Forward of the beam describes any bearing falling between dead ahead and abeam (directly to the side) — covering the front quarter-sectors on either side of a vessel.
The Bearing Range
- Dead ahead — 000° relative
- Forward of the beam — anywhere between dead ahead and abeam (000°-090° or 000°-270° relative)
- Abeam — 090° (starboard) or 270° (port) relative
Why This Range Matters
This range directly defines part of a vessel’s navigation light visibility arcs under COLREGs — sidelights (red to port, green to starboard) are visible specifically from dead ahead to abeam on their respective side. Correctly judging whether another vessel is forward of your beam is part of correctly interpreting what lights you should be able to see, and therefore the other vessel’s likely heading and aspect.
Forward of the Beam vs Aft of the Beam
Together with “abeam” as the dividing line, these two terms split a vessel’s side sectors:
- Forward of the beam — between dead ahead and abeam
- Aft of the beam (or “abaft the beam”) — between abeam and dead astern
Exam Relevance
Forward of the beam, its bearing range, and its role in navigation light arc interpretation are core Navigation and COLREGs topics in deck officer competency exams.