GB2243476A

GB2243476A - Anti-theft device for water craft

Info

Publication number: GB2243476A
Application number: GB9009387A
Authority: GB
Inventors: David Leonid Kramarenko
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-04-26
Filing date: 1990-04-26
Publication date: 1991-10-30
Also published as: GB9009387D0

Abstract

The device comprises a low output radio transmitter 10 mounted securely to the side of a dock, mooring pontoon, or incorporated in a mooring buoy or place of craft keeping. A receiver 13 with circuitry able to detect the strength of the received signal from the transmitter is connected to an alarm module onboard the craft. When the craft and receiver are moved beyond a certain distance from the transmitter, the signal received at the receiver falls below a preset level, the alarm module onboard the craft sounds the alarm 16. The receiver and alarm can be activated and deactivated by a key switch located on the craft. The receiver, alarm and transmitter can be powered from external sources or from rechargeable batteries, charged by solar cells. <IMAGE>

Description

ASsTTI-THEFT DEVICE FOR WATER CRAFT This invention relates to a anti-theft device for water craft.

Anti-theft devices for water craft are well known, and work along the principles that any forced entry into a craft sets off an alarm.

However, increasingly theft involves the removal of the entire craft from its moorings or place of keeping. The device outlined in this application monitors the position of the craft to its moorings or position of keeping. when the craft is removed a certain distance from its moorings or position of keeping an alarm sounds. Further more the device outlined in this application does not prevent forced entry into the craft.

According to the present invention there is provided a anti-theft device for water craft comprising of a low output radio transmitter, which is mounted on a fixed position relative to the craft. This position might be the side of a dock, mooring pontoon, or incorporated into a mooring buoy. A radio receiver working on the same frequency as the transmitter is mounted on some convenient part of the craft. The receiver has circuitry sensitive to the strength of the received signal. When the craft is removed beyond a certain distance from the transmitter, the signal strength detected by the receiver falls below a preset value, and a alarm located on the marine craft will sound.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a block diagram of the transmitter and receiver modules in the non-alarm state.

Figure 2 shows a block diagram of the transmitter and receiver in an alarm state.

Figure 3 shows the practical installation of the transmitter and receiver in the non-alarm state.

Figure 4 shows the practical installation of the transmitter and receiver in an alarm state.

Figure 5 shows ways of supplying electrical power to the transmitter and receiver.

Figure 6 shows ways of using solar power to recharge the internal batteries of both the transmitter and receiver.

Figure 7 shows an alternate way of mounting the radio transmitter.

Referring to the block diagram in figure 1, the anti-theft device for water craft comprises of a low output radio transmitter 10 mounted in a sturdy weatherproof casing with an external antenna 11. Electrical power for the transmitter either comes from an external source 20 (as in figure 5), or from internal rechargable batteries, recharged by a solar panel 21 ( as in figure 6).

The radio receiver consists of an external antenna 12 (as in figure 1), a receiver module 13 (as in figure 1), a signal level detection module 14 (as in figure 1) and a alarm module 15 (as in figure 1). The modules 13, 14 and 15 are contained on one circuit board, and are mounted in a sturdy weather-proof enclosure inside of the water craft 18 (as in figure 3). The radio receiver obtains its electrical power from the crafts main power supply 19 (as in flgure 5) or from internal rechargable batteries, recharged by a solar panel 22 (as in figure 6).

When the water craft is moored correctly or is in its place of keeping, and the distance from the transmitter antenna 11 to the receiving antenna 12 is no greater than the distance D1 (as in figure 1 and Figure 3) no alarm will sound. Once the craft and receiver is removed from the moorings or place of keeping a distance greater than D1, i.e. to distance D2 (as in figure 2 and Figure 4). The strength of the radio signal as detected by the receiver 13 and signal detection module 14 will fall below a preset value and the alarm module 15 will activate the alarm signal or bell 16 (as in figure 4).

Figure 7 shows an alternate way of mounting the transmitter 10, antenna 11 and solar cells 21 in a floating mooring buoy 23.

The acti;rating and deactivating of the receiver 13 and modules 14 and 15 can be achieved by an external key switch located somewhere on the craft.

In order to provide the best security, both the transmitter 10 and receiver 13 should be matched pairs, working on the same frequency, several different frequency pairs should be available.

CLAIMS 1 A anti-theft device for water craft comprising of a low output radio transmitter, mounted securely to the side of a dock, mooring pontoon, mooring buoy or place of keeping the craft. A receiver with circuitry able to detect the strength of the received signal and connected to an alarm module. This receiver is mounted on the craft in a convenient position. When the craft and receiver are moved beyond a certain distance beyond the transmitter to a point where the signal strength at the receiver falls below a certain preset level the alarm module onboard the craft sounds an alarm.

2 A anti-theft device for water craft as claimed in claim 1 wherein the electrical power for the transmitter is supplied by an external power source or be rechargable internal batteries, charged from solar cells.

3 A anti-theft device for water craft as claimed in claim 1 where the electrical power for the receiver and alarm circuits is obtained from the crafts internal electrical power supply, or form rechargable batteries powered from solar cells.

4 A anti-theft device for water craft as claimed in claim 1 where different matched frequencies are available for different pairs of receivers and transmitters.

5 A anti-theft device for water craft as claimed in claim 3 where the receiver and associated modules are activated and deactivated by a remote key switch located in a convenient position on the craft.

Claims

6 A anti-theft device for water craft substantially as described herein with reference to Figures 1-6 of the accompanying drawings.