Athwartships describes anything oriented across a vessel’s width — running from port to starboard (side to side) — as opposed to fore-and-aft, which runs along the ship’s length.
Common Uses
- Structural members — transverse frames and bulkheads run athwartships, as distinct from longitudinal members (girders, stringers) which run fore-and-aft
- Cargo stowage — containers or cargo can be stowed “athwartships” (across the ship’s width) versus “fore-and-aft” (along its length), a real, practical distinction affecting stability and space utilization
- Ship motion — forces or accelerations described as athwartships act side-to-side, relevant to cargo securing calculations
Athwartships vs Transverse
These terms are largely interchangeable in practice — “athwartships” is the more traditionally nautical term, while “transverse” is used more in technical/engineering contexts (transverse bulkhead, transverse framing), though both describe the same side-to-side orientation.
Why the Distinction From Fore-and-Aft Matters
A vessel’s structural strength, stability, and cargo securing requirements are calculated differently for athwartships versus fore-and-aft forces — confusing the two orientations in a stability or securing calculation would produce a meaningfully wrong result, not just an imprecise one.
Exam Relevance
Athwartships as a structural and directional term, and its distinction from fore-and-aft orientation, is covered within Ship Construction and Cargo Work topics in deck officer competency exams.