Charles A. Gambrill Sons, a family partnership here, has purchased the 210-acre Calvert Marina property in Solomons Island, Md., for $2.95 million.

Formerly the World War II naval amphibious training base at Solomon's Island in southern Calvert County, the property was purchased from a partnership headed by Dr. Lloyd Hazleton. H. G. Smithy Co. was the broker.

J. Matthew Gambrill, a partner in the new ownership, said that the marina has 300 boat slips and two miles of waterfront across the Patuxent River from the Patuxent Naval Air Center, which is still in operation.

Gambrill said the new ownership plans to rent empty boat slips and improve the property, possibly as a primary and vacation home site for a marketing public expected to include persons who have served in the Navy in that area.

Previously, the Gambrill family owned the Wyatt Building on 14th Street NW, which was sold two years ago to the National Association of Realtors for $8 million. The family earlier owned and managed the Investment and Longfellow office buildings and the Patrick Henry, Bradley Boulevard and Tyler Gardens apartments, some of which have since been converted into condominiums.

Gambrill said that "office-building don't make sense anymore to us as a buyer, so we had to start being a little innovative in a kind of investment [the marina] that is new to us."