Learning the HARD way...
Join Date: Jan 2007
Location: Boston / Ft Myers Area
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In the hope of addressing some confusion, here is my experience from owning a GPSmap 478 (non-touchscreen predecessor of the GPSmap 640);
The unit includes ALL the US Costal Charts in ROM. It also includes US road maps (in great detail) in ROM. Also included in the box is a Bluechart basemap DVD. This DVD includes all the current detailed Garmin charts. However, you need an unlock code to enable each specific region. You really cannot do coastal route planning on your PC with the included software license. The basic chart that the license unlocks does not provide ATON for harbors or channels.
Garmin makes a lot of money (I suspect the majority) selling charts. Think of these chart plotters as razors, and the charts (and updates) as razor blades.
As SD pointed out, you can update the included charts for an area by buying a Garmin chart (on a Garmin memory card) for that area (~$160), loading the updated chart into the unit, and returning the card to Garmin. Garmin will refund $70 (I believe), so that your net cost of updating ONE area is ~$90. I have not done so - yet.
There are some models of Garmin chart plotters for which a lifetime (of the product - as defined by Garmin) update of the included charts is available for ~$130.00 Neither the GPSmap 478, not the 640 qualify for this update service.
That said, I LOVE my GPSmap 478! I bought it when it first came out (2006) for about $950. Because I sail on OPB, this is the one chart plotter that I know what ALL the buttons do. I find that it has more, and better features than most of the chart plotters that are installed on the boats that I am sailing. I have also benefitted that in the event of an on board electrical failure (this happened) the GPSmap continues to function. Should I ever have to ditch, I can carry this unit with me.
Regarding the comparison to automotive GPS units, I find that the display of the GPSmap gives far more useful data than the built-in unit of my wife's 2009 Hundai Azera. I configured the data fields to show me actual speed (I know that my speedometer consistently reads 3mph faster than actual), ETE Next Turn, Distance Next Turn, and ETA. All of these fields are user selectable from about 80 different telemetry calculations. When I used to travel extensively for work, this unit was always with me, and was worth the price in lack of frustration in finding (or getting close to) customer sites.
Occasionally, the unit would screw up in finding a specific address, or the BEST route to my destination. For example, every time that I travel to my sister's condo in South Ft Myers, FL, from the north, it directs me to get off RT 75 in FT Myers, and travel route 41 South through all the stoplights. I ignore the unit, and get off 75 two exits south of the original directions. This is what I would call "local knowledge."
To me, the difference between the 478 and 640 is that the 640 has a larger TOUCH screen, and that the unit will automatically switch between Auto and Marine mode (I do not like this, as I will sometimes look at a mooring field, or canal, from my car and wonder what the draft is. I simply switch to Marine mode, and have my answer. I'm not sure that youcan do this with the 640).
As for water resistance, I can vouch that my 478 was exposed to about 5 hours of road spray while mounted on my motorcycle, travelling through torrential rain, on my way from Key West to St George SC. This did not affect the unit, or it's connector at all.
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USCG Licensed OUPV Captain, ASA 101/103/104/105/106/118 Certified Instructor - Also certified in Recreational Marine Electrical Systems
Last edited by eherlihy; 10-11-2009 at 01:51 PM.