Results 1 to 25 of 25

Thread: Advice needed for marine GPS device

  1. #1
    Join Date
    Dec 2010
    Location
    North Central Vermont
    Posts
    26

    Default Advice needed for marine GPS device

    Hello-
    I will need to outfit a 22 foot motorboat with a GPS device for basic safe navigation, mainly around Lake Champlain and Maine intercoastal jaunts. Handheld is fine. Are depth finders often included on these instruments? Limited budget, but want to make a good choice. I think I have heard of folks adapting old iPads and putting them in a water proof sleeve...is this possible/practical? I also have an old Garmin (for road nav) that quickly became obsolete as phones became so smart - would that work (I realize it's not waterproof) ?
    I am looking at a couple of devices on West Marine, such as the Garmin Inreach Satellite Communicator. I certainly don't know what I'm doing here....
    Any advice much appreciated!

  2. #2
    Join Date
    Aug 2006
    Location
    Rockford, IL
    Posts
    12,438

    Default Re: Advice needed for marine GPS device

    You might want to connect your GPS with your VHF radio for MMSI capability. If planning to navigate Canadian waters you would also need to license your radio (station) and yourself (operator) with the FCC. I do not believe handheld GPS units have depth finder capability.

  3. #3
    Join Date
    Oct 2005
    Location
    seattle
    Posts
    20,779

    Default Re: Advice needed for marine GPS device

    I use the Navionics app on my phone as a backup chart plotter on my boat. It’s easily as accurate as my main plotter, just a smaller screen. There are other nav apps for phones as well.

  4. #4
    Join Date
    Nov 2014
    Location
    Seattle, WA
    Posts
    5,343

    Default Re: Advice needed for marine GPS device

    I use an iPhone for backup as well. I've run Navionics and iNavX on it. Both seem to work fine but the small screen is not ideal for a primary nav device unless you are using paper charts for navigation and the GPS for position reference only.

    I have not done this personally, but for a small boat I'd be inclined to run OpenCPN on an Android tablet (or a Windows 10 tablet if that's your preference) with a connection to a compatible NMEA 0183 depth transducer. Currently we run OpenCPN on a Windows laptop and it works great. And if you also get a VHF radio with AIS and NMEA capability you can add AIS to the OpenCPN display as well, which is handy.
    - Chris

    Any single boat project will always expand to encompass the set of all possible boat projects.

    Life is short. Go boating now!

  5. #5
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    23,690

    Default Re: Advice needed for marine GPS device

    Tablet/ Phone nav works just fine... provided you can deal with the small screen, provided you don't get it wet and provided the sun isn't directly on the screen. They will not provide you with the depthsounder function you also asked about.

    For under 300 bucks, you can purchase a combo chartplotter/ fishfinder, that will be waterproof, daylight viewable in sunlight, have a 5 inch diagonal screen and with which you can see the bottom depth ( and more whether you want/ need that or not).

    Here's an example for $300. ( No connection to me)

    https://www.lowrance.com/lowrance/ty...l-5x-splitshot

    Screen Shot 2020-11-09 at 11.55.42 AM.jpg


    On a 22 foot powerboat you have the room and the power ( from the batteries and the engine alternator). Use the mobile device option as a backup for navigation.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  6. #6
    Join Date
    Nov 2014
    Location
    Seattle, WA
    Posts
    5,343

    Default Re: Advice needed for marine GPS device

    ^^ The dedicated devices have a lot of advantages but one major disadvantage in that you may end up locked into a proprietary, and costly, chart format like C-Map, or limited to preloaded charts only. Check before you buy. It's definitely possible to get depth display on a mobile device or tablet but it does take a little more fiddling with technology.
    - Chris

    Any single boat project will always expand to encompass the set of all possible boat projects.

    Life is short. Go boating now!

