09/15/2026
Good review. 🏴☠️
Day shapes are an important part of COLREGS because they help identify what a vessel is doing during daylight. This infographic covers the main shapes for vessels at anchor, under sail and power, towing, fishing, not under command, mine clearance, restricted in ability to manoeuvre and constrained by draught.
It also includes the commonly seen combinations for RAM vessels, dredging and diving operations, towing vessels, pilot vessels, vessels aground, fishing and trawling vessels, sailing yachts and small dive boats. Learning these shapes makes it much easier to understand a vessel’s situation before you even look at its lights at night.
For cadets and beginners, the easiest approach is to first remember the eight basic shapes and then learn the special combinations one by one. Once these patterns become familiar, identifying vessels at sea becomes much quicker and more confident.
Save this post for your navigation revision and share it with someone preparing for a deck or nautical exam.