Anchor alarm apps - a comprehensive survey

[Flatswing]

Originally Posted by Nicholson58

I prefer the anchor watch feature on our Watchmate AIS. Very low power consumption and the AIS is on always anyway. The screen at a glance shows where we are on our circle and where we have been no matter how long we are at anchor. We have pads and smart phones but all need charging and are used for other things. I consider the apps a back-up band-aid. The Watchmate is purpose built and never walks away. Fringe benefit is our designated fleet friends can find us easily.

I have the 8000xb, which does not have a hardwired screen and must be controlled & viewed on an Android or iPad/phone via built in WiFi. With the external GPS antenna this is very accurate. One can reposition anchor location if you missed the exact drop location first time. Occasionally, the WiFi connection drops to a given portable device, but, since the tracking data is stored on the hardwired 8000xb, no false alarms. As soon as the WiFi is restored, all the position tracking data returns on whichever device I am using. We use it frequently anchoring in 2-5 knots reversing current here in the SE & never use the Drag Queen/Anchor watch apps any more.

[Nicholson58]

Our AIS is a Watchmate 850. Uses 7.5 watts in anchor watch mode. Visual screen shows where you are and where you have been. I added an aux GPS antenna but it is buried in the fiberglass binnacle enclosure. This has never been a problem. I think the whole “clear view of the sky” thing is way overblown. My cell phone, pads hand held GPS have never had any trouble indoors except parking garages and non window seats of aircraft.

[noelex 77]

Originally Posted by Flatswing

I have the 8000xb, which does not have a hardwired screen and must be controlled & viewed on an Android or iPad/phone via built in WiFi. With the external GPS antenna this is very accurate. One can reposition anchor location if you missed the exact drop location first time.

The Vesper is the best anchor alarm I have used so far (we have the Vesper Vision). Having a hardwired marine device with no other software and an external aerial solves the hardware limitations when using the apps.

In addition, it is the only anchor alarm that I am aware of that translates the position to the bow (providing you have heading on MNMEA bus). This reduces some of the errors. The resulting tight plotter trace makes it easier to pick up minor movements of the anchor. (Unfortunately this feature on our Vesper has stopped working over a 180° arc due to some unknown software problem.)

[JBP]

That is awesome, thank you for putting all that together.

When you say "NMEA Interface", I assume that means NMEA 0183 over wifi since most phones don't have physical NMEA connections?

May I suggest you add the developer name in addition to the app name, since so many are named "Anchor Watch" or "Anchor Alarm"

You might also provide a blank evaluation form for us to help with the ones you haven't been able to test.

[noelex 77]

Originally Posted by Nicholson58

I added an aux GPS antenna but it is buried in the fiberglass binnacle enclosure. This has never been a problem. I think the whole “clear view of the sky” thing is way overblown. My cell phone, pads hand held GPS have never had any trouble indoors except parking garages and non window seats of aircraft.

It will always establish and maintain a reliable fix with this type of installation. Hence it will always "work", but the quality of the fix is less than optimum. The anchor alarm needs a very tight fix that is on the limits (or ideally better than) most marine GPS units are capable of achieving even with a good view of the sky and differential correction.

When the fix quality is reduced the alarm is still useful. There are many anchorages where it will work perfectly, but even with an ideal installation there are some situations that are too tight for a useful warning of even a slow drag. The greater the dither and variation in GPS position, the more anchorages like this that will be encountered.

[SV__Grace]

Be sure your anchor alarm app works on your phone!


Don't take it for granted and here's why- I've used an anchor alarm app on my phone at night when sleeping and discovered that the position wasn't updating. I download other apps, same problem. I have an up to date iPhone and after years of using anchor alarm apps, the position no longer updates no matter what setting or what app is used.


I tested using my wife's iPhone, my iPad, and a cheap Android phone, same problem. I test using a high quality Android phone and it worked.


Since we live on the hook and I like to sleep well at night with a good anchor alarm, I invested in a small chartplotter (B&G Vulcan) for our stateroom with a loud external alarm.


