Recently while in W. Palm Beach Florida I noticed what appeared to be an abandoned a low Freq. beacon site on Flagler Avenue on a platform a short distance out into Lake Worth. It was about 80 Ft. tall, has a fence around it, and a copper grounding system going into the water. It aroused my curiosity and I imagine it was once used as a navigation aid to mariners. Does anyone know the history of this or know where I might look up marine beacons ? There is a lot of info available on low frequency aircraft beacons, but nothing that I could find about marine beacons.