A plus for Navionics is its automatic display of buoy numbers; C-Map has to be set up by the user to show this information. "It's a nuisance to chase that down," says Spear. Navionics identifies buoys and anchorage areas that aren't identified at first glance on the C-Map display. In either case, with C-Map or Navionics, if you're in doubt about what aid to navigation you're approaching, put the cursor on the object and it will be identified in an information window at the top of the screen.
C-Map has some color problems, too. The dumping-ground buoy is the wrong color, and the sector circles for the navigation lights, which are yellow on the C-Map display, should be white (which is the color you would see at night). Again, you can put the cursor on the dumping-ground buoy and the information window at the top of the screen provides a description. It's just that it takes more time and manipulation to get the information that way, when you should be able to tell just by looking at the screen.
ACCURACY
When there's limited visibility, and there are shipping lanes nearby, you don't want to find yourself compressed under the bow of a freighter or tanker. Thus, it's a good idea to know exactly where you are in relation to those lanes. On the C-Map chart, shipping lanes show up as two parallel lines with dots between them on the four-mile scale. At the same scale, the shipping lanes on the Navionics chart use two parallel red lines to show their location. The effect at that scale is that you can see and find things more readily on the C-Map chart if your attention is divided.
Switch to other scales on C-Map, however, and the shipping lane is marked only by a single line that represents the middle of the lane. This gives the advantage to Navionics, explains Bernstein, who favors the two-mile scale when following a tanker out of the bay. "I use the Navionics chart to do my approach to a ship because I get the double line on the traffic lane, which is more useful to me. That's because before I make my approach I want to keep to the edge of the traffic lane because the ship is in the center of the lane."
IDENTIFICATION
Although there are some times when C-Map doesn't display the same data found on a Navionics chart for Penobscot Bay, overall, C-Map shows far more data than Navionics. That's true for the names of islands and mainland locations as well as for potential navigational hazards. For instance, the Rockland breakwater is identified on C-Map, but you have to put the cursor on the breakwater shown on the Navionics display to have it identified. C-Map also has far more depth markings than Navionics. On one level, all of C-Map's information is helpful, showing the identity of various islands, coves, and harbors, but at the same time, it can be confusing because a lot of information, displayed in a number of different colors, gets jammed onto a small screen. In addition, the C-Map chart of Penobscot Bay left out information in a couple of places where the electronic chart was built from two differently scaled government charts that abut each other, and the digitizing process used to make up the electronic charts didn't compensate for the change in scale ranges. The information for the area that's blank on one scale can be obtained by zooming to another C-Map scale. Navionics provides enough information to be usable without having to zoom in or out.
For instance, in the Fox Island Thoroughfare, the passage between North Haven and Vinalhaven Islands, using the four-mile scale, C-Map shows a blank area without depth marks or contour lines. At the same scale, Navionics shows some depth marks, contour lines, and has a buoy you can set a course to. To get navigating information on the C-Map chart, you have to zoom down to two miles. Some people may find shooting courses by way of the cursor easier on the Navionics chart because they won't have to zoom in to find their next waypoint.
ADJUSTMENTS
Though C-Map's richness in detail can get in the way, any confusion can be avoided by taking advantage of vector charting. To customize the data you want to see and add or delete layers of information, go to the menu, find the appropriate file, and then remove from the screen enough information to make the display less confusing or add information when needed.
Both the C-Map and Navionics menus are easy to use and about equally fast at accessing information. If you want to remove all depth markings other than those less than 10 meters, for example, go to the menu, call up the contour line file, and turn off all depths except ones less than 10 meters. The same can be done for other types of information displayed on the chart, such as text, sectors, or background colors.
C-Map and Navionics operate at about the same speed when working among menu pages, but C-Map is much slower than Navionics when going from one scale level to another. It might be because there's more information to process, but C-Map often takes six to eight seconds to do a screen redraw when going from one level to another; Navionics does it in about a second. Because the Navionics screen changes so quickly, it's easy to miss the scale level as it flashes on the screen. One point of contention here: Everyone thinks the scale level should be displayed onscreen at all times on both programs.
EXTRAS
Both C-Map and Navionics have port service information directories, which list the various services available at harbors in the area, such as gas, diesel, ice, and water. An icon appears for each service. Put the cursor on the icon, hit enter, and you're shown what's available and where. We tested this for Rockland, and C-Map's listings were more extensive. In one case, Navionics didn't list a major marina.
PRICE AND UPDATING
Depending on how much area you want your electronic chart cartridge to cover determines how much you'll pay for charts from either company. Both C-Map and Navionics offer three levels of coverage. Each level nearly doubles the amount of coverage as the previous level. C-Map's prices run $99, $199, and $349. Navionics is priced at $99, $199, and $299. To update a Navionics chart, you'll get 75 percent off the sticker price if the chart coverage doesn't change. Otherwise it's a 50 percent discount. C-Map NT charts can be updated and the older CF85 can be updated to C-Map NT. C-Map says that the pricing varies but it's less than the original purchase price. You'll be notified of C-Map updates if you register when you buy a cartridge.
THE WINNER
So, which is the better electronic chart? After a poll taken among our group, C-Map gets the thumbs up - and this from Penobscot Bay's professional seamen who are used to dealing with electronic equipment and navigation problems. C-Map charts provide more information and the color contrasts make it easier to tell what you are looking at, despite its slow redraw time.
At the same time, Navionics might be just the thing for the boater who doesn't feel comfortable fiddling around with electronic equipment. For that buyer, the fewer adjustments required the better. And if he cruises one area often, he'll quickly get used to the Navionics cartography and how it corresponds to his area.