  7. #7
    Join Date
    Mar 2007
    Location
    East Quogue,NY
    Posts
    23,690

    Default Re: Advice needed for marine GPS device

    ^Comes with free base charts built-in: naviads, soundings, landmasses. And, has real-ime mapping in which you can create custom charts of your local area( great for areas that are not updated frequently or for which you want more detail)

    That said, if one wanted full featured charts, with 3D bathymetric imagery, marina and port information, aerial photos, satellite imagery, etc...that will cost $139 and user can choose between Navionics or C-map.

    The free C-map embedded charts included are plenty detailed:

    Screen Shot 2020-11-09 at 12.41.03 PM.jpg

    Screen Shot 2020-11-09 at 12.40.56 PM.jpg


    That said, one has to choose between "lakes" ( 11,000 lakes) and "coastal", ( entire US coastline) free charts upon purchase. Since OP wants Lake Champlain and Maine coast, he will need to buy one or the other for the additional $140--not too much for a boatowner, I daresay.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  8. #8
    Join Date
    May 2020
    Location
    Dubai, UAE
    Posts
    226

    Default Re: Advice needed for marine GPS device

    Grab an old ipad and download the Navionics app onto it. A waterproof sleeve would probably be a wise investment, as would a battery pack and a charging cable.

    I've got various bits of electronic kit, paper charts and the like on my boat, but the ipad tends to be what I always reach for when I'm simply pottering about. It does about 90% of what I ever want in terms of navigation. They don't have depth finders on them, but the Navionics app shows where you are on its chart, and you can see the approximate water depth at that position.

    Depth sounders are nice to have, but not a necessity. If the water is shallow then slow down a bit, if its very shallow then slow down a lot, if you think it is so shallow that you'll run aground then have someone lean over the side with a boathook and see if they can touch the bottom with it.

    The only other bit of kit I'd suggest getting at the outset is a handheld VHF radio. As with anything, the more you spend the more features they have, but a basic one for under $100 will do the most important thing in that it gives you a means to communicate if there is an emergency.

    In terms of backup for the ipad and the VHF, you can download Navionics onto your phone which gives you a separate stand-alone device for navigation and, well, it's a phone so you can also use it to call for help if needed.

    Personally I prefer not to use my phone as a primary navigation device largely because I quite like to keep the battery charged up in case I need to use it as a phone. I also find the screen annoyingly small for navigation and will invariably leave it in my pocket and sit on the thing / jump in for a swim or, even worse, get a call from someone I escape to sea to avoid...! IMHO phones are best left down below (with the ringer turned off).

  9. #9
    Join Date
    Sep 2010
    Location
    Bainbridge Island WA
    Posts
    4,348

    Default Re: Advice needed for marine GPS device

    Quote Originally Posted by AndanteEd View Post

    Depth sounders are nice to have, but not a necessity. If the water is shallow then slow down a bit, if its very shallow then slow down a lot, if you think it is so shallow that you'll run aground then have someone lean over the side with a boathook and see if they can touch the bottom with it.
    That works if you have crew, it is daylight and/or the water is clear enough to see the bottom. Singlehanding out of a busy harbor with a lot of tidal range and murky water, I rely pretty heavily on my depth sounder to help skirt along the edges of the channel. There can be a pretty big variance between the charted depth and the actual, those numbers are only good on the day they got written down. Having electronics won't absolve you of proper seamanship (seapersonship?) but it sure comes in handy on anything much bigger than a dinghy.
    Steve

    If you would have a good boat, be a good guy when you build her - honest, careful, patient, strong.
    H.A. Calahan

  10. #10
    Join Date
    May 2020
    Location
    Dubai, UAE
    Posts
    226

    Default Re: Advice needed for marine GPS device

    Quote Originally Posted by stromborg View Post
    That works if you have crew, it is daylight and/or the water is clear enough to see the bottom. Singlehanding out of a busy harbor with a lot of tidal range and murky water, I rely pretty heavily on my depth sounder to help skirt along the edges of the channel. There can be a pretty big variance between the charted depth and the actual, those numbers are only good on the day they got written down. Having electronics won't absolve you of proper seamanship (seapersonship?) but it sure comes in handy on anything much bigger than a dinghy.
    Yup, I certainly don't disagree with any of that. I guess all I was saying that for a 22 foot motorboat and a limited budget it is possible to have a safe and enjoyable day on the water without one.

