CAPE TOWN, South Africa—Three South African navy personnel died and a senior officer was in critical condition after seven crew members of a submarine were swept off its deck by big waves as a helicopter attempted a “vertical transfer” of supplies, the Department of Defence said Thursday.
Wednesday’s accident happened as an Air Force Lynx helicopter was attempting what’s known as a “vertrep”—or vertical replenishment—of supplies to the SAS Manthatisi submarine on the ocean surface off the coast of Cape Town, the department said.
