Inspired by the first comment here, and considering they are called "boats", do flying boats carry anchors?
For pre-flight, the FAA says:
Check that necessary marine and safety equipment, such as life vests, lines (ropes), anchors, and paddles are present, in good condition, and stowed correctly.
(wikimedia.org) Nose access on the Albatross.
The answer seems yes.
Yes, if mooring the aircraft in open water.