    On saying that I know little about the Maine coast or Lake Champlain, I assume that submerged rocks and tides are a feature of the former, and monsters the latter.

    Breakaway's suggested fishfinder could be a good call for both...?

  11. #11
    Join Date
    Apr 1999
    Location
    Now, there's a long story...
    Posts
    1,699

    Default Re: Advice needed for marine GPS device

    Based on what you've described, the four inch version of this may work for you.

    https://buy.garmin.com/en-US/US/p/59...n/010-01886-05

    You didn't put a number on your budget, but the "problem" I see with the old iPad thing is you need to find one with GPS, or you need to add a GPS receiver to it (BadElf makes one). It's not daylight readable, and it doesn't have the depth you'd like. Yes, you can waterproof it, but that adds to the cost, and if you upgrade to a newer iPad, you're upgrading the case again. On a 22 foot boat, I'm not sure I'd go that direction. The larger screen would be nice (the large screen chart plotters are far more expensive than a similar sized iPad) but at some point you run out of dashboard, too.

    The problem with using the old road GPS is the firmware will try and put you on a road if there is one nearby. I think the nautical term for that is "aground". IF you could set it up where it just gives you the lat/long you could plot that on your chart, but that's a little time consuming, if nothing else. It's also exactly how we did it back in the early '90s, so not unfeasible... just extremely inconvenient and inefficient. But I guess a bit better than DECCA or LORAN.
    Heute ist so ein schöne Tag...

  12. #12
    Join Date
    Nov 2014
    Location
    Seattle, WA
    Posts
    5,343

    Default Re: Advice needed for marine GPS device

    Just to address this point...

    Quote Originally Posted by Don Z. View Post
    The problem with using the old road GPS is the firmware will try and put you on a road if there is one nearby.
    Not really. The firmware (actually the GPS receiver, which is a separate chip in the device) just provides coordinates. It's the given mapping application, like Google Maps, that will try to put you on a road. A real navigation app will not do that. And even then I have found that Google Maps, at least, is pretty good about recognizing that you are in the middle of the water. Not recommended for navigation of course, but just as a point of information. It *is* possible that older GPS receivers may not be as accurate as newer ones but that depends on a bunch of factors and may not necessarily be the case either.

    Also regarding lack of GPS on older iPads. The issue there is that the GPS antenna is on the same chip as the cell service antenna. So if you get a wi-fi only iPad it will not have GPS. You need one that will accept a SIM card.

    And finally it's worth noting that you can buy a waterproof, sunlight-visible Android tablet for about the same price as one of the small, dedicated, multifunction chartplotters like the Lowrance unit posted earlier by Kevin. I think both options have their pros and cons and I am not knocking the dedicated devices at all. If you don't want to mess with technology I think the simplicity of the nav-specific device is probably better. But with a little effort I do think that the tablet offers a lot more functionality, flexibility and upgrade/expansion potential for the money.
    - Chris

    Any single boat project will always expand to encompass the set of all possible boat projects.

    Life is short. Go boating now!

  13. #13
    Join Date
    Jun 2010
    Location
    PNW, an island west of Seattle
    Posts
    2,986

    Default Re: Advice needed for marine GPS device

    Just asking because I don't know jack about it all..... Does a tablet get its position directly from satellites like a regular gps device or from the cell tower?

    Jeff

  14. #14
    Join Date
    Nov 2014
    Location
    Seattle, WA
    Posts
    5,343

    Default Re: Advice needed for marine GPS device

    Quote Originally Posted by jpatrick View Post
    Just asking because I don't know jack about it all..... Does a tablet get its position directly from satellites like a regular gps device or from the cell tower?

