Deep Sea Adventure: Kaitei Kyuu Panthalassa no Nazo (1997)

Your father has mysteriously disappeared while carrying out his ocean studies. You, a young boy named Chris, must venture forth in your minisub and search for poppy. Explore underwater wreckage in a submarine which may be upgraded with better equipment in your search for sunken treasure. Equipment and exploration budgets may be filled to capacity if the coffers are enriched with newfound treasure. Encounter undersea cities, denizens and battle enemy pirates in this 3-D adventure.