In the latest instillment of their Good Catch series, warning that emergency alert functions on ship radios can unintentionally interrupt important communications.
An inland towing vessel was pushing nine loaded barges downriver, approaching a fleeting area just below a bridge. The towing vessel was scheduled to drop off six of the barges and pick up five others before continuing further downriver.
The captain anticipated that tying up would be a little tricky that day due to the strong current and an eddy just above the fleeting area.
To mitigate the risks, he had two deckhands on the lead barges and another halfway to the front of the tow so they could quickly tie up and secure the tow. He had explained his plan to the deckhands, and they took handheld radios with them so he could communicate with them on their working channel.
Just as he was making his final approach to the fleeting area, he heard a distress call on Very High Frequency (VHF) channel 16 regarding a fire on another towing vessel upriver from his location. Almost immediately, he was reassured to hear that other nearby vessels and emergency services were responding.
Seconds later, he radioed his deckhands, but they did not acknowledge his call. He could see them and thought it was strange that they did not react. He repeated his call to them, and still, they did not respond.
Thinking quickly, he gave a toot on the horn to alert them, then shifted to the deck loudhailer to direct the deckhands. It was not ideal, but it worked. They reacted quickly and secured the tow without incident, but the captain experienced several tense moments in the process.
The captain was mad at the deckhands for not responding to his radio calls, but they pointed out that no call came over their handheld radios. When they tested them standing in the wheelhouse, they discovered that the VHF radio in the wheelhouse was on channel 16, while the handheld radios remained on the working channel.
They did not know how that happened, but it explained why the deckhands did not receive his calls on their handheld radios.
Actual damage
None, because of the captain’s quick thinking and decision to use the deck loudhailer.
Potential damage
Had the Captain not acted swiftly, and had the deckhands not responded with equal urgency, one or more deckhands could have been injured from a hard impact, barges could have been damaged, and/or barges could have broken loose and drifted downriver, resulting in additional consequences.
Lessons learned
- VHF radio sets are equipped with Digital Selective Calling (DSC) for use in emergencies. When a DSC distress call is activated and goes out, the VHF radio that broadcasts the distress call and all the VHF radios that receive the distress call automatically switch to channel 16. This is, by design, consistent with international standards for marine VHF radios.
- In this near miss incident, the distress call for the vessel on fire caused the radio in the wheelhouse to automatically switch to channel 16 from the working channel it had been set on. The captain did not realize that the radio had automatically switched channels. The handheld radios were not equipped with DSC, so they remained on the working channel. Thus, the Captain’s radio call to the deckhands was actually made on channel 16 instead of the intended working channel and, therefore, was not received by the deckhands.
- VHF radios are required to have a visual indication of automatic switching to channel 16, but if the radio is not readily visible, or the captain is unaware of the need to look for that visual indication, it could easily be missed.
- This “auto switching” feature can be turned off. It is recommended that one of the VHF radios in the wheelhouse has the “auto switching” feature turned off. When that feature is turned off, distress calls will still be received, but the radio will not automatically switch to channel 16.
- Companies should establish a policy for their vessels regarding disabling the “auto switching” feature. They can review guidance from the radio manufacturer regarding the steps to disable “auto switching.”
When you identify a hazard before something goes wrong… it’s a Good Catch.
When you stop an operation before something bad happens… it’s a Good Catch.
When you implement a policy related to turning off the channel 16 “auto switching” function on VHF radios across the fleet… that’s a Good Catch, too!