    Jeff
    Both, assuming it has a cell connection. But GPS is way more accurate.
    - Chris

    Any single boat project will always expand to encompass the set of all possible boat projects.

    Life is short. Go boating now!

  15. #15
    Join Date
    Nov 2014
    Location
    Seattle, WA
    Posts
    5,343

    Default Re: Advice needed for marine GPS device

    Also I think I may have misunderstood Don Z's point about "road GPS". I thought he was talking about tablet-based GPS mapping apps but in rereading the OP I realized that there was a mention of using an old road-specific nav device. So Don, I apologize if I was being overly and mistakenly pedantic!
    Last edited by cstevens; 11-09-2020 at 08:10 PM.
    - Chris

    Any single boat project will always expand to encompass the set of all possible boat projects.

    Life is short. Go boating now!

  16. #16
    Join Date
    Dec 2010
    Location
    North Central Vermont
    Posts
    26

    Default Re: Advice needed for marine GPS device

    Lots of great information here from many points of view - always fascinating. thanks !

  17. #17
    Join Date
    Oct 2005
    Location
    seattle
    Posts
    20,779

    Default Re: Advice needed for marine GPS device

    Note that a nav app on a phone is way quicker than on a tablet, unless the tablet has cellular (most don’t). I had forgotten that when trying a tablet on the boat and it took me a while to realize why it was so slow to update the position.

  18. #18
    Join Date
    Feb 2006
    Location
    Pennsylvania
    Posts
    9,422

    Default Re: Advice needed for marine GPS device

    I've tried all the options mentioned above over the years. My preferred current solution is a 10" screen Samsung "Tab A" tablet running C-Map. I can recharge it from the boat's battery when needed. I keep it in a waterproof case with a clear plastic top, but most of the time it sits on the nav table inside. I don't see a need for the depth sounder -- the chart tells you where it's shallow.

    None of the options are perfect. The handheld GPSs have tiny screens and are a real pain to enter information. The phone apps have better screens than the dedicated GPS handhelds, but don't respond to wet fingers and are delicate. The big hardwired units are expensive and draw a fair bit of power. So the tablet is the best compromise I've found for a smaller boat with limited power. I have C-Map loaded on my phone, too, for backup.

    Oh - and I also always carry paper charts. They are far and away better for planning routes and just getting the big picture of the lay of things.
    -Dave

  19. #19
    Join Date
    Apr 1999
    Location
    Now, there's a long story...
    Posts
    1,699

    Default Re: Advice needed for marine GPS device

    Quote Originally Posted by cstevens View Post
    Also I think I may have misunderstood Don Z's point about "road GPS". I thought he was talking about tablet-based GPS mapping apps but in rereading the OP I realized that there was a mention of using an old road-specific nav device. So Don, I apologize if I was being overly and mistakenly pedantic!
    You weren't being overly pedantic, I was over-simplifying.

    Yes, I was referring specifically to the road based units. The GPS receiver will tell you where the device is in relation to the satellites. From there, it will convert to a lat/long. The (warning: technical term) "computer stuff" in the device (is it firmware? software that you need to do all kinds of cheetah flips to update so that it might as well be firmware? The OS? Simple black magic?) will then convert those coordinates based on the datum in the cartographic package to put you on the map. Older units are more likely to put you off, but they all can. Ever drive through a parking lot, but have the device think you're on a road? That's the cart package trying to reconcile the lat/long with the pre-programmed vector map. A boating example would be you just sailed under a bridge... and the device will have you driving on the bridge. Think of it as being "biased" toward road navigation.

    Of course, this brings up the differences between raster and vector cartography, but we'll save that for the next Oprah...
    Heute ist so ein schöne Tag...

