Moore McCormack Lines, Inc., a subsidiary of Moore McCormack Resources, Inc., One Landmark Square, Stamford, Conn. 06901, has applied for a Title XI guarantee to aid in financing the reconditioning and reconstruction of six existing vessels.

Moore McCormack intends to modify the Mormacvega, Mormaclynx, Mormacargo and Mormacrigel, all 7,247-deadweight-tons Constellation-class vessels built by Ingalls Shipbuilding Corp., Pascagoula, Miss., and delivered in 1964 and 1965. A 115-foot cellular midbody section and three 40-ton cranes will be added and the No. 3 hatch converted and dedicated to cellularized containers, making each of the vessels self-sustaining cargo/container ships.

The company also intends to perform the cellular conversion of No. 3 hatch on the Mormacaltair and Mormacdraco, which had midbodies added in 1975.

All of the vessels are expected to be delivered in 1982, but no builder has been selected. Construction subsidy for the project has also been requested.

If approved, the Title XI guarantee would cover $31,875,000 or 75 percent of the estimated actual cost of $42,500,000.