If I had to choose between a trustworthy anchor and a trustworthy rig, I'd take the rig everytime.
Keeping the rig up and the water out are the foremost important issues. You can always 'get by' with multiple unsavory rodes and anchors, but If the rig goes it's game over.
I really don't see how an anchor is considered a safety device. It seems like something that is used regardless of the situation shouldn't be considered a safety device.
The question was, "the one piece of safety equipment".If I had a gps I wouldn't be lost in the first place.When the mast has gone over the side,the radio would be useless.The EPIRB is it,go buy one,not one of those silly spot things either.
__________________
s/y Elizabeth— Catalina 34 MkII "Man must have just enough faith in himself to have adventures, and just enough doubt of himself to enjoy them." — G. K. Chesterfield