WO1984004836A1

WO1984004836A1 - An anchoring alarm, especially for leisure boats

Info

Publication number: WO1984004836A1
Application number: PCT/SE1984/000203
Authority: WO
Inventors: Mickey Behrendtz
Original assignee: Nordic Intertrade Ab
Priority date: 1983-05-26
Filing date: 1984-05-28
Publication date: 1984-12-06
Also published as: EP0179060A1; AU3017184A; SE8302968D0; SE432315B

Abstract

When anchoring such boats by means of an anchor and a line attached to the bow of the boat it is desirable to receive an alarm which is initiated dependent upon the movement of the boat round with the wind direction when the wind conditions change to such an extent that it is necessary to anchor up anew. This object is achieved in that the anchoring alarm comprises a first device (1) for monitoring the wind speed and for producing a first signal when the wind speed exceeds a predetermined value, and a second device (2) for monitoring the value of the angle between the lengthways direction of the boat and a reference direction, this angle being set equal to nil at the time of anchoring, and for producing a second signal when the value of the angle exceeds a predetermined value as a result of a change in wind direction. The anchoring alarm also comprises an alarm arrangement (5) connected signalwise with the said devices and designed to produced a noise and/or light signal when the said first and second signals occur simultaneously.

Description

An Anchoring Alarm, especially for Leisure Boats

The present invention relates to an anchoring alarm, especially for leisure boats.

For various reasons it may be necessary or preferable to moor the boat by means of an anchor and a line attached to the bows, which in everyday terms is known as letting the boat ride at anchor. When thus moored the lengthways direction of the boat swings round in the wind direction. An anchor is usually designed so that the force with which the anchor can be loaded withδut losing its hold is greatest in one specific direction and therefore when anchoring the aim is to make this direction coincide with the wind direction. Assuming that the anchor has sufficient holding strength and the wind conditions remain constant, it is not disadvantageous to let the boat ride at anchor.

However, if the wind conditions should alter so that the strength and the direction of the wind are changed the anchor may lose its hold and the boat may start to drift, which can have serious consequences resulting in damage to the boat and/or the crew. So as to avoid the risk of such damage, it is necessary, at least during unsettled weather, to stand watch at night so as to be able to anchor up again in good time if a tendency to drag the anchor should become apparent. Naturally, this is inconvenient.

The object of the present invention is to provide an anchoring alarm, especially for leisure boats, by means of which, when wind conditions change to the extent that there is a danger that the boat will break loose from its mooring and start to drift, an alarm signal is produced to warn in good time that re-anchoring may be necessary. According to the invention this is achieved in that the anchoring alarm comprises a first device for monitoring the wind speed and for producing a first signal when the wind speed exceeds a predetermined value, a second device for monitoring the value of the angle between the lengthways direction of the boat and a reference direction, this angle being set equal to nil at the time of anchoring, and for producing a second signal when the angle value exceeds a predetermined value as a result of a change in wind direction, and an alarm arrangement connected signalwise with the said devices and designed to produce a noise and/or light signal when the said first and second signals occur simultaneously. The invention will be explained further in the following with reference to the accompanying drawing, on which Figures 1a and 1b show schematically an embodiment of the invention with the wind conditions generally unchanged from those prevailing at the time of anchoring (Figure 1a) and with the wind conditions changed so much that the boat should be anchored afresh. An alternative embodiment of the invention is shown schematically in Figure 2. An anchoring alarm according to the present invention comprises a first device 1 for producing a first signal when the wind speed and thus also the wind pressure exceed a predetermined value, a second device 2 designed to produce a second signal when the wind shifts through an angle which exceeds a certain angular value, and an alarm arrangement 5 connected signalwise with the said devices 1, 2 via lines 3, 4, with the task of producing a noise and/or light signal when the said first and second signals occur simultaneously. As shown schematically in Figure 1, the first device 1 may consist of a conventional wind pressure gauge 6 with a chamber 7 open to the front and a piston 8 which is movable therein, and an optical monitoring device 9 with a light source, such as a photodiode, and a photocell 9b. At low wind pressure values the piston 8 is located well back in the chamber 7 and a plate 10 effectively connected to the piston interrupts the path of the beam between the light source 9a and the photocell 9b, the output signal then being equal to nil. With increasing wind pressure the piston 8 is forced outwards towards the opening of the chamber and at a certain wind pressure level the path of the beam is no longer interrupted by the plate 10, so that as a result an output signal equal to the above-mentioned first signal is obtained by the photocell 9b. This is transmitted via the line 3 to the alarm arrangement 5.

The second device 2 comprises a rotatably mounted sector-shaped plate 11 which is effectively connected to a compass needle 12 indicated on the drawing by an arrow, and an. optical monitoring device 13 of the same kind as the monitoring device 9, i.e. comprising a light source and a photocell the latter being' connected via the line 4 to the alarm arrangement 5. The sector-shaped plate has a sector angle 14 within which it interrupts the path of the beam between the light source and the photocell. Within the remainder of the sectorshaped plate 11 the said beam path is not interrupted but, as before, an output signal equal to the second signal is produced here. The sector angle 14 is equal to double the wind shift angle which the anchor can tolerate without losing hold.

At the time of anchoring, the monitoring device 13 is rotated into a position wherein it divides the sector angle 14 in half. The compass needle 12 holds the sectorshaped plate 11 in a position which varies only dependent upon the movements of the boat swinging round in the direction of the wind (see Figure 1a). If the wind direction now changes by more than half the sector angle 14 (see Figure lb) then, as a result of the boat striving to lie with the wind direction, the sector-shaped plate 11 no longer interrupts the path of the beam and the second signal is obtained as described above. The alarm arrangement 5 is designed to produce a noise and/or light signal when the signals arrive simultaneously via the lines 3 and 4. The noise signal can be transmitted over a loud-speaker 15 positioned at a suitable point on the boat, as shown on the drawing.

Obviously, the invention may be constructed in many ways within the framework of the concept of the invention. For example, as shown in Figure 2, the first device 1 may consist of a conventional wind gauge 6 combined with a signal level monitoring circuit, a so-called level balancer circuit, expediently positioned in the alarm arrangement 5.

Claims

P a t e n t C l a i m s

1. An anchoring alarm, especially for leisure boats, characterised in that the anchoring alarm comprises a first device (1) for monitoring the wind speed and for producing a first signal when the wind speed exceeds a predetermined value, a second device (2) for monitoring the value of the angle between the lengthways direction of the boat and a reference direction, this angle being set equal to nil at the time of anchoring, and for producing a second signal when the angle value exceeds a predetermined value as a result of a change in wind direction, and an alarm arrangement (5) connected signalwise with the said devices and designed to produce a noise and/or light signal when the said first and second signals occur simultaneously.

2. An anchoring alarm according to Patent Claim 1, characterised in that the said second device comprises a sector-shaped plate (11) with a sector angle (14) within which the plate (11) is closed off and which is equal to double the said predetermined angle value, an optical monitoring device (13) with a light source and a photocell arranged on either side of the sector-shaped plate (11) and designed to produce the second signal when the path of the beam between the light source and the photocell is no longer interrupted by the sector-shaped plate (11), and a compass (12) effectively connected to the monitoring device, for setting the sector-shaped plate (11) and the monitoring device (13) relative to each other at the time of anchoring, with reference to the lengthways direction of the boat and the said reference direction.