Garmin GTU 10, a remote anchor watch?


I’m pretty impressed with the Garmin GTU10 I’ve been testing this summer. Inside that little IPx7 waterproof case is a sensitive GPS, a GSM cell modem, and a fairly able lithium ion battery. For $200 you get the hardware, a cute case (meant primarily for hanging on a dog collar), and a one year standard data subscription which normally costs $50. The subscription doesn’t get you much in terms of remote tracking — just the last ten points, whose spacing will vary with settings — but you do get unlimited notifications about when the GTU 10 enters and/or leaves up to 10 geofence areas that you can define at, or with the free Android and iOS Garmin Tracker apps. And aren’t geofences the key to knowing that your boat or tender are where they’re supposed to be, especially when anchored?…

Well, Garmin didn’t really design the GTU 10 for anchor watch duties, but it’s useful nonetheless, and a tweak or two might make it near perfect. The problem is that the maps you build a geofence on are not charts and also your current position doesn’t show on them, both of which make it hard to define the small area you want to be warned about wandering out of. And both of which could be fixed, I think.
   I was still able to create a working anchor watch geofence during the recent weather scare, as you can see in the screens below. In fact, I use a number of geofences as shown in the second screen. The third shows that you can set up different power usage settings, which make a big difference on battery life. And the fourth shows how your phone’s actual position does show up on the regular map view. If the phone and GTU are miles apart — as might be the case if someone ran off with your dinghy — the app will even set up go-to navigation to the GTU.
  The fifth screen shows some of the detailed info you get when you “locate” the GTU, though it must be said that getting the GTU to respond can sometimes take several minutes or longer. I’m not sure why that is, as the GTU can be very quick about geofence notifications (depending on settings), but it’s certainly been noted in other reviews (like GPSTrackLog’s, which also links to others)…


Of course the GTU is pretty useless if it doesn’t have cell access or you don’t have Internet access. But Garmin is using AT&T and, as those screens above also illustrate, my iPhone was only showing minimal AT&T coverage where I was anchored. Had I actually used the GTU to monitor Gizmo from afar, I would have been nervous about that coverage. However, moments after I steamed out of my tropical storm Irene geofence, I got a text about it on my other (Verizon) phone, as I did after passing through my Camden Harbor entrance geofence and again when I tendered out of my tiny Gizmo mooring geofence. I’ve gotten quite used to those text beeps, illustrated by some parallel emails below, and it doesn’t matter if the GTU is in the cabin, my backpack, or pocket…


The GTU10 can also serve as a USB GPS source for a PC, though Garmin doesn’t mention that feature anywhere I can find. In fact, I was surprised one day when I was charging the unit and a just-opened charting program used it to plot precise position. And today I discovered that the GTU can do amazingly detailed tracking if you purchase the extra $5 a month plan. If you could drill in on the MyGarmin screen below, you’d see my bike ride down to the store for an afternoon snack detailed by the minute and as is you can see yesterday’s Gizmo return through the geofences referenced above. If I was into stalking myself, I’d love the GTU (seriously, that’s the downside of these GPS trackers).
   At any rate, while I think the GTU can be useful to boaters, I can’t help but imagine what Garmin could do by mixing the resources they developed to support it with the GDL 40 cellular weather system they introduced last spring. I’ve been testing it too, and it continues to perform well as discussed in June. But, darn, that means I already have Garmin cell modem installed high on Gizmo and connected to, and powered by, its NMEA 2000 network. Wouldn’t it be neat to communicate with the GDL via one of Garmin’s apps? Come to think of it, wouldn’t it be neat if Garmin put an anchor watch screen on its GMI 10 instruments and/or its MFDs, so I could monitor onboard or off? I really have no idea what Garmin is up to in this regard, but aren’t the possibilities interesting?


Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now pleased to have Ben Stein as a very able publisher, webmaster, and editing colleague. Please don't regard him as an "expert"; he's getting quite old and thinks that "fadiddling fumble-putz" is a more accurate description.

10 Responses

  1. dean says:

    I do this at the moment with my iPad (thats left on the boat), and iPhone (thats in my pocket). With Apple’s Find My Phone. Its all free with the system I already have.

  2. Ben Ellison Ben Ellison says:

    Dean, you’re well set up to use the Boat Monitor app and service. For $5, it would give you a serious anchor watch, not just a look at where your boat is. I wrote about it here:
    I’ve now tried the iOS version and it’s nice. It even has the pie slice exclusion zone that is favored by anchor watch afficionados:

  3. Ben Ellison Ben Ellison says:

    Interesting: A UK company called AnchorWatch is offering a 12v load cell and LCD monitor designed to measure the strain you put on an anchor when setting it and then to alarm you if the working strain exceeds a tested max:
    I don’t see any facility for off boat monitoring but it seems like that could be easily added in a future version. The current model costs about $300. Thanks to reader Richarad Ross for the reference.

  4. James says:

    Smartphone apps like AnchorAlert are good options, which I have on my Android, but they’re GPS dependant. In the Pacific NW those cruising into BC and SE Alaskan waters know that some anchoring locations have very steep mountains that can reduce and even obscure GPS signals. Although DeepBlue AnchorAlert is more expensive, it’s another good non-GPS sensor solution for anchoring.

  5. HenryD says:

    This is interesting but I am not sure I want to tie into cellular / internet. Most of the time I am looking for an anchor watch solution when I am at anchor and want to sleep.
    My 10 yr old Raymarine RL80 has a very function anchor alarm but that is up in the pilot house. It is interesting that the newer systems do not have this basic feature. I have Rosepoint which does not have an anchor watch…it can get me to the anchorage, but then I am on my own. I have NMEA2000 with GPS input into the backbone, but N2KWatch cannot do an anchor watch without upgrading to a many thousand dollar version. It also cannot send me messages to my iPad or telephone without this upgrade.
    I need to replace my two displays and chartplotter but until I find a solution that meets my needs, I will stick with the older technology.
    Garmin seems to be headed in the correct direction.

  6. scott says:

    isnt this Very simular to the boat sense device that hamilton marine was selling? if so the Cell coverage issue up here in maine is a very real downer to the use of this. The price is better though!

  7. Ben Ellison Ben Ellison says:

    Well, the GTU10 is a portable GPS tracker while Boatsense ( ) is a fixed boat monitoring system, but they both do use GSM cellular. I think that at least AT&T service is a little better than it was around here, though still mostly Edge data rates. I’ve only had the GDL 40 fail to deliver weather once this summer, but then again its antenna is up on the flying bridge rail.

  8. Hair of the Dog says:

    The current crop of Garmin units have an “Anchor Drag” alarm built in. They allow you to set an alarm radius and if you exceed that distance….they will alarm. They also have the ability to trigger a remote alarm so you could mount an additional buzzer near the captains berth to increase the odds you will hear it.
    Sleep tight….

  9. Frank Burrows says:

    The problem with the Garmin alarm is that you have to set it when you drop your anchor or the circle will not be valid since it is not centered on the anchor. The Android application asks the distance to the anchor and the direction. It draws a circle around the anchor. The person who wrote AnchorAlert obviously anchors a boat. It is hard to understand why Garmin can’t/won’t do this.

  10. Pandora says:

    Funny, that was also my comment about Furuno an hour ago. Why the big manufacturers can’t see this is beyond me.

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