Athwartships

Athwartships is a nautical term describing a direction across the width of a vessel, perpendicular to the keel and running from port to starboard. In naval terminology it indicates an orientation or alignment that is across the ship’s length, rather than along it. The term can function as an adjective (athwartships bulkhead, athwartships deck) or as an adverb describing movement or position across the beam.

In practice, athwartships elements or lines run crosswise to the vessel’s main axis. Examples include bulkheads, decks, frames, or girders that span the ship’s width. This contrasts with fore-and-aft or longitudinal components that extend along the length of the ship from bow to stern. The concept is often paired with terms like transverse or crosswise to convey a similar sense of crosswise orientation. The idea also applies to forces or motions encountered at sea when a load, wind, or water exerts influence across the vessel rather than along its length. While most common in nautical engineering and ship design, the term is widely understood in maritime contexts.