I should also mention:
The NAVIONIC'S Mirco-SD cards you buy to insert into a Fish-finder/Chart Plotter typically cost about $150-$300. Very expensive.
If you choose to download the Navionics APP on your iPhone, iPad, or Smart Phone, the cost for the very same level of accuracy (and the added benefit of it being portable vs attached to your boat) can be had for as little as $10.00.
iPad HD Version $49.99
"Boating HD" With NAVIONICS+ HD -
The best version in terms of resolution and detail, but requires an iPad and expensive in-app purchases.
https://itunes.apple.com/us/app/boating-hd-marine-lakes/id744966613?mt=8
iPhone Version $10 (annually), with in-App purchases for USA lakes etc. in higher detail with Navionics+ ($4.99 annually)
"Boating USA" is basic, detailed marine maps, including Lake Powell in pretty damn good detail. Although the iPad version is better (above) I honestly use the iPhone version almost all the time because the non-HD version works well, and is easily viewed and used on my phone. You can save routes, mark spots and share them with others, etc. So with the Navionics+ in-app purchase for $4.99 it does just about everything you'd want for quality navigation. The maps obviously work even when you are NOT on a wireless or cellular network, as long as you mount your phone in a place with line-of site to the sky so it can acquire and track GPS coordinates.
https://itunes.apple.com/us/app/boating-usa/id377908737?mt=8
With the iPad, iPhone, and Smart Phone versions of Navionics, the internal GPS in your phone (or iPad if you have the cellular version) is supported even when in the middle of nowhere. THAT SAID, the GPS antennas on the phones are small, and susceptible to interference occasionally. Because of that, I use a supplemental GPS unit made by Garmin (not waterproof) which connects to my phone/iPad via bluetooth. This enables the app to leverage the much more accurate external GPS (including Russian GLONAS) giving you much more accurate readings down to the foot, and speeds accurately shown in MPH updated 6 times per second.
The external GPS unit is this: Garmin GLO
- Needs to be mounted under the windshield so it doesn't get wet or rained on (can be simply velcro'd on, just make sure it's protected from water and has sky view)
- Has a built-in lithium ion battery that lasts about 2 days on a full charge. It also has a USB port for charging and can be used while charging
https://www.amazon.com/gp/product/B00AYAZENY/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
I mount the GPS using a suction cup "phone holder" by squeezing the GPS between the phone holder clip. MUST NOT BE MAGNETIC
https://www.amazon.com/Macally-Wind...=1-1-spons&keywords=phone+mount+suction&psc=1
I mount my phone on the dashboard using a magnetic mount like this one on Amazon: (requires an included small metal plate to be adhered to your phone or case)
https://www.amazon.com/Scosche-MAGW...519765692&sr=1-8&keywords=phone+mount+suction
Keep in mind, using the magnetic mount
does slightly interfere with the internal phone GPS (it still ID's GPS coordinates via RF Mhz, but it doesn't recognize compass heading changes), so I usually use it paired to the Garmin GLO when navigating to ensure I have both GPS and Compass headings updated and accurate in real-time.
Overall the entire setup with phone holder, GPS unit, GPS holder, and Navionics App, you're in it for about $150. But to me, having it on my phone and mobile vs shackled to the boat is more than worth it.
If you use a non-magnetic mount for your phone, eliminate the external GPS, and just use your cell phone GPS and the App, you're looking at about $30 all-in, and gives you a pretty darn useful set of tools to map, track, save and create routes, etc. And even with the internal GPS as long as you keep the phone in a non-magnetic spot and where it can see the sky, you'll probably have everything you'll ever need.
