Petromar International, Ltd., P.O. Box 967, Rockport, Texas, has applied to the Maritime Administration for a Title XI guarantee to aid in financing the construction of six tug/supply vessels. The 193-foot-long, diesel-powered vessels are being built by Halter Marine, Inc., New Orleans, La., with deliveries scheduled through June 1981. They will be operated in the Gulf of Mexico.

The requested guarantee is for $27,300,000, or 87½ percent of the vessels' total estimated actual cost of $31,200,000.