sentences:  All scientific dives must be under the supervision of a registered diving supervisor of a class appropriate to the specific diving operation.Most scientific diving in South Africa is done on open circuit scuba by Class 4 and 5 divers as no-stop dives on air or nitrox.The Code of Practice for Scientific Diving allows for the use of alternative modes and technologies provided appropriate competence is achieved by training and assessment, and the risk of the project is assessed as acceptable by both the organisation and the members of the diving team.