Navigation Requirements Statement

Current situation:

I need a new GPS and electronic charts - used to having cmap nt charts and standard horizon chartplotter.

cmap nt charts for all of east coast and caribbean and canada $225 (does this include bermuda?)http://www.landfallnavigation.com/cmapntplus.html

Likely replacement: Standard Horizon cp 180 (~$400). Not the best, but good. Biggest complaint is the inability to dim to low enough levels.

Alternative, smaller Garmin unit 540?

I would like to have PC charting ability also, both for planning and for below deck large screen inspection of charts. Used to navigator from Maptech.com. I have free version now. 3 versions available from $180 - $600. Has the ability to push routes into the standard horizon (and I assume, Garmin) chartplotters, but cannot read their charts.

Maptech uses NOAA charts (free) but they do not include Caribbean, nor Bermuda, can we get compatible format maps for these locations?

There is a PC Planner for cmap nt http://www.landfallnav.com/ecmnt.html for similar money to maptech software, good for Standard Horizon only, not Garmin. Garmin does not have similar product according to http://www.panbo.com/archives/2007/03/ideal_marine_electronics_mac_mini_version.html

Also: should we get AIS box to be able to tell when there are ships in vicinity? ~$180. http://www.milltechmarine.com/products.htm Does this require a new antenna? other purchases? is the power consumption an issue (>1 amp would be an issue)