7 years ago on a charter out of Raiatea, we were approaching the Bora Bora yacht club and an employee dinghied out to help us hook up. I was at the helm, so didn't see this but reconstructed from what my son later told me:

The Leopard 40 was set up with a bridle and a large snap hook. The mooring pendant was of very thick rope and the gate of the snap hook would not open wide enough to pass the this rope through, so the chap from the yacht club passed the snap hook through the eye of the pendant and clipped it back to the bridle rope. Tension pulled the connection below the surface, so I never saw what he had done.

The next morning, I found the snap hook, gate open, with just the tip hooked precariously on the strands of the eye of the mooring pendant. Being side-loaded, it had unclipped itself from the bridle and on it's way through and out of the eye it had caught on the mooring rope, that tenuous connection being the only thing that kept us from going adrift during the night.