build a stone barrier -- a structure of questionable legality -- to try to prevent the ocean from eroding their dreams.

On most mornings since late December, a dump truck carrying huge boulders, some as large as six feet long, has rumbled down Holway Street and emptied its load onto the narrow beach. Then a roaring, diesel-powered backhoe has moved the stones in front of the seaside cottages.

The manmade barrier is more than 1,000 feet long and already about six feet high. When it's finished, Wilson said, it will stand 12 feet and may cost as much as $400,000.

"The big rocks cost big bucks," he said.

But state officials monitoring the disappearing ocean front could order cottage owners to remove the boulders before the end of this month.

Gary Clayton of the Massachusetts Department of Environmental Quality Engineering said the state generally disapproves of barriers like the one going up here because they often accelerate erosion at adjacent properties and can cause sand to block nearby waterways.

The barrier here "could be directly at odds with what we're trying to balance," Clayton said.

Furthermore, some officials believe that, in the long run, the stone barrier may not save the cottages.

On Jan. 27, property owners filed a $10 million lawsuit against the state, contending that state regulations generally prohibiting wall barriers resulted in the loss of their land, amounting to an illegal seizure of their property.

The property owners began building the stone barrier here under an emergency court order. That order, however, said state agencies retained the right to review the barrier and required property owners to post a $100,000 bond in the event that the state does not approve of the manmade structure.

"The erosion has not stopped," Clayton said. "I think the evidence is in what you're seeing before your very eyes."

Town officials and scientists in the area say this isn't the first time the ocean has crashed through Nauset Beach, the offshore sand bar that protected the shoreline here until a year ago.

Douglas Wells, chairman of the town Conservation Commission, said a two-block area of land was washed away by the ocean in the 1850s.

"Probably three or four roads were lost and 15 to 20 homes were either lost or moved," he said.

Graham Giese, a scientist at the Woods Hole Oceanographic Institution, said the last significant break in Nauset Beach occurred in 1846, adding that major breaks are part of a 150-cycle.

After a breach, Giese said, the barrier beach south of the new inlet gradually breaks up. At the same time, the beach to the north of the inlet grows in a southerly direction until the original length of barrier beach is replenished.

But a decade may pass before the cottages at the end of Holway Street are protected again.

"You generally think in terms of about 10 years in Chatham," Giese said. "This is a long process. It's not just this winter."

For the Galanti family, owners of the cottage lost to the sea on Jan. 23, the break in Nauset Beach was the beginning of the end of a way of life.

Paul Galanti, a 49-year-old law professor in Indianapolis, and his extended family have spent part of every summer in Chatham since 1945, the year of his seventh birthday.

"I remember standing on the steps of the Mayflower Shop on V-J day and everyone was cheering," he recalled in a telephone interview. "There's been almost no change on Main Street since I was a boy."

Galanti said he and his wife can't afford to rebuild on another plot in Chatham, where ocean-front property that sold for less than $1,000 in the 1940s can cost several hundred thousand dollars today.

And it will take a while before the Galantis can face returning as tourists to walk down Holway Street to the unforgiving sea and the changing shore.

"It's grief," Galanti said. "When the cottage went, a little bit of me -- or maybe a lot of me -- passed away."