Four men trapped in their ski-boat that was hovering at the edge of the Grootdraai Dam spillway in Standerton, Mpumalanga, have been safely rescued. According to the National Sea Rescue Institute (NSRI), the casualty boat, with the men’s personal belongings on board, remains trapped on the edge of the weir. NSRI spokesperson Craig Lambinon said the men’s ski-boat may have experienced motor mechanical failure and drifted to the edge of the dam wall at the spillway.
Heavy-flowing water threatened to wash them and their boat in a 40-metre drop into the Vaal River as they clung on. NSRI Witbank and Gauteng duty crews were activated on Monday at about 7.05pm. Lambinon said NSRI Witbank dispatched a rescue vehicle towing rescue craft Harveys Fibreglass (over the 140km from Witbank to Standerton).
NSRI Gauteng dispatched a rescue vehicle towing rescue craft Rotary Endeavour (over the 143km from Benoni to Standerton). He said members of the department of water and sanitation, the SA Police Service, Delta 1 Search and Rescue, Police K9 Search and Rescue, Mpumalanga Fire and Rescue Services, and Mpumalanga health EMS were on the scene but were unable to reach the four men, who were in the water clinging to their ski-boat at the edge of the wall. On arrival at the scene, Lambinon said NSRI Witbank launched Harveys Fibreglass between 3-4km upstream from the dam wall.
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“Unknown to NSRI, it appears that a department of water and sanitation member had opened three sluice gates at the spillway.” He said this action automatically created a vacuum beneath the casualty boat, relieving overflow pressure. This prevented the casualty boat from being swept over the edge but trapped the vessel. NSRI Witbank station commander Travis Clack explained that the initial approach was to ease power on the rescue crafts and two outboard motors, drift backwards with the stern towards the wall, where the boat motor’s power could be increased if it appeared that the NSRI rescue craft would be at risk of being trapped in the same vacuum (as the casualty boat) or risk being swept over the dam wall.
However, while drifting backwards towards the casualty boat, strong 12-14 knot winds caused the rescue craft to toss and turn. Clack decided to go bow ahead towards the casualties with reverse gears ready to be engaged. On approaching the four men, Clack said the NSRI rescue craft could be manoeuvred with a greater safety margin ― using this approach ― but it remained a calculated risk.
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