Just a few points of technical clarification....
In order for the DSC feature to work on your VHF/DSC capable radio, you must have a GPS receiver interfaced with your VHF radio. I have seen a great number of VHF/DSC radios installed where the owner was not aware he needed a separate GPS input. Manufacturers are now selling both fixed and handheld VHF radios with built in GPS receivers to simplify ownership and installation.
VHF radios can be triangulated, but the only facilities capable of doing so presently are some US Coastguard facilities all located on the coast. Additionally distance from the triangulation receive site increases location error, and any fixes on an inland boat on Winnipesaukee (if two or more coastal stations could even receive such a transmission concurrently) would not only have a significant location error, but it would take a considerable amount of time and numerous inter-agency phone calls to even atempt such a fix.
Dialing 911 on your cell phone instanly transmits your location, usually accurate to within meters, to the 911 call center. This information is then instantaneously transmitted electronically and via voice to the nearest responders that would be necessary to go to your emergency. The constant inference that there are serious delays when you call 911 are again not only inaccurate, but could prove deadly if you listen to this bad advice.
The best of both worlds? Carrying both a VHF radio and a cell phone, as several astute posters here have already indicated. As mentioned a VHF radio can help you gain assistance from nearby boats also equipped with VHF radios and a cell phone can pinpoint your location if you are unsure or unable to relay it, such as after dark, in fog or bad weather or in a location unfamiliar to you.
Finally remember that at any given time you or your regular boating crew that knows how to operate the radio could be incapacitated. A boating guest unfamiliar with the radio may be hesitant or unable to operate that same radio. Something that seems natural or easy to us can be very frightening to someone who has never operated a two way radio. But virtually anyone that knows how to dial a cell phone can pick up any model and simply dial 911.
Whenever I boat, wherever I boat I always carry both a VHF radio and a cell phone....
