Iridium Go is a satellite phone system that allows you to call, text and email from anywhere in the world. It also connects with Predict Wind to download weather forecasts, perform departure planning and route planning, based on weather and ocean currents. It does this based on your boat polars (graphs of how your particular boat sails best in all winds and wind directions).
As such, I believe it is, now, an indispensable piece of safety gear for offshore passages.
An Automatic Information System (AIS) is mandatory on most commercial vessels. It provides tracking information for any vessel around you, which has it turned on. Thus, you can “see” vessels a few miles away, their heading, speed, name, details and their boat equivalent of a cellular phone, on which you can call and talk to them. They are becoming increasingly popular on sailing and fishing vessels.
The more advanced ones, like the new Vesper Cortex, also incorporate anchor dragging warnings, sensor alerts (high bilge water, etc.). The Cortex also comes with a wifi system to allow you to view everything on multiple Ipads and cellphones.
Again, having used a similar system on many sailing adventures, I believe this is also a key safety feature, especially in busy marine areas, or when sailing at night near any commercial vessel.
With each of these, it is great to have a Crew member who knows a thing or two about electronics, and has the time to head to the boat in advance for installation and testing. 🙂