SPCC NOTES ON VISITING THE RIVER THAMES
HORN SIGNALS
The term Short Blast means a blast of about 1 second duration The term Long Blast means a blast of about 4–5 seconds duration
SIGNAL MEANING
1 short blast I am altering my course to starboard (RIGHT)
2 short blasts I am altering my course to port (LEFT)
3 short blasts My engines are going astern
5 or more short blasts You are not taking sufficient action to avoid me; or I do not understand your intentions or actions
4 short blasts followed by 1 short blast I am turning round with my head (BOW) swinging to starboard (RIGHT)
4 short blasts followed by 2 short blasts I am turning round with my head (BOW) swinging to port (LEFT)
1 prolonged blast I am about to get underway, i.e. depart from moorings, jetty or dock entrance
2 long blasts followed by 1 short blast I am about to overtake on your starboard (RIGHT) side
The reply by the vessel being overtaken indicating readiness to be overtaken is 1 long blast, 1 short blast, 1 long blast and 1 short blast
2 long blasts followed by 2 short blasts I am about to overtake on your port (LEFT) side
The reply by the vessel being overtaken indicating readiness to be overtaken is 1 long blast, 1 short blast, 1 long blast and 1 short blast
SAFETY
Anyone navigating a vessel without due care and attention, or in such a manner as to cause damage to other vessels or property or cause injury to persons is guilty of an offence under the Port of London rules and conditions
These signals are made by power driven vessels to indicate their own intended actions to other vessels. However with the ever increasing use of VHF R/T by all classes of vessels, especially by commercial craft, there is less likelihood of sound signals being used. The PLA does not encourage this practice. While small craft should therefore be extra careful and aware of this malpractice, it is strongly urged that smaller craft use sound signals.