The governor shall appoint three examiners to constitute the Board of Examiners of Bar Pilots for the Port of New Orleans, all of whom shall be bar pilots and shall have served as such for a minimum of five years preceding their appointment at the entrances of the Mississippi River into the Gulf of Mexico or the entrance of any other waterway connecting the City of New Orleans with the Gulf of Mexico or other outside waters; the examiners shall hold office for four years or until their successors are appointed and qualified, and shall perform their duties without compensation.