International Regulations for Prevention Collisions at Sea PART D
Part DSound and light signalsRule 32. DEFINITIONS a. The word "whistle" means any sound signaling device that can produce the prescribed sounds and meets the technical requirements listed in Appendix 3 to these Rules. b. The term "short sound" means a sound lasting approximately 1 second. c. The term "sustained sound" means a sound lasting 4 to 6...