The Korean turtle ship can't go into oceans?

They could capture a turtle ship with a privateer.

joncnunn said:

Turtle ships really want to be the replacement for Privateers, if they did replace those instead of the Caravel (the ocean going exploration vessel) there would be fewer complaints.

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That might depend on the type of game you play. Privateers are very well liked for war, as you can expand your navy very easily with a few of them. Caravels are only useful for early exploration and become fairly useless after. Privateers remain good until they are replaced, which is best to amass a large fleet of them for upgrading to retain their special perk.

Uzael36 said:

That might depend on the type of game you play. Privateers are very well liked for war, as you can expand your navy very easily with a few of them. Caravels are only useful for early exploration and become fairly useless after. Privateers remain good until they are replaced, which is best to amass a large fleet of them for upgrading to retain their special perk.

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Point taken that if the Turtle boat replaced the Privateer that it would eliminate the ability of Korea to capture ships.

So maybe if the Turtle boat replaced the Iron Clad with the same stats as an Iron Clad, but able to be built early (Astronomy) and still not require resources it would make everybody happy even with a no deep water promotion.

(The Turtle Boat is basically fulfilling the Iron Clad role, but with a longer shelf life since it starts earlier)

In my own games, I use Caravels to find all remaining natural wonders and city states I hadn't earlier and that takes awhile.