South Africa's Department of Defence has confirmed that three people were killed while one other individual suffered less severe injuries after they were swept off the deck of a submarine off the coast of Cape Town on Wednesday, September 20.
The accident occurred as a South African Air Force helicopter was conducting a vertical replenishment, or providing resupply by airlift, of the South African Navy Heroine-class submarine SAS Manthatisi in rough seas just off Kommetjie on Wednesday.
A large wave struck the submarine during the replenishment operation, and seven crewmembers who were standing outside were swept off the deck and into the water.
The navy, the air force, the country's National Sea Rescue Institute (NSRI), and other partner agencies immediately launched a search and rescue (SAR) operation that led to the recovery of the seven navy personnel. Tragically, three of the personnel were later pronounced deceased.
The four surviving sailors as well as a helicopter crewmember who assisted in the SAR operation as a swimmer have since been brought to hospital. One of the sailors is in critical condition.
The defence department added that there will be an inquiry into the accident and the subsequent deaths of some of the personnel involved.