AutoHoot & COLREGs


Fog Horn


Use AutoHoot to provide fog horn signals in accordance with COLREGs.

AutoHoot helps to ensure that you make sound signals in accordance with Colregs guidelines you will find the full guidelines in Section D of the IRPCS, entitled Sound and Light Signals.

There are two categories where specific signals are defined: Manoeuvring and Warning Signals, and Restricted Visibility (Fog) Signals.

Manoeuvring and Warning Signals (RULE 34)

You can pre-set AutoHoot with the following sound signals, note "Short blast" means about a second.

One short blast I am altering my course to starboard
Two short blasts I am altering my course to port
Three short blasts I am operating astern propulsion (i.e. slowing down, stopping and/or going in reverse)
Five short blasts I am unsure of your intention, or I am unsure you are taking sufficient action to avoid collision: diplomatic language for Get Out Of The Way.


If Intending To Overtake A Vessel In A Narrow Channel

Two long blasts and one short blast I intend to overtake you on your starboard side
Two long blasts and two short blasts I intend to overtake you on your port side
One long, one short, one long, one short If you are responding and agree to be overtaken
One prolonged blast (four to six seconds) is used by vessels in narrow channels coming up to a bend or obstruction. It is answered by the same signal from another vessel coming the other way.
Sound Signals in Restricted Visibility (RULE 35) There is a list of these, reflecting the need to identify to other vessels what kind of vessel you are. Most of them are repeated every two minutes or so.
One prolonged blast power-driven vessel making way
Two prolonged blasts power-driven vessel stopped (but not anchored)
One prolonged and two short blasts not under command, restricted in ability to manoeuvre (including when anchored), constrained by draught, sailing vessel, engaged in fishing (including when anchored), engaged in towing or pushing. In other words, everything that a power-driven vessel has to give way to.
One prolonged and three short blasts the vessel being towed. Ideally this signal is made immediately after the towing vessel's signal.
One short, one prolonged and one short blasts vessel at anchor to warn an approaching vessel.
Four short blasts pilot vessel engaged on pilotage duty.

Skippers need to know what sounds they are required to make. When underway, a motor boat (or yacht motoring) gives a prolonged blast every two minutes. When sailing, one long and two short.

Vessels less than 12m are not obliged to make these signals but should make some other sound every two minutes.

At anchor, vessels less than 20m should as a minimum make some sound every two minutes.

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