Decision Simulator

CV30 — The Snagged Tether

CV30
Racing yacht (Clipper 70) · Southern Ocean, approx. 1,500nm west of Fremantle, Australia · 18 November 2017
Source: MAIB Report 7/2019

3Decision Points 3Possible Outcomes —Avg. Play Time

The Situation

You're on the foredeck of a Clipper 70 ocean racing yacht, roughly 1,500nm west of Fremantle, deep in the Southern Ocean. Conditions are rough. Before you clip on and head forward to help with sail handling, you notice the jackstay terminates at a cleat with exposed hardware — the kind of point a tether hook could snag on.

The Lesson

Safety equipment that protects against one failure mode may be vulnerable to another that isn't tested or specified in its standard. Jackstay terminations must be arranged so a tether hook can't snag and be laterally loaded in the first place.

Human Element

Safety tether hooks were assumed to work as designed, but the lateral-loading failure mode that let this hook open under a relatively small force was not covered by the design standard — and was therefore invisible to the crew relying on it.

Try the First Decision

The cleat at the jackstay termination is exactly the kind of snag point that can laterally load a tether hook. You've got a moment before heading forward.

A. Rig temporary protection over the cleat — tape or a wrap — before clipping on and going forward

B. Clip on and head forward — the hook's rated for this, and there's sail handling to get on with

This is a preview — the full scenario branches from here based on what you choose, with real consequences and a debrief at the end.

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