CFR > Title 33 - Navigation and Navigable Waters > CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY > SUBCHAPTER E—INLAND NAVIGATION RULES (parts 83 to 90) > PART 83—RULES > SUBPART D—Sound and Light Signals (§83.32 to §83.37) > 83.32—Definitions (Rule 32).

83.32—Definitions (Rule 32).

(a) Whistle means any sound signaling appliance capable of producing the prescribed blasts and which complies with specifications in Annex III to these Rules.
(b) Short blast means a blast of about 1 second's duration.
(c) Prolonged blast means a blast of from 4 to 6 second's duration.