Monday, December 16, 2013

Lift Bridge Boat Signals!

There have been a few questions about the boat and bridge signal horns when the boats are entering and leaving the Port of Duluth.

In most cases, once radio communication with the bridge has been established, use of the boat and bridge sound signals are not necessary and operation of the sound signals is left up to the captains.  Often, boats will not use the loud horns after dark as a courtesy to city residents.

So, most often when you hear the customary horn-blowing sequence  of "long-short-short" it is a friendly salute to the Port of Duluth from the ship captain and is responded to by the lift bridge operator with the same sequence.

While the famous sound may be a courtesy, it has long been part of the nautical tradition of this great inland sea port.

General Navigation Signals
There are also some "Rules of the Sea" for mariners that are used world-wide:  
The law prescribes signals for vessels in sight of each other to indicate the intended course of a vessel when necessary for safe navigation.
One short blast (1 second) of the horn or whistle will show an intention to direct course of vessel to own starboard (right).
Two short blasts will show intention to direct course of vessel to own port (left).
Three short blasts will indicate the vessel's engines are going astern (in reverse).
Five or more short and rapid blasts is a danger signal used when the other vessel's intentions are not understood or where the other vessel's indicated course is dangerous.
Prolonged blast (4 to 6 seconds) will indicate situations of restricted visibility. 


  1. Thanks for the info, Dennis. I love how the Tregurtha has its own rhythm which the bridge echoes. And as for disturbing the citizens after dark? What a way to go!!!!

  2. What are the quiet hours for ships and the bridge? I haven't quite wrapped my brain around it yet.

  3. No set time on quiet hours. Usually 9PM-7AM, but, depends on the time of year. Really up to the captain. I have seen them signal at 11PM when there were lot's of folks on the piers.

  4. I just heard the bridge respond with three long blasts and two short. Is this a special signal for the end of the shipping season?

    1. Thats a common salute. The reply is the same sequence.

    2. I heard this same signal last night, as the Edwin H. Gott was departing Duluth under the Lift Bridge around 7:30pm (Sat Dec 7, 2019). I had just learned earlier that day that the usual signal (1 long, 2 short) is the standard captain's salute, but that 3 long and 2 short is a Master Salute, and not frequently used. So I was wondering the same thing... could this be the Gott's last trip this season? Or perhaps the captain's final trip?

  5. I have been watching and listening to this video on YouTube: Does the Lift Bridge have a light signal that flashes along with their signal horn? And do some ships have a signal light as well?

  6. Does each harbor have its own sequence of whistle blasts?