BACKGROUND TO THE INVENTION The following description relates to use of the mayday communication systems at sea but is not limited thereto as the mayday communication system can be used in any situation where it is useful.

When people are at sea there is a major problem when they are lost overboard, whether they are part of a small crew or a single sailor on a small vessel such as a yacht, or are crew members on ocean going ships such as freight carriers.

If the person is lost overboard it may be the case that he or she is not known to be missing for a significant time period. If the person overboard is a lone sailor, he or she if lost overboard cannot access any radio system to place a mayday distress call.

In general, radio communication such as voice messages over the radio spectrum is the known way of requesting assistance if distressed while at sea. Therefore access to a radio set is needed to place such a distress call.

As seen above it is not always possible for the person in distress who needs assistance to place a mayday radio call as they cannot always access a radio system. It is believed that there is a need for a mayday communication apparatus to provide a suitable means for activating a mayday distress signal when a person has no access to a radio system.

OBJECT OF THE INVENTION Therefore it is the object of the invention to provide a mayday communication apparatus which substantially overcomes or ameliorates the above mentioned problems. At the very

least the object of the present invention is to provide an alternative to known communication apparatus used to provide mayday distress signals.

DISCLOSURE OF THE INVENTION According to one aspect of the present invention there is provided a communication system comprising at least one base transmitter/receiver located in a device which is either fixed at any particular location or is able to be easily transported in a mobile arrangement; and a plurality of individual transmitters which are able to be worn by people in the form of a wrist device, pendant or the like; wherein each said transmitter sends an encoded signal to said base transmitter/receiver when activated by a person wearing said wrist device, pendant or the like or when automatically activated according to a pre-set protocol; said base transmitter/receiver receiving said encoded signal and thereafter providing an alarm signal indicating the source of said encoded signal, wherein said base transmitter/receiver provides a transmit signal to a location remote from said transmitter/receiver to relay said received encoded signal.

Preferably, said base transmitter/receiver determines the location of the person wearing said wrist device, pendant or the like by directional and distance discrimination means.

According to another aspect of the present invention there is provided a communication system comprising at least one base transmitter/receiver located in a device which is either fixed at any particular location or is able to be easily transported in a mobile arrangement; and a plurality of individual transmitters which are able to be worn by people in the form of a wrist device, pendant or the like; wherein each said transmitter sends a signal to said base transmitter/receiver when activated by a person wearing said wrist device, pendant or the like or when automatically activated according to a pre-set protocol; said base transmitter/receiver receiving said signal and thereafter providing an alarm signal indicating a mayday situation.

BRIEF DESCRIPTION OF THE DRAWINGS One embodiment of the present invention will now be described with reference to the drawings in which: Fig. 1 is a schematic block diagram of a communication apparatus of a preferred embodiment.

BEST MODE OF CARRYING OUT THE INVENTION A communication system 10 is illustrated in the drawing and in the preferred form is used as a mayday communication apparatus. The communication system 10 has a base station 11 which has a radio wave transmitter 12 and a receiver 13. The base station 11 communicates with a number of individual transmitters 14 which are able to be worn by people in the form of a wrist device, pendant or the like. The number of individual transmitters 14 are in radio communication with the base station 11.

The base station 11 in one form is preferably a fixed base station, while in another form can be in a mobile pack or the like. The base station 11 is preferably powered by a battery power source which if it is in a mobile pack, is rechargeable. The individual transmitters 14 also have a battery power supply and are preferably in water proof containers as they are worn by people at sea who would be in the water in a rescue situation.

The individual transmitters 14 are manually activated by the person wearing them and as such they have a failsafe press button (not illustrated) which is covered to prevent inadvertent activation thereof.

When in use, the system 10 works by the activation of one or more of the individual transmitters 14. Naturally if more than one of the individual transmitters 14 are activated at any one period of time, the base station will receive the distress signals received therefrom. In the preferred form of the invention, the distress signals from the individual transmitters 14 are encoded with their own individual code and the base station discriminates the different codes and thereby determines which of the individual

transmitters 14 has been activated. Naturally, it is also within the scope of the present invention that the distress signals are not encoded individually and therefore the base station receives one or more distress signals and cannot discriminate amongst them. This is the particular case where most people can be accounted for by sight and it is not necessary to have the discriminating feature. This can occur at sea when the boat is relatively small and therefore the crew is few in numbers.

Also in the preferred form of the invention, the base station 11 determines the direction and distance of the received distress signal, however this is merely a preferred optional feature.

The base station 11 provides an alarm either at the base station 11 or at a location remote from the base station 11 when a distress signal is received. The local alarm can take the form of audible and visible stimuli such as a strobe light The remote alarm can be sent by the base station via a radio link or telephone landline to a centralised rescue centre. This remote alarm can take the form of a recorded message or be simply an activated alarm signal in the form of a flashing light.

The foregoing describes only some embodiments of the present invention, and modifications obvious to those skilled in the art can be made thereto without departing from the scope of the present invention.