The friends of Captain McDonald, master of the brig Robin-Hood, will be sorry to learn of the rather serious injuries which he sustained on the voyage between Kaipara and Sydney. We understand that a tremendous sea broke over the vessel, carrying away the boats and deck houses, as well as smashing the cabin skylights and bulwarks, and a large piece of the debris struck Captain McDonald with great force, rendering him perfectly insensible, in which state he remained till Sydney was reached, four days later. Upon arriving, Mrs. McDonald, who was a passenger on board, procured medical assistance, and the latest advices intimate the favourable recovery of the captain. The damage done to the vessel has rendered it necessary to have her docked, and her cargo has been discharged, and is now being disposed of in Sydney in place of Melbourne, to which port she was bound till stress of weather forced her to run to Sydney for shelter.