Tier system is a system that judges the certain ship to have certain parts or traits to do certain tasks required for that tier. Normally it is impossible to upgrade a tier unless captain has upgraded its ship through the country power for example ( research breakthrough and etc), modified under the shipyard, risky situation like forcefully install a huge cannon on the shipThe tale has been illicitly lifted; should you spot it on Amazon, report the violation.


    Through other hidden methods and etc, it is possible to rank up the tier, After Tier 5, it may choose to change into other class


    Destroyer class


    Tier 0 Raft


    Tier 1 Sampan and Boats


    Tier 2 carvels, Carrack, Barge


    Tier 3 Junks, Galleon, Frigates, Triremes, Yachts, Man of wars


    Tier 4 Steamboat


    Tier 5 Steamboat with metal cover and lower hull base, ironclad