On Mon, 5 Nov 2007 13:48:47 -0500, "Roger Long"
wrote:

Look at a proper chain hook and then at a mainsail reefing hook. Ponder the
cross sections, the material, the anticiapated loads. You won't sleep with
a reefing hook holding your boat in a blow after that.

Exactly right. The chain hook, shackle and hookline all need to be
sized to approximate the Safe Working Load (SWL) of the chain itself.
You really don't want to be losing your hookline under a heavy strain.