Are artificial islands effectively unsinkable compared with ships?
Short answerThey are harder to remove, but poor construction or damage to critical structures can let the sea undermine them.
NotesAn artificial island cannot be sunk like a ship, but its durability still depends on very good concrete and the quality of the reclaimed structure. Damage in the right places can let the sea do much of the destructive work. Permanence is therefore an engineering problem, and newly created land is not automatically an unsinkable military base.