The Weekend Navigator Part II Copyright 2008 Coast Guard Auxiliary Association, Inc.

Chapter 9: Underway With Digital Charts

Displaying chart information directly on a Chart Screen is ideal –Digital charts are easier, but more expensive –Computers are best suited for enclosed helms –Chartplotters are more appropriate for smaller boat (<18 ft.) with exposed helms

Using a Chartplotter Underway Chartplotter – a custom display and processing unit programmed to present live position information on a digital representation of a chart May include a GPS, built-in or remote antenna, and receive input from external GPS receiver

Using a Chartplotter Underway Most chartplotters use vector charts Display your current position, active leg or route, and stored waypoints The accuracy of the chart is limited to the accuracy of the source chart at its original scale. Over zooming can give you a false sense of security

Using a Chartplotter Underway Most chartplotters permit the user to select the amount of detail that will displayed –Too much detail can be confusing –Underway, the simpler the better Chartplotters operate in two modes: –Planning –Navigation

Using a Chartplotter Underway Many chartplotters are permanently mounted Waypoint data can be uploaded from a computer directly into the chart plotter Large screen and buttons make chartplotters easier to use than hand-held GPS units

Using a Chartplotter Underway Chart screen –Local channels and harbors show the least amount of preprinted chart detail Open water –The Chart Screen can point out hazards –Plot your position on a paper chart every hour just in case electronics fail

Using a Chartplotter Underway Planning on the fly –Your mission is to plot your new course on a chart and to avoid any potential obstacles

Using a Chartplotter Underway Highway screen –Has more detail and resolution than GPS Celestial and tide data –Provide information on rising and setting times of the moon and times of high and low tides at the cursor location

Using a Computer and GPS Underway Marine environment is harsh on computers Display brightness can be an issue Much more functional for long trips

Using a Computer and GPS Underway Navigation software –More versatile than chart plotters Navigation software versus planning software –Can accept and plot GPS positions on the screen

Using a Computer and GPS Underway Navigation computer display information –Nautical chart is the heart of the display Monitoring and planning with navigation software –Can call upon a variety of alarms (i.e. anchor, avoidance, off course), note features, and man overboard features

PDAs and Pocket PCs Can be equipped for live navigation with GPS Essentially programmable computers that use GPS and digital charts for navigation Small size has pros and cons

The Future of Onboard Computers Maptech i3 may be the system of the future Currently too expensive for recreational boaters