Cache is not at the listed coordinates but is located within 100 ft.
So while walking along the Harbor Walk, I figured I might find an unlisted benchmark. Well sure enough I found one! Then it gave me the idea for this cache. So you must do the same thing. At the posted coordinate, locate the small benchmark labeled "CAIT 719". You can find it on top of the stone that lines the channel within 25 ft of the posted coordinates. A simple step off the path and you should see it. To locate the cache, take a coordinate reading then use these offsets, N -.014 W +.004. That should bring you to the area where the cache is.
Congrats to ritell for FTF!