The Martha's Vineyard Commission acted swiftly last night to set in motion a plan that could preserve the north shore between the West Chop and Gay Head lighthouses as it is today - pristine and virtually free of any piers, docks or groins.

Commission members voted unanimously to nominate the coastline stretching across four towns as a district of critical planning concern (DCPC). An automatic building moratorium is now in effect. The MVC will now have to set a date for a public hearing before voting whether to designate the district.

"It feels like we crossed the first milestone," said Judy Crawford, the chairman of the West Tisbury conservation commission who helped to launch what has been dubbed the Wild and Scenic North Shore DCPC.

If the DCPC designation wins ultimate approval by the Commission, the protected area would cut a 100-foot wide strip along the coastline, from low mean water mark and out to sea, from West Chop Light to Gay Head Light. The intent is to keep this area free of any construction such as piers or swimming docks.

A regional initiative, the nomination came with the backing of conservation commissions in Tisbury, West Tisbury, Chilmark and Aquinnah. Mrs. Crawford feels buoyed by the support this conservation effort is receiving from town leaders and from stakeholders along the north shore. "For me it's almost like motherhood and apple pie; there's very little not to like about this," she said last night.

But landing a DCPC designation takes some work. If the commission votes to establish the district, what follows is a year of planning to lay down the exact regulations for adoption.

"Now you've got your homework to do," commission member Michael Donaroma of Edgartown told Mrs. Crawford last night.

And already, commissioners started to point out some details that should not be overlooked. Commissioner John Best of Tisbury warned that the 100-foot stripe should not just cover surface area. "It's got to take into account the airspace above it," he said. "We've had cantilevered piers proposed in Tisbury."

To be sure, work lies ahead for the conservation commission members who plan to shepherd this project through to completion. "Ultimately, it's the people who will decide these regulations," said Mrs. Crawford. "That's what's great about this process."

Environmental concerns will figure heavily in their actions. "From a conservation point of view, there is eel grass along North Shore, and while it may not be in the first 100 feet, it migrates from time to time," said Mrs. Crawford. "The minute you put one of these structures in the water, it's easy to see the death of the eel grass." Without eel grass, shellfish habitats are endangered.

But scientific concerns are only part of the picture. There's a strong desire to protect the visual beauty of the north shore in its unspoiled state. "The north shore is just about the last stretch of pristine land on the northeast coast," Mrs. Crawford told commissioners. "And we believe that should be protected."

The handful of piers and docks that line the shore now would be grandfathered, but the goal of this proposed DCPC would be to prevent any new construction along this coastline.

This regional effort to freeze the clock along the north shore got its first start several years ago when some landowners began working with conservation groups to establish a set of voluntary covenants that would have restricted piers and other structures from the shoreline. That effort fizzled even though many residents embraced the idea.

Then, last year West Tisbury resident Steven Rattner galvanized opposition to piers along the north shore when he tried unsuccessfully to win approval for plans to build a permanent wooden pier on the beach between Paul's Point and Cedar Tree Neck. After review by the MVC as a development of regional impact, Mr. Rattner's pier plan was rejected.

In its ruling against the pier, the commission wrote that it did not want to "risk irreversible damage to a state-designated barrier beach by having a development such as this permitted." A lawsuit filed by Mr. Rattner is appealing the commission decision.

Mrs. Crawford is not anticipating serious opposition to the proposed DCPC protecting the north shore. Indeed, a major aspect of the proposal is that it does not intrude on any private land. Commissioner Linda Sibley of West Tisbury pointed out that this would be the first DCPC that did not affect privately owned land.

The proposed DCPC would also allow for grandfathered fishing rights and for maintenance to piers already in existence. There could also be allowances made to encourage future aquaculture ventures along the shoreline, said Mrs. Crawford.

While acknowledging that docks might make some people's lives a little more convenient, she said, "If you weigh that against the beauty of the north shore, it's hard to come out in favor of the other side."