Ansley W. Sawyer wrote:

trap lines and toggles. But I was wrong! I found that when a line
went under the keel and the buoy was along side of the boat sometimes
the buoy would be pulled under and it would wrap around the cable and
secure me well to the trap.

This confirms my expectations about the arrangement. If there is any
leeway, which will be the case anytime you are not dead downwind, there will
be a vortex trailing off the keel tip. Anything floating will tend to
follow this vortex which can be quite intense as described in my other
response above. There is the potential for a floating object to go around
a rope aligned closely with the center of the vortex several time. What a
mess!

--
Roger Long