"James" wrote
Holds the boat away from the dock when it is not in use. Handy for docks
with rough water.

That's exactly what I've got and why I'm interested. I'm on a river, near a
turn-around point, and on summer weekends, the cruiser drivers start heading
home for dinner around dusk with their throttles in the "dead plow"
position, making about 10 knots at 30gph with wakes you could surf on.

The fiberglass mooring whips are cheaper if you have a boat under 25'.

Mooring whips seem awfully expensive to me, for what they are. ($300+ for a
pair of fiberglass fishin' poles?) Plus I've seen several broken whips
hanging off docks in my area. These things I saw (do they have a name?) were
on a small runabout, maybe 17' or so. Looked like something a reasonably
handy man could fabricate for himself at a reasonable cost.