Sctts, you are correct. Sometimes treasure ships were held in port until the folllowing year. Usually Treasure Ships went out in large convoys for protection against Pirates.
In years when Treasure ships encountered Hurricanes and sunk. There are records of those losses. The Spanish kepy a record of every ship. The only records that I know about where Spanish Treasure Ships were lost in Hurricanes, were the years. 1589, 1605, 1641, 1715 and 1733. Although there may be other years. Also a FACT that is to every treasure hunter. Is that Spain sent out salvage boats to try and locate lost sunken treasure ships and in most cases, they were successful in recovering part of the lost treasure.
I wish sfrx luck and I hope they hit it big.
Just my personal opinion