So for a long time I ASSUMED my anchor alarm app worked and it did not. It would stop working after awhile when put down, and would start working again when picked up, which is really decieving. I only discovered the problem after we swung far enough to notice before picking up the phone that the position hadn't moved.


I contacted the developer of the app I had been using, who also happens to be the previous owner of our boat, and he tested the app, including using his car as a substitute moving boat, and couldn't find or replicate the problem.


Does you app really work? Be sure to test in real world conditions and don't assume it does as appearances are decieving.

[Kelkara]

Originally Posted by SV__Grace

Be sure your anchor alarm app works on your phone!


Don't take it for granted and here's why- I've used an anchor alarm app on my phone at night when sleeping and discovered that the position wasn't updating. I download other apps, same problem. I have an up to date iPhone and after years of using anchor alarm apps, the position no longer updates no matter what setting or what app is used.


I tested using my wife's iPhone, my iPad, and a cheap Android phone, same problem. I test using a high quality Android phone and it worked.


Since we live on the hook and I like to sleep well at night with a good anchor alarm, I invested in a small chartplotter (B&G Vulcan) for our stateroom with a loud external alarm.


So for a long time I ASSUMED my anchor alarm app worked and it did not. It would stop working after awhile when put down, and would start working again when picked up, which is really decieving. I only discovered the problem after we swung far enough to notice before picking up the phone that the position hadn't moved.


I contacted the developer of the app I had been using, who also happens to be the previous owner of our boat, and he tested the app, including using his car as a substitute moving boat, and couldn't find or replicate the problem.


Does you app really work? Be sure to test in real world conditions and don't assume it does as appearances are decieving.

I think the problem here is that android (and maybe ios) will turn off the gps to save power if it thinks you are sleeping. I haven't dug into the details, but it probably uses the accelerometer to detect movement. Maybe the smooth slow movement of a boat gently swinging isn't enough to register, but perhaps once the wind picks up before the anchor breaks free it will have turned on again.

I was thinking of writing an anchor alarm app, but came across problems like this, and never did enough research to find ways round them.

[noelex 77]

Originally Posted by SV__Grace

Be sure your anchor alarm app works on your phone!

Good point. We don't often cancel our anchor alarm when leaving the anchorage or adding more scope. Sometimes we even remember and still deliberately don't cancel our anchor alarm .

The alarm provides proof that the system works and helps remind you what the alarm sounds like. There is plethora of alarms on modern sailboats and it is helpful to be able to distinguish from the sound alone what type of alarm is occurring.

When adding extra scope the test is particularly valuable, as it will show the alarm sensitivity in the real world.

As has been pointed out, these tests are essential on phones/tablets where the app can be disabled for a variety of reasons. It may not be apparent that this is occuring. Here you have the additional option of taking the device ashore in the tender to determine the functionality and sensitivity.

[Nicholson58]

Originally Posted by noelex 77

The Vesper is the best anchor alarm I have used so far (we have the Vesper Vision). Having a hardwired marine device with no other software and an external aerial solves the hardware limitations when using the apps.

In addition, it is the only anchor alarm that I am aware of that translates the position to the bow (providing you have heading on MNMEA bus). This reduces some of the errors. The resulting tight plotter trace makes it easier to pick up minor movements of the anchor. (Unfortunately this feature on our Vesper has stopped working over a 180° arc due to some unknown software problem.)

Vesper is very good about servicing their installed units. I have had both software and electrical failure (lightening hit). Both times they rebuilt and upgraded mine for a low charge. You can get a software upgrade on line. Just contact them.

[noelex 77]

Originally Posted by Nicholson58

Vesper is very good about servicing their installed units. I have had both software and electrical failure (lightening hit). Both times they rebuilt and upgraded mine for a low charge. You can get a software upgrade on line. Just contact them.

