Sound signals — listen and identify
Tap Play to hear a randomly-chosen sound signal from COLREG Rules 34 and 35. Choose what you think it means; the answer reveals on selection. Use this for STCW oral-exam preparation or for keeping rusty knowledge sharp on long passages.
Audio is generated in the browser (low-pitched horn tone). Short blast (•) ≈ 1 s. Prolonged blast (—) ≈ 4–6 s. See the full sound-signals reference for the underlying material.
When to use this tool
STCW oral-exam preparation, bridge-team drill preparation for restricted-visibility scenarios, keeping recognition sharp on long passages, refresher after long shore leave.
Regulatory basis
COLREGs Rule 34 (manoeuvring + warning signals) + Rule 35 (sound signals in restricted visibility) + Rule 36 (attracting attention) + Annex III (technical details of sound signal appliances). Whistle + bell + gong requirements per vessel size.