---
kind: "section"
citation: "33 C.F.R. § 401.51"
title: "33"
number: "401.51"
heading: "Signaling approach to a bridge."
url: "https://uscodex.org/cfr/33/401.51"
---

# §401.51. Signaling approach to a bridge.

- (a) Unless a vessel's approach has been recognized by a flashing signal, the master shall signal the vessel's presence to the bridge operator by VHF radio when it comes abreast of any of the bridge whistle signs.
- (b) The signs referred to in [paragraph (a)](#a) of this section are placed at distances varying between 550 m and 2990 m upstream and downstream from moveable bridges at sites other than lock sites.

## Notes

### Amendments

[48 FR 20691, May 9, 1983, as amended at 49 FR 30936, Aug. 2, 1984; 73 FR 9954, Feb. 25, 2008; 76 FR 13089, Mar. 10, 2011]

### Authority

Authority: 33 U.S.C. 983(a) and 984(a)(4), as amended; 49 CFR 1.101, unless otherwise noted.

### Source

Source: 39 FR 10900, Mar. 22, 1974, unless otherwise noted.

### Amendments

[48 FR 20691, May 9, 1983, as amended at 49 FR 30936, Aug. 2, 1984; 73 FR 9954, Feb. 25, 2008; 76 FR 13089, Mar. 10, 2011]