Modular structure for protecting an offshore vessel in a body of water from forces of ice features in the body of water is described. The modular protective structure comprising a protective harbor wall constructed and arranged to enclose a harbor space and to counteract the forces of ice features in the body of water. The modular protective structure also comprising a flotation support supporting the protective harbor wall. The flotation support having a capacity to position the modular protective structure at a raised position where the flotation support maintains at least a portion of the protective harbor wall above the water surface such that a harbor is established and the offshore vessel is protected from the forces of ice features in the body of water. Methods which utilize such a modular protective harbor structure are also described.