US2810120A

US2810120A - Anchor alarm device

Info

Publication number: US2810120A
Application number: US550592A
Authority: US
Inventors: Thomas R Parker
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-12-02
Filing date: 1955-12-02
Publication date: 1957-10-15
Anticipated expiration: 1974-10-15

Description

Oct. 15, 1957 T. R. PARKER 2,810,120

ANCHOR ALARM DEVICE Filed Dec. 2, 1955 Y 2 Sheets-Sheet 1 HTTORI EY$ United States Patent ANCHOR ALARM DEVICE Thomas R. Parker, Durham, N. C.

Application December 2, 1955, Serial No. 550,592

6 Claims. (Cl. 340-29) My invention relates to a drift alarm device for marine vessels and the principal object is to provide a device which will give audible or visual warning that an anchored vessel is dragging its anchor or drifting from its anchored position but will not give such warning if the vessel is only moving about its anchorage circle when the anchor is holding.

The device is particularly useful for small craft such as boats, barges, seaplanes and the like (which I refer to herein as vessels) on which it is not usual to keep a night watch. When such vessels are anchored it is not infrequent that high wind, current conditions, fouling of the anchor by the anchor line, etc. will cause the anchor to lose its hold on the bottom and the vessel will drift in the direction of the wind or current. When this occurs the anchor will drag and the dragging anchor will tend to hold the bow of the vessel into the wind or current as the boat drifts. It is drifting of this charac ter which will activate the drift alarm device.

An anchored vessel will also move in an approximate circle about its anchor when the anchor is holding, due to changes in current, tide and wind condition and it is a feature of my alarm device that such normal movement of the vessel can take place without activation of the alarm.

I have illustrated my invention in preferred form in the accompanying drawings wherein:

Fig. 1 shows in full lines a vessel at anchor with my alarm device mounted on the bow. In dotted line the vessel is shown dragging its anchor.

Fig. 2 illustrates in full lines the vessel at anchor with the anchor holding and in dotted lines shows the vessel as it has moved about its anchorage circle.

Fig. 3 illustrates in dotted lines the vessel at anchor and in full lines the position of the vessel after it has dragged its anchor.

Fig. 4 is a sectional elevation of the alarm and alarm actuating and mounting mechanism.

Fig. 5 is a plan view of Fig. 4.

Fig. 6 is a section taken on the line 66 of Fig. 4.

Fig. 7 is a diagram of the electrical circuit of the alarm.

Referring now to Figures 4 to 7 the alarm device is mounted in a rectangular box B which is attached to the bow of the vessel A by means of screws or bolts extending through apertures 8. The cover of the box is readily removable to permit inspection and adjustment of the alarm.

The alarm comprises a rustless tubular member 9 extending through the forward end of the box and pro jecting over the bow of the vessel. The tube 9 is mounted on the base of the box B by means of a clamp 10 adjacent the forward wall of the box. The clamp has a longitudinal bore 11 extending at an angle to the horizontal and the tube 9 is secured in this bore of the clamp by means of set screw 12. The rear end of the tube is supported by a brace 13 which is secured to the bottom of the box and it will be observed that the tube 9 has a slight downward inclination from rear to front.

A solid rustless metal rod 14 is slidably mounted in the tube 9 and extends beyond the ends of the tube both at the forward and rear ends thereof. Rearward movement of the rod 14 is limited by engagement of the pin 15 with the forward end of the tube 9.

A spring 16 is attached to the rear end of the rod 9 and the rear end of the spring 16 is attached to a movable cross-bar 17 carried by screws 18. Springs 19 surrounding screw members 18 bear against the cross-bar 17 and the rear end of the box B and urge the cross-bar forward and the position of the cross-bar can be adjusted forwardly and rearwardly by means of the screws 18 in order to adjust the tension of the spring 16.

A metallic collar member 20 is secured to the rear end of the rod 14 by means of a set screw and this collar member is electrically connected by means of a wire 21 to a terminal member 22 extending through the wall of the box 8.. Wire 23 is connected at one end to the terminal 22 and at the other end to the terminal of an electrical bell or light indicated as a whole by the reference character C. A tubular insulating sleeve 24 is mounted on the rear end of the tube 9 and to this sleeve an electrical contact member 25 is secured by means of screws, one of the screws constituting an electrical terminal. This latter terminal is connected to one side of a switch D by means of a wire 26 and the other side of the switch is connected by wire 27 to terminal member 28 which is connected by wire 29 to one terminal of the battery 36. The other terminal of the battery 36 is connected to the hell or lamp C as shown in Figure 7.

Forward movement of the rod 14 will carry the collar 20 forwardly into contact with contact member 25 and when the switch D is in closed position, will close the circuit which will cause an audible or visible signal from the hell or lamp C.

A plummet line 31 is connected to the forward end of the rod 14 and the opposite end of the plummet line 31 is connected to a plummet 32. The plummet is preferably made of a heavy brass rod or some other rust-resisting metal and the opposite ends of the rod are bent at right angles to the central portion in the manner illustrated in the drawings, the bent arms of the plummet lying in the same general plane.

I have found that a plummet of this shape works quite successfully and does not dig into the bottom but it will be understood that the plummet can be of any shape so long as it does not dig into the bottom or roll or slide with the current.

The operation of the alarm device is as follows:

When the vessel A has been anchored in the usual manner as illustrated in full lines in Fig. l by means of the anchor 33 attached to the bow of the vessel by anchor line 34, the plummet line is attached to the forward end of the rod 14 and the plummet is dropped over the side to lie on the seat bottom below the bow of the vessel. The switch D is then closed. The plummet line should be of sufficient length to allow a few feet of slack line to lie on the bottom.

If now the anchor should become fouled by the anchor line or lose its hold on the bottom, the vessel will move away from its anchorage and the pull of the dragging anchor on the bow will tend to turn the bow of the vessel into the wind or into the current. This movement of the vessel will also take the slack out of the plummet line and cause the plummet to drag along the sea bottom. When this occurs, the plummet line will exert a forward pull on the rod 14 and when this pull has become sufiicient to overcome the tension of the spring 16 and the friction of the rod within the tube, the rod will move forwardly in the tube 9 bringing the metallic collar 20 into contact with the contact member 25, thus closing the 3 circuit to ring the bell or light the lamp C, thus indicating to those on board the vessel that the vessel is drifting with the anchor dragging.

It is to be noted that since the dragging anchor will tend to keep the bow of the boat into the wind or current,

the plummet line in dragging the plummet will also stream out in the general direction of the anchor line in a vertical plane generally parallel to the fore and aft axis of the boat so that the pull on the rod 14 will be forward, in the general direction of the anchor line. The general slanting of the tube 9 and rod 14 will tend to reduce the angle between the rod 14 and the plummet line and I have found that in general practice it is desirable to arrange the parts so that any position of the plummet line within an arc of about 30 forward of the vessel will exert suflicient pull to cause the rod 14 to move forward when the plummet is dragging. In this connection it is to be observed that it is important that the plummet lie on the sea bottom rather than being suspended above the bottom for if the plummet is suspended above the bottom, it will not exert sufiicient drag by movement through the water to exert a pull on the rod 14.

It is obviously not desirable that the alarm be actuated when the vessel is moving in its anchorage circle with the anchor holding. If this occurs the angle between the plummet line, attached to the plummet beneath the bow, and the rod 14 will be such that the pull on the plummet line is very nearly at right angles to the axis of the rod. When this occurs the tension of the spring 16 and the friction between the rod 14 and tube 9 is such that the lateral pull of the plummet line on the rod will not cause it to move. This position of the plummet and plummet line is indicated in dotted lines in Fig. 2 where it will be observed that the plummet line is substantially at right angles to the rod 14. From the foregoing it will be understood that the vessel can move freely in its anchorage circle without actuating the alarm for the only effect on the plummet is to drag it in a circle on the bottom corresponding to the circle described by the bow of the vessel in moving about the anchor, and this will not exert a pull on the plummet line which will move the rod 14 forward.

My improved alarm device may be installed on the bow of any small craft in a relatively short time. It can be adjusted by the turning of the screws 18 to increase or decrease the tension of the spring 16 to allow for difference in pull by the plummet due to different types of anchorage bottoms and will make the anchoring of small vessels very much safer. When the vessel is anchored with persons aboard, it is normally preferable that the alarm device be audible. However, when the vessel is anchored in a yacht basin, a warning light is preferable if no one is aboard to warn attendants of the outbasin that the vessel may be dragging its anchor.

I claim:

1. A drift alarm device for vessels comprising an alarm actuating member, means for mounting said member on a vessel providing for fore and aft movement thereof while providing against lateral movement thereof, yielding means for normally holding said member in nonalarm position, a warning signal actuated by movement of said member from its normal position, a plummet line secured to said member and a plummet secured to said line and adapted to lie on the sea bottom when the vessel is at rest.

2. A drift alarm device for vessels comprising an alarm actuating member, means for mounting said member on a vessel providing for fore and aft movement thereof, yielding means for normally holding said member in nonalarm position, a warning signal actuated by movement of said member from its normal position, a plummet line secured to said member and a plummet secured to said line and adapted to lie on the sea bottom when the vessel is at rest, the mounting means for said alarm actuated member being so constructed and arranged as to permit movement of the member only in response to a forward pull by the plummet line.

3. A drift alarm device for vessels at anchor comprising an alarm actuating member, means for mounting said member on a vessel providing for fore and aft movement thereof, yielding means for normally holding said member in non-alarm position, a warning signal actuated by movement of said member from its normal position, a plummet line secured to said member and a plummet secured to said line and adapted to lie on the sea bottom when the vessel is at rest, the mounting means for said alarm actuated member being so constructed and arranged as to permit movement of the member only in response to a pull by the plummet line in the general direction of the anchor line.

4. A drift alarm device for vessels comprising an alarm actuating rod, means for mounting said rod on the vessel providing for fore and aft lengthwise movement thereof,

' while providing against lateral movement thereof, yielding means for normally holding said rod in non-alarm position, a warning signal actuated by forward movement of said rod from its normal position, a plummet line secured to said rod and a plummet secured to said line and adapted to lie on the sea bottom when the vessel is at rest.

5. A drift alarm device for vessels comprising an alarm actuating rod, means for mounting said rod on the vessel providing for fore and aft lengthwise movement thereof, yielding means for normally holding said rod in nonalarm position, a warning signal actuated by forward movement of the rod from its normal position, a plummet line secured to the rod and a plummet secured to said line and adapted to lie on the sea bottom when the vessel is at rest, the mounting means for said rod being so constructed and arranged as to permit movement of the rod only in response to a forward pull by the plummet line.

6. A drift alarm device for vessels at anchor comprising an alarm actuating rod, means for mounting said rod on a vessel providing for fore and aft lengthwise movement thereof, yielding means for normally holding said rod in non-alarm position, a warning signal actuated by forward movement of said rod from its normal position, a plummet line secured to said rod and a plummet secured to said line and adapted to lie on the sea bottom when the vessel is at rest, the mounting means for said rod being so constructed and arranged as to permit movement of the rod only in response to a pull by the plummet line in the general direction of the anchor line.

References Cited in the file of this patent UNITED STATES PATENTS