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The catalogue of lights and shapes

Thirty-four configurations: what is visible at night from each aspect and which day shapes go with it.

The catalogue

Lights and shapes: filters and configurations

“Learning → Lights and shapes”. The chips at the top narrow the list: engine, sail, fishing, special cases. Each card carries a short line about what the vessel is doing.

A configuration card

Aspects, day shapes and the rule

Inside is a night scene and an aspect switch: bow, port, starboard, stern. That is the main thing: from astern a tug and a trawler look nothing like they do from ahead, and the aspect is exactly where people get it wrong.

Below are the day shapes (ball, cone point up or down, diamond, cylinder, two cones apex to apex, basket) and the number of the rule that prescribes these lights. The buttons lead to the text of the rule, to the trainer and to the “Who gives way” builder.

How to read lights

At night a vessel is only visible by its lights: check the colour and the relative position, not the brightness. Green is starboard, red is port, white masthead lights in line tell you the length and the heading, and extra coloured ones tell you what the vessel is doing.

Read next

The lights trainerFifteen night situations in a row: what vessel is that and who gives way. The aspect is part of the question.The COLREGsThe full text of all forty-one rules, a search by situation and a plain-language retelling. All of it works offline.Who gives wayA situation builder: pick your vessel, the other one and how they are placed — and get the answer with a link to the rule.