  20. #20
    Join Date
    Nov 2014
    Location
    Seattle, WA
    Posts
    5,343

    Default Re: Advice needed for marine GPS device

    Quote Originally Posted by Don Z. View Post
    You weren't being overly pedantic, I was over-simplifying.

    Yes, I was referring specifically to the road based units. The GPS receiver will tell you where the device is in relation to the satellites. From there, it will convert to a lat/long. The (warning: technical term) "computer stuff" in the device (is it firmware? software that you need to do all kinds of cheetah flips to update so that it might as well be firmware? The OS? Simple black magic?) will then convert those coordinates based on the datum in the cartographic package to put you on the map. Older units are more likely to put you off, but they all can. Ever drive through a parking lot, but have the device think you're on a road? That's the cart package trying to reconcile the lat/long with the pre-programmed vector map. A boating example would be you just sailed under a bridge... and the device will have you driving on the bridge. Think of it as being "biased" toward road navigation.

    Of course, this brings up the differences between raster and vector cartography, but we'll save that for the next Oprah...
    Ha! Yes, "computer stuff" is probably as good a term as any. Ok then.
    - Chris

    Any single boat project will always expand to encompass the set of all possible boat projects.

    Life is short. Go boating now!

  21. #21
    Join Date
    Jan 2000
    Location
    Cushing, Maine
    Posts
    4,207

    Default Re: Advice needed for marine GPS device

    Most recent generation of tablets and phone's may be sun visible; older ones are not, at least the ones I've used. So I prefer a small dedicated unit, especially since you can get them with depth finding. I've made portable ones using lithium batteries that have run times better than tablets and phones. Thank the fishing kayak industry.
    Ben Fuller
    Ran Tan, Liten Kuhling, Tipsy, Tippy, Josef W., Merry Mouth, Imp, Macavity, Look Far, Flash and a quiver of other 'yaks.
    "Bound fast is boatless man."

  22. #22
    Join Date
    Mar 2002
    Location
    Atlanta
    Posts
    2,423

    Default Re: Advice needed for marine GPS device

    Close inshore on a boat about that size ,where there are many visible landmarks ,I'm always useing the "track up " option on my wired in GPS . That is ,the chart automatically rotates as you turn , the course made good at that moment taking the place of North -South orientation .This matches what you're seeing around you , which is most natural if you're eyeball navigating . It's just as you would use a paper chart in those conditions . Can the phone apps do that ?

  23. #23
    Join Date
    Nov 2014
    Location
    Seattle, WA
    Posts
    5,343

    Default Re: Advice needed for marine GPS device

    Quote Originally Posted by Bill Perkins View Post
    Close inshore on a boat about that size ,where there are many visible landmarks ,I'm always useing the "track up " option on my wired in GPS . That is ,the chart automatically rotates as you turn , the course made good at that moment taking the place of North -South orientation .This matches what you're seeing around you , which is most natural if you're eyeball navigating . It's just as you would use a paper chart in those conditions . Can the phone apps do that ?
    Yes, in my experience. All the ones I have used provide a course-up view option. And some, at least, provide the option to view COG as up or next waypoint as up.
    - Chris

    Any single boat project will always expand to encompass the set of all possible boat projects.

    Life is short. Go boating now!

  24. #24
    Join Date
    Oct 2007
    Location
    Southold LI, NY
    Posts
    54

    Default Re: Advice needed for marine GPS device

    Depth finder application requires mounting a transducer to a vessel that will always sit in water and a wire connection to a chartplotter or if iphones and other such devices are used a dedicated stand alone unit could be used.

  25. #25
    Join Date
    Apr 2019
    Location
    Massachusetts
    Posts
    733

    Default Re: Advice needed for marine GPS device

    My advice is a smaller low end MFD/chart plotter. They really don't pull that much power, update your position faster and more precisely, can attach depth transducer and have no problems working in a wet environment. Save the ipad for a backup.

    You can buy a brand new 7" Axiom for about $500 and it will accept C-Map, Navionics or Lighthouse maps.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •