Visual Aids to Navigation

• Use charted position, structure, colour, rhythm and surrounding evidence to identify an aid without treating one sighting as an exact fix.
• Distinguish fixed, flashing, isophase, occulting, quick and grouped rhythms by timing one complete repeating period.
• Decode character, colour, period, elevation and nominal range and explain why the printed range is not a promise of detection.

A self-guided revision companion that explains essential concepts, then helps you practise and test them. It supports—but does not replace—recognised instruction, practical training, assessment or certification. Access is a one-time payment, not a subscription.