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Need help identifying survey disk found on the beach in the Bahamas


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A friend sent me a photo of a benchmark disk that her parents found washed up on a beach in the Bahamas. (I let her know that her parents should contact the NOAA about the disk.)




It's stamped TIDAL NO 6 1960. I assumed that the mark came from Florida, but I can't find any tidal marks in the NGS database with that name, number, and year in Florida.


Any ideas where this one might have come from?



Edited by ePeterso2
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There is a separate database maintained by NOAA which is more inclusive as not all tidals have made it into the NGS database - here's a link http://tidesandcurrents.noaa.gov - it would be hard to identify this particular one other than by reading the details of the sheets along the Eastern coast of FL (I'm assuming) & looking for a description of a standard USC&GS disk being used (rather than a NOS disk) and stamping of 'TIDAL NO 6 1960'. Hard to believe a disk would roll along the bottom of the seabed to one of the islands ...but stranger things have happened!

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Hard to believe a disk would roll along the bottom of the seabed to one of the islands ...but stranger things have happened!


Agreed! I'm having a hard time coming up with a plausible explanation of either natural or human-aided means for it to have gotten where it ended up (in the far northeast corner of the Bahamas).


Thanks for the tip.

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The Coast & Geodetic Survey (USC&GS) did a significant amount of geodetic survey work in the Bahamas during the 1960s as part of the U.S. space program. The country has lots of USC&GS triangulation, bench mark and tidal stations across most of the inhabited islands. Unfortunately these data were never automated and added to the NGS database. By the time the DB was created this effort was long past and since these data were not in the U.S. and were not going to be part of the North American Datum of 1983 or the North American Vertical Datum of 1988 they were ignored. They still have paper records so if you contact CO-OPS as ERNMARK indicated they should be able to dredge up the old data for you.

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