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Old 07-14-2013
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Anchor Drag Alarm

I've been using my Garmin 376C plotter as an anchor drag alarm. It works quite well, can be set right next to where I sleep, and has a nice loud signal. But it also requires that the unit be left on all night and then it needs to be recharged from almost 0 next morning. I have been thinking about the possibility of a simple mechanical device that would reliably detect slippage. It seems to me that after anchoring, a small second weight/anchor could be lowered over a rail and set to trigger a switch on any backward motion if attached to a mechanical rig. Rotating around the main anchor with current would create sideways movement on the rode and not trigger the system. Only substantial backward movement on the rode relative to the main anchor would set it off. Has anyone seen a design for something like this? I'm thinking maybe a s.s. ring with a slot. If the rode falls in the forward facing slot, it hits a switch arm, powering a beeper.
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Old 07-14-2013
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Re: Anchor Drag Alarm

I suppose your idea might work, but do you want to trust your boat to it? The 12V adaptor for that unit is about $40 retail and can most likely be bought for less. Would seem to solve your problem.
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Old 07-14-2013
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Re: Anchor Drag Alarm

Quote:
Originally Posted by smurphny View Post
I've been using my Garmin 376C plotter as an anchor drag alarm. It works quite well, can be set right next to where I sleep, and has a nice loud signal. But it also requires that the unit be left on all night and then it needs to be recharged from almost 0 next morning. I have been thinking about the possibility of a simple mechanical device that would reliably detect slippage. It seems to me that after anchoring, a small second weight/anchor could be lowered over a rail and set to trigger a switch on any backward motion if attached to a mechanical rig. Rotating around the main anchor with current would create sideways movement on the rode and not trigger the system. Only substantial backward movement on the rode relative to the main anchor would set it off. Has anyone seen a design for something like this? I'm thinking maybe a s.s. ring with a slot. If the rode falls in the forward facing slot, it hits a switch arm, powering a beeper.
This design can create more trouble than it solves.

Most try to avoid using two anchors..
What if your system works "Rotating around the main anchor with current".
And anchor alarm is triggered by "substantial backward movement on the rode relative to the main anchor".

Do want to have to untangle the two rode's before you fix the problem.
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Old 07-14-2013
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Re: Anchor Drag Alarm

Yep! I use a fishing sinker and line. Tie it around my .... ummmmm around my Little .... finger... and when I feel a little tug....


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Old 07-14-2013
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Re: Anchor Drag Alarm

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Originally Posted by tomandchris View Post
I suppose your idea might work, but do you want to trust your boat to it? The 12V adaptor for that unit is about $40 retail and can most likely be bought for less. Would seem to solve your problem.
I think something like could very possibly work and be as reliable as a GPS. A GPS has to have a setting at greater than the diameter of your swing circle to account for change in current and or wind. This can be a considerable distance. With a mechanical system like this, the slippage could be limited to a very short distance before it would trigger the alarm.
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Re: Anchor Drag Alarm

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Originally Posted by knuterikt View Post
This design can create more trouble than it solves.

Most try to avoid using two anchors..
What if your system works "Rotating around the main anchor with current".
And anchor alarm is triggered by "substantial backward movement on the rode relative to the main anchor".

Do want to have to untangle the two rode's before you fix the problem.
The weight for this would be directly below the boat, not as another anchor line. I'm thinking possibly a 5# weight or a small mushroom type dink anchor that goes almost straight down with just enough angle so the line can rotate around a pivot point. It could be quite small and be mounted anywhere along a horizontal rail or at a stanchion. It could even be mounted at the stern because all it would need to do would be to detect X' of backward movement. I can see a possible problem from really swift current on the line but a small line, maybe some 200# mono, with a relatively heavy weight might solve this.
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Old 07-14-2013
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Re: Anchor Drag Alarm

Try Drag Queen. A mobile phone/ tablet app. It has a loud alarm.

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Old 07-15-2013
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If you set the alarm to a tight radius, painting back and forth can trip it. Set it to a wide radius in a tight anchorage and its useless.

I have read of someone developing a sensor that attaches to the anchor and wirelessly transmits a warning if it moves. Don't know anything more about it.
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Old 07-15-2013
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Re: Anchor Drag Alarm

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Originally Posted by smurphny View Post
The weight for this would be directly below the boat, not as another anchor line. I'm thinking possibly a 5# weight or a small mushroom type dink anchor that goes almost straight down with just enough angle so the line can rotate around a pivot point. It could be quite small and be mounted anywhere along a horizontal rail or at a stanchion. It could even be mounted at the stern because all it would need to do would be to detect X' of backward movement. I can see a possible problem from really swift current on the line but a small line, maybe some 200# mono, with a relatively heavy weight might solve this.
I hadn't really thought about a manual system but thinking about a weight separate from the anchor tells me of a bunch of problems with the boat swinging on temporary wind shifts or a tide change. The boat then moves around the anchor but not around the alarm weight and that doesn't really constitute anchor drag because the alarm will sound while the anchor is still firmly set.

So how about a light line with its own weight/anchor but threaded through the main anchor eye or similar. So when you set the anchor the smaller weight gets sort of left behind and sets itself separately if you will and that is good because whilst it is actually separate from the anchor, it pivots around the same point.

Once the main anchor is set, take out the slack from the light line and connect it to whatever alarm you're planning on using. So if the anchor now drags, the little weight/anchor gets left even further behind and tugs on the alarm.

I haven't ever tried this and do not offer it as anything more than just an idea. It may work though . But if you use it and it doesn't work I won't apologise.
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Re: Anchor Drag Alarm

Chef, have seen the Drag Queen iphone app. iphone technology looks like the future of electronic boating. The app has mixed reviews. I have multiple electronic GPS-based options on computers and on handheld GPS devices but am trying to think of something NOT GPS or IC based, something more mechanical and simple in nature, something that draws 0 amperage with only a switched circuit as the electrical component.

I don't think anyone is picturing what I'm talking about: a s/s ring with a slot/ a break into which the weighted line can fall only when/if the boat pulls in one specific direction-in line with the c/l of the boat moving astern. With anchor set, it is not possible for a boat to move directly away from the anchor point outside the radius of the anchor line. Various current/wind conditions often cause the boat to sit sideways to the anchor and swing back and forth around the radius but I really can't visualize a condition when the boat would move directly away from the anchor so that a line would be parallel to the c/l except for the condition of the anchor slipping.

The problem with the idea is that a boat could slip anchor and never move directly away from the anchor in the parallel position necessary for the line to drop into the slot.
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