The Hook That Was Never Tested This Way: CV30 and the Southern Ocean MOB

Clipped On, and It Wasn't Enough

On 18 November 2017, a crew member aboard the Clipper Round the World Race yacht CV30 was working the foredeck in rough Southern Ocean conditions, tethered to a jackstay as required. The tether hook snagged on a jackstay termination cleat and became laterally loaded — pulled sideways rather than along its length. Under that load, the hook's gate opened with a force far below its rated longitudinal strength. The crew member went overboard. The crew attempted recovery for several hours. He was not recovered alive.

The Loading the Standard Never Tested

MAIB's investigation found the tether hook had done exactly what its design standard required — it just wasn't laterally loaded when tested. ISO standards for safety tether hooks covered longitudinal loading only. The lateral loading vulnerability that opened this hook was not addressed anywhere in the standard it was certified against. The equipment had not failed to meet its specification. The specification had a blind spot nobody had closed.

A Cascade, Not a Single Failure

Behind the hook failure, MAIB found a chain of contributing gaps: jackstay termination arrangements that allowed a hook to snag in the first place; secondary jackstays on the Clipper 70 design creating additional snag points; tethered MOB recovery training that was not compulsory before each leg; and ongoing vessel maintenance issues that had increased crew workload in already difficult conditions. Clipper Ventures' safety management system had not identified foredeck operations in severe weather as a specific high-risk scenario requiring its own procedures.

Recommended Actions

1. British Standards Institute: Review and amend ISO 12401 and ISO 15085 to address lateral loading hazards of tether hooks and jackstay termination snagging risks (Rec 2019/110).
2. World Sailing: Raise awareness of the dangers of laterally loading safety tether hooks and consider amending the Offshore Special Regulations (Rec 2019/111).
3. Spinlock: Review and amend user instructions for safety tethers to emphasise the dangers of hook snagging and lateral loading (Rec 2019/112).
4. Clipper Ventures: Review and modify risk assessments and SOPs for foredeck operations, reducing sail in rough weather, and MOB recovery procedures (Rec 2019/113).
5. Clipper Ventures: Review and amend yacht maintenance processes to minimise crew workload during the race by ensuring yachts are free of material defects at the start of each leg and fully maintained during stopovers (Rec 2019/114).

Human Element Analysis