GPS Options by Marc Bastin

Club Member Marc Bastin writes about the Garmin GPS units at this year's boat show (Magellan was not represented - so no info there)...

The cheapest option is the eTrex 20 plus an electronic chart for all of the USA and British Columbia.  (An eTrex 30 would add barometer and compass, which are not necessary for sailing but might be nice for hiking.)  It should last up to 25 hours on 2 AA batteries according to the brochure.  The rep at the booth said 20.  It has a mini-joystick interface and a display of only 2.2" diagonal with 128 x 160 pixels and 65k colors.  It is IPX7 submersible (one meter deep for 30 minutes).

The better option is a GPSMAP 78 plus the chart.  (The 78s adds a barometer and 3-axis compass, and the 78sc also preloads a "coastal US chart" but I'm not sure if that also covers Alaska, Hawaii, and British Columbia as the add-on chart would.)  The 78 is specifically targeted to the marine market and is WAAS enabled for better accuracy.  WAAS is a system of land based transmitters that complement the GPS signals from space.  The brochure says two AA batteries should last "up to 20 hours."  It has a pushbutton interface and a much better display of 2.6" diagonal with 160 x 240 pixels and 65k colors.  It's not only IPX7 submersible but also floats!

The eTrex range wasn't available at the show and I didn't have the time to play with the GPSMAP 78, but according to the rep, both are very, very similar: they have an audible anchor drag alarm but it isn't super loud, tide and current data (once you load the micro SD marine chart), COG vector, and MOB even though this might be somewhat buried in the menus and not as readily accessible as you might wish.  The rep said the displays are sunlight readable but I have some doubts about the quality.  Obviously I couldn't take it outdoors to test it.  None of the units can charge their two AA batteries, but if you get the car kit and run them from the boat's battery they will preserve the charge of their internal AA batteries.

Ultimately, the main difference is the number of pixels and WAAS, which make the GPSMAP 78 the clear winner since I found it online for only $30 more than the eTrex 20.  

Here are the prices at http://starmarinedepot.com.  You may have better luck elsewhere, I didn't push very hard to find the best deals.  There are no boat show specials.

   eTrex 20: $180

   GPSMAP 78: $208

   HXUS039R g2 "Entire US" (micro SD chart): $124 (You'd have to add this to either GPS unit.)

The eTrex 30, and GPSMAP 78s and 78sc are far more pricy.

Regarding smartphones and tablets, there's one more app that I didn't point out last time.  It is called iNavX and runs on iOS and Android.  The app plus charts for the US and Canada would set you back about $70, which is why I didn't mention it.  It's the app with apparently the most features, but Navionics is allegedly far more user friendly and is only $15.  I haven't had any hands-on time with either.  The rep at the Navionics booth told me they were working on weather integration so I presume in a future update it will be able to overlay GRIB weather forecasts as well.  (Navionics typically charges full price for upgrades of their app and doesn't do discounts.  If you buy it now you'll probably have to buy it again later without discount if you want the new functionality.  You would also update your charts in the process and the price is amazingly low so it's not too bad a deal.)

Please keep in mind that your smartphone will receive a trashing in the marine environment, and if you have to replace it every 3 months it's a false economy compared to buying a dedicated waterproof device.  I had an iPod Touch on my 43 day trip to British Columbia last spring and the connector corroded in that little time.  Corrosion isn't covered by Apple's warranty but after showing how displeased I was with that they still replaced the unit.  Next time I'll keep it in a ziplock bag at all times, perhaps with a dehumidifier baggy.  My portable Raymarine RC400 chart plotter on the other hand has been going strong since 2005 with 5 years at sea and 20,000 nautical miles under its belt, in full (tropical) sunlight, rain, and spray.  In other words it has already worked outdoors for over 4,000 hours.  It has a slowly increasing number of dead pixels but is otherwise still fully functional.