An Anchor and rode were required for several distance races including the DTB and the C100.

The requirment was dropped because the size anchor that could be reasonably carried was not adequate to hold the boat off a lee shore. (/search for post by Rick Bliss experiene)

Some regions required an anchor based on big boat monohull experience. They reasoned that an anchor would be used to stop you from drifting into a shipping channel. They did not realize that a cat can be paddled quite efficiently and anchoring would not be necessary.

Most find that an anchor is used to keep the boat off the beach for lunch.