PORTSMOUTH — Those with moorings from Black Point to McCorrie’s Point along the Sakonnet shore and around two-thirds of Prudence Island may have to ship out to another spot.

The town has been illegally issuing moorings for the past two decades in what the Coastal Resources Management Council classifies as pristine or Type 1 waters that do not allow the placement of moorings or construction of docks.

Assistant Town Planner Gary Crosby told the Town Council at Monday’s meeting that there are about 77 moorings in Type 1 waters, which extend 500 feet out from the shore. This represents just under 10 percent of the 878 moorings registered in 2008.

Mr. Crosby said there are 42 moorings permitted in Type 1 waters on Portsmouth’s east side, and 35 moorings in Type 1 waters around Prudence Island. Almost two-thirds of the water around Hog Island is Type 1. Mr. Crosby says there are 15 moorings in those waters, but that they are most likely permitted to riparian owners — property owners whose boundary extends to the mean high tide mark — which the CRMC regulation does not apply to.

In Portsmouth, Type 1 waters run from north of McCorrie’s Point south to the Middletown line. Type 1 waters in Prudence Island start at Mill Creek and extend north to below Potter’s Cove; then Type 1 waters are designated from north of Potter’s Cove around the northern and western part of the island to just past the Prudence Conservancy land; a section of the Prudence Conservancy property is classified as Type 2 (which allows moorings, docks, rip rap and bulkheads), but Type 1 waters begin again at the southern edge of the Conservancy land and run around the southern tip of the island and up to a point south of Sand Point. Potter’s Cove and Sand Point are in Type 2 waters. Moorings in waters that are out 500 feet or more from shore are in Type 2 waters.

The issue surfaced about six months ago, Mr. Crosby said, as he and the Harbor Commission worked with CRMC to update the Harbor Management Plan, which hadn’t had a review since 1993.

After Monday’s meeting, Mr. Crosby said that the town has known that it was permitting moorings in Type 1 waters, and that CRMC probably knew as well.

These moorings may have to move to Type 2 waters. Mr. Crosby says there are open mooring areas in town but the problem is ensuring that there is public access available to the new spot, Mr. Crosby said.

CRMC offered an alternative to moving moorings. The town can apply to CRMC to reclassify from Type 1 to Type 2. It would mean that moorings can stay, but also opens up the potential for dock construction, as well as rip rap and bulkheads — rock and concrete used to stop erosion at the shoreline.

“We have to make the case that it’s not going to result in a negative impact, i.e., every house in the place is going to ask for a dock,” Mr. Crosby said.

Judi Staven told councilors that she is concerned that shore-side residents will take advantage of a change in the classification to build a dock, and that will impede public access along the shore.

“The majority of people in Portsmouth do not live near the water,” Ms. Staven said.

Councilor Keith Hamilton asked Mr. Crosby if the moorings could be grandfathered in, eliminating the need to move moorings or reclassify the water. But Mr. Crosby said the CRMC regulations were in place (since 1983) before the harbormaster began keeping records of moorings.

Councilor James Seveney said that the town could show that the shoreline on Portsmouth’s east side has changed to mostly residential since CRMC designated the waters as pristine.

The council voted 4-0 (Jeffrey Plumb recused himself because he owns a mooring; Dennis Canario and Karen Gleason were absent) to have Mr. Crosby develop a plan for reclassification of the water. Once Mr. Crosby is finished with his plan, it will return to the council for review, and then will go to CRMC which will hold public hearings before making a decision.

Mr. Crosby suggested doing spot zoning in certain areas. These are preliminary scenarios: reclassifying the waters on the east side to Type 2, from north of McCorrie’s Point to south of Sandy Point; on Prudence Island, extending the Type 2 classification from Potter’s Cove south to Mill Creek. He said he will not include Hog Island in the request.