Opher,

That was my though as well after I had it slip Sunday. Replaced the cleat with a Harken 150DS=double springs which holds better but the issue is as stampede says, the 5mm FSE Robline Racing Sheet is compressing in the cleat and sliding. Doesn't help that this line is a bit slippery to begin with. Runs really nice though; for a change the spinnaker setup is running smoothly.

Upwind it's not an issue for me; using Tripp and Mike's bungee takeup system, if the halyard isn't cleated upwind it's no big deal, enough tension exists to keep it free of the spreaders.