Anchor Alarm

[dom]

Following the anchor vs. mooring theme does anyone know of an anchor alarm that would really act as alarm clock? My B&G chartplotter has an alarm that is far too quiet to rely on. Perhaps others have a DSC alert type of alert tone which nobody could sleep through!

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[Benbow]

Most GPS units have an alarm output that you can use to drive a small (reed type) relay that can in turn switch almost anything you like including a very loud alarm. All the bits you need for this are avaialble from places like Maplin for a pound or 2.

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[dom]

Sounds like a great idea. I will give it a go at the w/e. Having mainly raced boats I don't know that much about anchoring and would feel much better knowing I would wake up if the boat moved!

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[dom]

Sounds like a great idea. I will give it a go at the w/e. Having mainly raced boats I don't know that much about anchoring and would feel much better knowing I would wake up if the boat moved!

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[starboard]

Hi DOM, As I placed the original thread dont be affraid to go out and try. I take every precausion necessary to protect my boat. The GPS anchor alarm is set to 0.03nm that is sufficient that as the boat swings in the tide/wind the alarm will not sound unless you actually start to drag. The problem with my Furuno GP30 is that the alarm only sounds once but have never slept through it...even after a few drams!! I also set the alarm on the echo sounder so if I am in 5m I will set the deep alarm to 10m and the shallow to 2m. This will alow for a rise and fall of 3m tide, about normal up here in Scotland but shoul I drar into deeper/shallower water the alarm will go. All this is more critical up here on the West coast of Scotland due to deep water until about 20m off shore, this means anchoring very close inshore but well worth the effort. After you have slept many nights like this you will wonder why you ever trusted someone else's mooring with all the possible unknowns that will entail. Good luck and peaceful nights.

Paul.

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[dom]

You are most probably so right about giving it a go. I like many many others have raced boats all my life but only anchored in light winds to wait out a tide. Here in the solent there is often quite a rush to get moorings on Saturday evenings as many of us (racing backgrounds that is) whilst happy to sail through some nasty blows become deeply concerned at anchor. I used to think that anchoring was the preserve of boats that were prepared to carry enormous contraptions on their bow but have subsequently realized how wrong that is. Could be fun!

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[extravert]

From my recent boat performance data logging project, where I have all boat data from NMEA or Seatalk coming into my phone (which then plots and logs the data) I have been pondering other ideas. One of these was an anchor alarm.

The idea I had in mind was that software on the phone would monitor GPS position, Speed Over Ground, depth and windspeed, and if any of these went outside pre-defined limits, then the phone would alarm. It could also send a text message to another phone with information on why an alarm was triggered if noone was on board at the time. The boat monitoring system could also send back a status report on request by text message.

Although this doesn't solve your problem at the moment (it will be my winter project for this year), do people think that this sort of capability would be useful? I will make all the details public if I go ahead.

<hr width=100% size=1>One day, I want to be a real sailor. In the mean time I'll just keep tri-ing.

 

[Benbow]

Can you really do this with just a mobile phone ? I had no idea they were so pragrammable. Presumably the software would be very model-specific ?

I had wondered about making something similar, for me a key additional input would be from sensors on a burglar alarm. But I had assumed I would need a laptop to handle the data and a phone just to send out alerts.

An interesting alternative for boats in areas with wireless broadband access would be a mini web server. That would be fairly easy to implement and could show all that data in near real time. Could include bilge alarm, low voltage and lots of other useful stuff, you could even have a webcam !



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[Beagle]

Seems to me a very interesting project. Please do go ahead this winter and I will be looking forward to all the details!

Cheers, Rene

<hr width=100% size=1>Never under estimate the strength of human stupidity

 

[extravert]

The latest top end mobile phones are called 'open platforms', which means that you can install new software yourself. They must have an open operating system, like Symbian, Microsoft Smartphone or PalmOS. Although these phones are top-end at the moment, they soon won't be.

You could easily use a laptop for the monitoring and use a phone to send the alerts, but you are using 2 powerful computers where one would do. A phone also uses trivial electrical power compared to a laptop.

You might be able to run a webserver on a laptop and use GPRS for the internet link, but it could get expensive if your website became too popular. Imagine everyone here logging in to see a live picture of your bilge

<hr width=100% size=1>One day, I want to be a real sailor. In the mean time I'll just keep tri-ing.

 

[Benbow]

Interesting information thanks.

Webserver: as I say, only viable with wireless broadband which I believe some marinas have. I would also make it password protected !

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[extravert]

Now I\'m just pratting about...

I've just installed and fired up a webserver on my phone, connected to the internet by GPRS. No laptop required. It works fine, but I took it offline again after one download by my colleague on the other side of the room. Could get expensive.

Details can be found <A target="_blank" HREF=http://my-symbian.com/UIQ/applications/applications.php?fldAuto=160&faq=6>here</A> if anyone else is sufficiently geekish enough to be interested.

<hr width=100% size=1>One day, I want to be a real sailor. In the mean time I'll just keep tri-ing.

 

[Sybarite]

Take a sauce pan and tie a loose loop around the handle. At the other end of the line tie a heavy weight and hang it over the side of the boat to the minimum depth acceptable for your boat. Hang the saucepan in the companionway in such a fashion that the tension on the line stops it from falling. As soon as the weight touches the bottom the tension goes off the line and the pan falls.

Try sleeping through this high tech approach....!

John.

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[MainlySteam]

The anchor watch alarm on our GPS is not very loud but we have never slept through it (well as best as we can tell, of course, but it seems to wake us instantly even though we are sound sleepers).

I have an organizer which has an alarm which is also not very loud but is almost the exact same frequency and repeat rate (several times per second) as the GPS and I rely on that when travelling to wake me for planes etc and have never slept through it either even when very tired.

I wonder if there is some research which shows this tone and repeat rate to be a reliable alert even for sleepers, and even though not very loud? We have never dragged at night so the alarm only goes because of the tightness of the setting or being set off centre from the swinging circle. If the alarm was very loud we would probably set the watch with more drag allowed and therefore more dangerously in order to stop ourselves being frightened out of our wits at night.

It might be that a quieter but effective alarm is safer than a loud one?

John

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