Gov. Harry Hughes today outlined a series of stopgap measures to alleviate overcrowding in state penal institutions, which he conceded may require construction of a second new prison.

In addition to a 720-bed facility already authorized for Hagerstown, Hughes said he has approved converting a vacant building in Hagerstown to house 150 prisoners and probably will have to permit housing another 300 prisoners in World War II-style quonset huts in the western Maryland city. Hughes also said he is considering placing additional inmates at the Brockbridge Correctional Facility at Jessup.

Hughes, who came into office three years ago opposing any new prison construction, backed further away from that position today, saying at a press conference that he does not oppose a study to see if an additional prison is needed. But Hughes added, "It is my hope that it won't be."

Corrections Secretary Thomas W. Schmidt told a House subcommittee last week that the General Assembly should consider authorizing construction of another prison, in addition to taking the steps proposed today by Hughes.

Critics of the governor's corrections policy said his latest recommendations seem to represent a quick-fix solution to a problem that they warn will grow worse as stricter parole policies and harsher sentencing cause the inmate population to continue expanding.

"It's like a Band-Aid," said Sen. Victor L. Crawford (D-Montgomery), who chaired a Senate subcommittee on prisons. Crawford called the latest proposals a "stopgap measure . . . . It's obvious we're busting at the seams. There's no doubt we're going to need a new prison, no doubt."

Hughes said today that while no final decisions have been made on the Brockbridge facility and the quonset huts, he has given the go-ahead on converting a building in Hagerstown that had been used as a prerelease work center until the program was canceled in Washington County.

The governor's latest recommendations are considered a crucial, if short-term, solution to the long-running dilemma of inadequate prison facilities. A federal judge has ordered the state to end overcrowding, which has resulted in some prisoners doubling up in cells and others being housed in trailers.

Hughes said the overcrowding came about because, while the number of new prisoners has increased, the number being released has dropped off drastically. He said "there has been a dramatic increase in the length of sentences."

Critics blame Hughes for originally refusing to support a new prison, choosing instead to follow the advice of Gordon Kamka, the reformist former corrections secretary, who advocated work-release and more lenient parole as the way to solve overcrowding.

"Secretary Schmidt has reversed that trend," said Clyde Moser, president of the Hagerstown prison guards' union. "He is keeping them in longer, so we cannot now complain."

The new prison already planned at Hagerstown is the subject of a court suit, brought by Del. Paul Muldowney (D-Washington County), who charges that Hughes is taking a short-cut around normal contract procedures in awarding the construction rights for that facility. A House prison subcommittee wants to prohibit spending the $13 million for that facility until the court suit is settled, but Hughes is fighting that move.

"I think this means they realize that we need a whole new institution somewhere in the state," said Sen. Victor Cushwa (D-Washington County), another Western Maryland legislator seeking to stop further prison construction in his county.