Answer:

galleons

AnswerCrossword Clue
GALLEONSMerchant ships of old
GALLEONSMain transportation?
GALLEONSShips of the Spanish Main.
GALLEONSThey sailed the Spanish Main.
GALLEONSArmada ships
GALLEONSOld treasure transporters
GALLEONSMany Spanish Armada ships
GALLEONSShips of Spain
GALLEONSLarge Spanish ships of old
GALLEONSSpanish merchant ships of old