The classic underwater archaeology grid is featured on this 1987 'Historic Shipwrecks' FDC with a rather dubious scale..! The top right stamp shows San Juan's hull which sank in 1565 in Red Bay.
From the early 15th-early 17th cent. Red Bay was home to Basque whaling stations. A cancelled cover, prior to UNESCO designation.
Above is era pic I took of the Bay... in July!
2015 Red Bay PSP from the 5v UNESCO set of USA and international rates.
The 2017 domestic issue from a 5v s/s. This is the final set of the UNESCO series, a shame they didn't do one more year and show places on the 'tentative' list.