A new joint venture by New Orleans-based International Shipholding Corp. and Cooper/T. Smith Stevedoring Co. of Houston is building a hub terminal to transfer cargo between barges and surface carriers at Memphis, Tenn.

The innovative concept for non-containerized cargo handling first surfaced publicly last June during a breakbulk cargo conference speech by an executive with ISC subsidiary Waterman Steamship Corp.The jointly owned company, LASH Intermodal Terminal Co., is expanding an existing Mississippi River Terminal to provide a covered cargo transfer terminal for the barge-carrying vessels called lighter-aboard-ship, or LASH, operated by Waterman and two other ISC subsidiaries, Central Gulf Lines Inc. and Forest Lines Inc.

The LASH Intermodal Terminal, to be managed by Cooper/T. Smith, is scheduled to open in May.

Terminal plans were announced Monday in a statement, but company officials could not be reach for further comment.

However, at last year's Breakbulk '91 Transpo conference, Theron Foote, Waterman's sales and marketing senior vice president, said non-containerized shipments of general cargo, known as breakbulk, have a strong future, but ''the steamship lines have to come up with the innovations" if they are to compete with the containerized market.

Mr. Foote said one such innovation will be the breakbulk hub operation that will allow the LASH mothership to dispatch its barges up the Mississippi to discharge cargo to motor and rail carriers and to load cargo that arrived by truck or rail for transit back down the river to the LASH vessel.

Barge transit time between New Orleans and the Memphis terminal is four days.

LASH International Terminal is expanding the former Rivergate Terminal under the long-term lease with its owner, the Rivergate Terminal Group, which is consolidating operations at its Mid-South Terminal on President's Island in Memphis.

LASH Intermodal Terminal officials believe the 237,000-square-foot facility will be the only mid-continent covered terminal of its size serving water, rail and truck traffic.

The expansion project will increase the terminal's existing 112,000-square- foot warehouse by another 125,000 square feet of climate-controlled space for all types of cargo. The enlarged warehouse will include indoor rail tracks, numerous covered truck bays and other covered areas for loading and unloading barges.

A 500-ton LASH barge crane will be installed to move the barges between the dock and the warehouse, as well as to perform other heavy lifts up to 300 tons.

Direct terminal rail service will be provided by Illinois Central Railroad, which also will offer connections with five Class I railroads serving Memphis, while interstate highways 55 and 40 offer immediate road access.

The terminal also will provide electronic date interchange, exterior storage, cargo weighing and sampling, customized crating and acceptance of full and less-than-bargeload shipments.