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Annex III · Technical details of sound signal appliances

COLREGS Annex III · 2 — Bell or gong

(a) Intensity of signal A bell or gong, or other device having similar sound characteristics shall produce a sound pressure level of not less than 110 dB at a distance of 1 metre from it.

(b) Construction Bells and gongs shall be made of corrosion-resistant material and designed to give a clear tone. The diameter of the mouth of the bell shall be not less than 300 mm for vessels of 20 metres or more in length. Where practicable, a power-driven bell striker is recommended to ensure constant force but manual operation shall be possible. The mass of the striker shall be not less than 3 per cent of the mass of the bell.

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All COLREGS Rules and Annexes

Part A · General

Part B · Steering and sailing rules

Part C · Lights and shapes

Part D · Sound and light signals

Part E · Exemptions

Part F · Verification of compliance

Annex I · Positioning and technical details of lights and shapes

Annex II · Additional signals for fishing vessels fishing in close proximity

Annex III · Technical details of sound signal appliances

Annex IV

COLREGS oral exam questions and answers — all 114 examiner-style questions on one page, Rule by Rule, as a drill you mark yourself.

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An independent study aid built by CryoSim from the text of the 1972 Collision Regulations as amended. It is not an IMO publication and is not endorsed by the IMO — for navigation and legal purposes, use the official text.