Not many people are going to read all the way through this Annex. Anyone who does must be really keen!
Essentially this Annex sets the technical standards for equipment, and is more relevant to ship builders and equipment designers.
There are a couple of useful points:
(i) The larger the vessel, the deeper the pitch of the sound signals.
This is a means of differentiating between the various vessels which sound one prolonged followed by two short blasts in reduced visibility.
(ii) The larger the vessel the further away it can be heard.
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