A schooner has at least two of them

MASTS

Think of the tall vertical structures that hold up a ship's sails; a schooner relies on multiple to catch the wind efficiently.

A schooner is a type of sailboat, and the clue hints at a key feature it must have—specifically, the vertical poles that hold its sails. The word "masts" fits because a schooner always has at least two of them to support its rigging. The answer plays on nautical terminology, where "masts" are essential for any multi-sail vessel like a schooner.