Thanks. I have done that, but unfortunately they don't seem to be able to resolve the problem. The feature worked perfectly with my Vesper Vision, but when this was replaced with the Vision 2 the heading works only over 180°. On all other displays the heading works normally.

[MathiasW]

Originally Posted by JBP

That is awesome, thank you for putting all that together.

When you say "NMEA Interface", I assume that means NMEA 0183 over wifi since most phones don't have physical NMEA connections?

May I suggest you add the developer name in addition to the app name, since so many are named "Anchor Watch" or "Anchor Alarm"

You might also provide a blank evaluation form for us to help with the ones you haven't been able to test.

Thank you! And yes, it is NMEA over wifi, as far as I understand it. I just had the documentation and had a chat with the developer.

Adding the developer details is an excellent idea. I had used the icons as a means to differentiate all these alarms.

A blank form is also a good idea. But one can leave comments at the bottom of that page as well.

Cheers, Mathias

[MathiasW]

Originally Posted by Kelkara

I think the problem here is that android (and maybe ios) will turn off the gps to save power if it thinks you are sleeping. I haven't dug into the details, but it probably uses the accelerometer to detect movement. Maybe the smooth slow movement of a boat gently swinging isn't enough to register, but perhaps once the wind picks up before the anchor breaks free it will have turned on again.

I was thinking of writing an anchor alarm app, but came across problems like this, and never did enough research to find ways round them.

In my understanding both iOS and Android introduced more aggressive power saving modes in their OS's not too long ago. So, this can mean that the app stops working as soon as it is pushed into background. Some apps suggest to keep the app always on the top of the screen, whilst others even have a button to push the app to the background (and still let it do its work).

I have heard of cases where playing a game on the phone or tablet caused the operating system to purge all tasks that it did not deem essential. Including the Anchor Alarm.

All this means that new OS updates can mean the Anchor Alarm stops working, so do not install a new update just before you want to go to your sailing vacation. It also means to me that I want an app that is continuously upgraded by the developer to stay on top of things like this.

Cheers

Mathias

[waterman46]

From these posts it appears that the most reliable and easy to use anchor watch solution is a stand-alone unit like the Vesper Vision series. Cost about $1200. I hope the power requirement in the anchor watch mode is low (does it blank the screen?)

The next cheaper solution is to run an app all night on chartplotter or PC, since we already have those, with connection to a good GPS data source - could be WiFi or wired, from an AIS or any other GPS source on the NMEA network which we already have. Very low cost but problem to me is current consumption of chart plotter or PC plus GPS data source. I don't want to be drawing 5A for 8 hours.

Cheapest is using a smartphone with free app and external GPS antenna. Very low power consumption. False alarms or no alarms when the phone decides it doesn't want to run the app in background mode.

I ordered a $20 external GPS antenna with booster and we'll see if that fixes my false alarm issue with any of the Android apps.

[SV__Grace]

Originally Posted by Kelkara

I think the problem here is that android (and maybe ios) will turn off the gps to save power if it thinks you are sleeping. I haven't dug into the details, but it probably uses the accelerometer to detect movement. Maybe the smooth slow movement of a boat gently swinging isn't enough to register, but perhaps once the wind picks up before the anchor breaks free it will have turned on again. I was thinking of writing an anchor alarm app, but came across problems like this, and never did enough research to find ways round them.

I've played with all the settings and asked smart IT people as well and the problem continued.


BTW, I used velcro to mount by cell phone on the hatch above my bed for a clear view of the sky.


I think it's significant that the expensive Android device DID work.



I suspect that some iOS update messed up the ability for these apps to work for me after working successfully for years Or did they really work all these years?



My point is to not accept on faith that your anchor alarm app on your phone continues working after you put it down- check and test.

[MathiasW]

So, an update to the anchor alarm survey is now available on https://trimaran-san.de/anchor-alarm-apps-overview/ . The new apps are all navigational apps that also feature an anchor alarm. For most it is pretty basic, but TZ iBoat actually seems to be pretty decent in its feature list.

Cheers, Mathias