Mixed Signals?

Hi, I’m John Lange, an electrician for the North Carolina Department of Transportation. I am responsible for maintaining three of the state’s most critical drawbridges—or at least I was when I wrote this. Who knows what future-me is up to now?

In an era where VHF radios and cell phones dominate maritime communications, the traditional sound signals referenced in 33 CFR § 117.15 present an interesting paradox. While the regulation’s original context no longer perfectly aligns with modern operations, its underlying safety principle remains more vital than ever – though perhaps for reasons different than originally intended.

A close reading of 33 CFR § 117.15 reveals language that, in many ways, no longer matches current operational realities. Written in an era when sound signals were the primary means of communication, the regulation describes a complex system of signals that assumed minimal radio communication. Today, with approximately 99% of bridge-vessel communications occurring via VHF radio or phone, the literal interpretation of these regulations can create more confusion than clarity.

However, the core purpose – ensuring safe bridge operations – remains crucial.

While some bridge owners have modified sound signals in various ways, creating potential confusion, the safest approach is to maintain a simplified but standardized system that honors both the regulation’s intent and modern operational needs:

• One long blast followed by one short blast immediately before opening
• Five short blasts immediately before closing

This streamlined approach maintains compliance while providing clear, unambiguous signals that serve their most critical modern purpose: warning vessels that are in communication with a drawbridge as well as those that might be unknown or unseen to the bridge operator.

Consider this real-world incident: On a dark and moonless night at 3 AM, I was a bridge operator preparing to close my span after a tug boat passed through. Despite seeing nothing in either direction, even after careful visual inspection, the standard five short blasts prompted an urgent radio call from the tug: “Whoa, you’re not closing the bridge, are you?”

What I couldn’t see was a massive sea-going tug and barge combination, painted entirely black, so large that its running lights were obscured from the bridge tower’s view. Without that required sound signal, the bridge would have closed on a vessel that I never suspected was there, potentially causing catastrophic damage.

This incident highlights why sound signals remain irreplaceable, regardless of how the regulation’s original language may read today. They serve as:

• A universal safety check that transcends electronic communication
• An alert system for vessels that may have radio failures
• A warning mechanism for small craft that might not be monitoring marine channels
• An additional layer of safety in poor visibility conditions

Rather than viewing sound signals as outdated or strictly regulatory requirements, we should recognize them as a critical safety system that serves a purpose distinct from modern communication methods. They provide an essential layer of protection specifically for vessels that bridge operators might not know are present – a scenario that radio and phone communications cannot address.

While the literal interpretation of 33 CFR § 117.15 may need updating to reflect current operational realities, the fundamental safety principle behind sound signals remains as crucial as ever. The standardized use of one long and one short blast before opening, and five short blasts before closing, provides a clear, universal warning system that serves its most vital modern purpose: protecting vessels that might otherwise go unnoticed.

In an environment where split-second decisions can mean the difference between safe passage and disaster, these sound signals represent more than just regulatory compliance – they represent an irreplaceable safety measure that protects against the unknown and unseen. The question isn’t whether to maintain sound signals, but rather how to standardize their use to maximize their safety benefits in today’s maritime environment.