🔍 Key Concepts

• Great Lakes load line marks are based on seasons and water density, similar to but not identical with ocean Plimsoll marks. • Common marks use letters like S, W, I to represent different seasonal freeboards. • Ask yourself if terms like "maximum submergence" or "mean sea level" are ever used as lettered marks on a Plimsoll/load line disc.

💭 Think About

• Look at the other letters shown in the illustration (S, I, W). What do those usually stand for on any load line mark? • If S often means Summer and W often means Winter, what kind of word starting with M would logically fit alongside those seasonal marks? • Which answer choices describe a season or loading condition tied to a season, and which are just generic physical descriptions?

✅ Before You Answer

• Confirm that load line abbreviations on Plimsoll marks normally refer to seasonal zones (Summer, Winter, etc.) or water types (Fresh Water, Tropical, etc.), not to things like "maximum submergence". • Check that the meaning you pick for MS is consistent with how a Great Lakes vessel would be allowed to load in different parts of the navigation season. • Eliminate any choice that is not a standard term you have seen associated with Plimsoll/load line markings in your study materials.