Eternal2

When this ship sinks, do not remove it from the game. Instead, place it docked with no masts at your home island; its crew remain onboard but any treasure or other cargo (including equipment) that it carried is treated as if the ship sunk normally. You may repair the ship as normal at your home island. When a sea creature with this keyword is eliminated, do not remove it from the game. Instead, place it docked with no segments at your home island; it may then be given repair actions (like a normal ship) until it leaves your home island.

Sea Monster2

A ship with this keyword printed on its deckplate card is a sea creature. At the beginning of your turn, decide if the sea monster is submerged or on the surface. If submerged, a sea monster can only move; it cannot shoot or be shot at, and it cannot dock or touch other ships. If a sea monster is on the surface, it may move or shoot like a normal ship. It may ram opposing ships (the rammed ship becomes pinned instead of the sea monster) and it may board. After winning a boarding action the sea monster may eliminate a crew or steal a treasure (if cargo space permits), but it cannot capture crew and if it takes a unique treasure that treasure is eliminated.