"Capt. JG" wrote:

Roger Long" wrote:
please tell me why standard snap shackles shouldn't be used
for safety harness tethers, at least on a casual cruising boat where
midnight headsail changes and spinnaker dousing isn't part of the normal
drill?

Hard to undo quickly, especially if you have to switch tethers when moving
around... I can't think of any other reason.

There have also been a few reports to the effect that a rescuer's
grabbing on the line of a crew-in-water attached to his or her harness
by a snap shackle with a short string attached to the movable pin, a
not uncommon ease-of-opening device attached to such shackles, might
accidentally open the shackle (too easily) - not a happy occurrence,
if the now floating away COB is not fully conscious.