Boats under 12 metres without a fitted sound-signalling appliance must carry a sound-signalling device. This can be a pealess whistle, a compressed gas horn or an electric horn. Foghorns and/or compressed air horns are very loud and easy to operate. At the push of a button, a sound signal is produced that can be heard up to a mile away. They come in a variety of sizes and some, those that are air activated and recharged through a bicycle type pump, are even environmentally friendly. If this is the type of sound signalling device your vessel is equipped with, be sure that the pump is always at hand in case you need to use this type of horn.
In addition to any type of horn, it is recommended that a pea less whistle be attached to each PFD/Lifejacket on board, no matter the size of the vessel. This ensures that there is a sound signalling device for each person on board in case of an emergency.