Evidently, there were quite a few coins like mine. I guess my father got his from a magazine. Thanks for your input.
Yes, they’re relatively common, but quite historically appealing. These Admiral Gardner coins and the Spanish silver from the 1784 El Cazador wreck are some of the more available (and thereby more affordable) historical shipwreck coins on the market. And the inherent drama, romance, and tragedy of shipwrecks is fascinating, if you like your coins with a bit of history behind them, as I do.