Pick four parameters: your vessel, the other vessel, the encounter (head-on / crossing / overtaking), and the visibility. The picker returns the applicable rules and the required action — useful for STCW oral-exam preparation or a quick refresher on watch.
Always cross-check with the full text of the COLREGs and with your ship's own instructions; this is a study aid, not an authority.
Result
Give-way
I am the give-way vessel. Alter course to starboard or reduce speed; do NOT cross ahead.
Applicable rules
Rule 5 — Look-out
Rule 6 — Safe speed
Rule 7 — Risk of collision
Rule 8 — Action to avoid collision
Rule 11 — Application (in sight)
Rule 15 — Crossing situation
Rule 16 — Action by give-way vessel
Notes
· She is on my starboard side; I keep out of her way and avoid crossing ahead.
When to use this tool
Quick answer on watch during a novel encounter — e.g. is the CBD (constrained by draught) vessel the give-way or stand-on when crossing a sailing vessel in restricted vis? Study aid for STCW oral-exam preparation. NOT a substitute for reading the COLREGs directly.
Regulatory basis
COLREGs 1972. Rule 18 (Responsibilities between vessels) sets the master hierarchy: not-under-command, restricted-in-ability-to-manoeuvre, constrained-by-draught, fishing, sailing, and power-driven. Rules 13-17 govern specific encounter geometries. Rule 19 applies in restricted visibility.