This reply is to Vulcan,s post.
Take in to account and fully understand the level of capital required to search under the sea to retrieve these specimens and that the higher percentage of such specimens recovered are so deterioated from electrogalvanic corrosion and that Dan Sewick is purchasing these coins from - among other folks mostly divers who are just trying to offset the cost of their hobby and passion and - - - he has a right to attempt to cover his costs and an honest profit--- now the prices aren't so high.
What is even more relevant is his prices appear to be a result of the prices realized at public or internet auctions, not ebay, where most bidders are looking for - to -good-too-be- true deals... Actual coin auctions establish actual demand and both the Sedwicks Dan and his father always did a good job following this market place.
BUT, .... what do I know...