The Maritime Administration has approved in principle an application from Goodyear Steamship Company, Buffalo, N.Y., for a Title XI guarantee to aid in financing a self-unloading bulk carrier for operation on the Great Lakes.

Bay Shipbuilding Corporation, Sturgeon Bay, Wis., expects to deliver the 634-foot-long, 23,445-dwt vessel in April 1981. The Title XI guarantee will cover $27,476,000, or 87½ percent of the bulk carrier's $31,701,434 estimated cost.