Part CBasic
Rule 31: Seaplanes
Seaplanes and WIG craft must show the closest practicable equivalent to prescribed lights/shapes.
Detailed Explanation
If exact compliance is impracticable for a seaplane or WIG craft, it shall exhibit lights/shapes as closely similar in characteristics and position as possible. The principle is equivalence, not exemption.
Key Points
- Seaplanes must comply as closely as practicable
- Aim for closest conformity with light/shape rules
- Same principle extends to WIG craft and ekranoplans
Examples
- A seaplane taxiing on the water at night shows navigation lights as close to Rule 23 requirements as its design allows. Per Rule 31, exact conformity is not required if structurally impracticable.
- A WIG craft operating on the surface displays lights per COLREG. When it lifts off, it transitions to ICAO aviation rules, but while surface-bound it follows Rule 31 provisions for seaplanes.
Common Mistakes
- Expecting seaplanes to show exactly the same light configuration as conventional vessels when their structure makes it impracticable.
- Ignoring seaplanes or WIG craft entirely when assessing collision risk because they are not 'normal vessels'.