Glossary of nautical terms (A-L) in the context of "Seamanship"

In general, an imaginary line is usually any sort of geometric line (more generally, curves) that has only an abstract definition and does not physically exist. They are often used to properly identify places on a map.

Some outside geography do exist. A centerline is a nautical term for a line down the center of a vessel lengthwise.

Maine was a United States Navy ship that sank in Havana Harbor on 15 February 1898, contributing to the outbreak of the Spanish–American War in April. U.S. newspapers, engaging in yellow journalism to boost circulation, claimed that the Spanish were responsible for the ship's destruction. The phrase, "Remember the Maine! To hell with Spain!" became a rallying cry for action. Although the Maine explosion was not a direct cause, it served as a catalyst that accelerated the events leading up to the war.

Maine is described as an armored cruiser or second-class battleship, depending on the source. Ordered in 1886, she was the first U.S. Navy ship to be named after the state of Maine. Maine and its contemporary the battleship Texas were both represented as an advance in American warship design, reflecting the latest European naval developments. Both ships had two-gun turrets staggered en échelon, and full sailing masts were omitted due to the increased reliability of steam engines. Due to a protracted 9-year construction period, Maine and Texas were obsolete by the time of completion. Far more advanced vessels were either in service or nearing completion that year.

On a vessel's hull, a rib is a lateral structural member which runs between gunwales and sprouts from the keel. They are called "ribs" because they resemble the human rib. The ship's outer planking and inner sheathing are attached to the ribs. For ships that are too large for a rib to be made out of a single piece of wood, the ribs are made of multiple sections called futtocks that are scarfed together. The ancient writers Polybius and Plato held that, since the ribs of a ship were the most important part of the ship's framework, then if the ribs were new, then the ship as a whole was new. Iron was first used in shipbuilding to make the ribs and frames, with wood sheathing attached to them, but this proved inadequate compared to replacing the wood sheathing with iron plates.