If red then it indicates that it is a port-hand buoy and must be kept on your port side when entering a harbour or going up a river estuary.
Ukuba ibomvu ibonisa ukuba ingumqondiso obhabhayo wengozi kwisandla sasekhohlo senqanawa kwaye kufuneka igcinwe kwelo cala xa ingena ezibukweni okanye xa inyuka kumachweba omlambo.