Gresham Marine Surveying, Inc., headquartered in Savannah, Ga., has opened operations serving the Savannah, Brunswick, Charleston, and Jacksonville maritime communities. Capt. Jeffrey T. only a few marine surveyors in the world currently providing the draft/freeboard indicator service. 1/16th of an inch. as being indispensable for calculating displacement tonnages on barges and bulk carriers. not affected by sea and swell," said Capt. Jeffrey Gresham. and tanker ROB surveys. The company also provides expert witness services. concerned parties," said Gresham.