The D.C. statehood convention moved yesterday to unplug a potential logjam of cases before a "Supreme Court" in its proposed constitution by authorizing the legislature of the proposed new state to establish an intermediate appeals court.

Convention delegates, taking a second look at their judiciary article, voted 19 to 8 to let the legislature create the additional court if it determined that the two-tiered court system, approved earlier by the convention, could not handle the caseload.

Originally, the convention approved creation of a 44-judge Superior (or trial) Court and a nine-member Supreme Court, similar to the present court structure here. A major difference, however, is that nine Supreme Court justices would hear all appeals en banc, or as a group, rather than in panels of three judges each, as the present D.C. Court of Appeals does.

Several delegates warned that the already logjammed D.C. Court of Appeals would become even more heavily burdened if its nine members had to hear all cases en banc.

Other delegates countered that the legislature would be empowered to create "inferior" courts--such as tribunals for settling neighborhood disputes--and many of the appeals from those courts could go to an appellate division of the Superior Court, thus reducing the caseload ultimately going to the Supreme Court.

But Ward 2 Delegate Alexa Freeman argued yesterday that an "extremely serious problem" still would remain, and the convention went on to approve an intermediate appeals court provision.

The convention, with less than a week to finish writing the constitution, also tentatively approved a series of health, housing and human services provisions. But delegates wrangled over which provisions to require by constitutional mandate and which to leave to the discretion of the new state's legislature.

Delegates, for example, changed one section that originally said the "state shall have the power to provide" prison facilities to say more bluntly, "The state shall provide" such prisons. They made a similar change in a child day-care provision.

But other provisions, such as those for unemployment and workers' compensation, low-income housing and economic security for the elderly, were left to be created at the discretion of the legislature.

The convention has until May 29 to finish its task. The last article--a proposed bill of rights--will be debated Monday. Second and third readings of other articles, plus editing of the entire document, are scheduled to be completed later in the week.