Ocean passages—whether racing across the Pacific, cruising to the Caribbean, or crossing the Atlantic—carry inherent risks. One of the more common, very serious, but least planned for threats is losing power and communications, which can be critical to navigate safely and stay in touch with the outside world.
Modern offshore boats are packed with electronics: GPS receivers, chartplotters, satellite communications, and onboard networks. Yet all these depend on a functioning power generation and storage system. An engine-mounted alternator, solar panels, wind turbines, or hydro generators can all fail due to mechanical breakdowns, storms, or lightning strikes.
Once you lose main power, you have:
- No GPS for accurate position fixing, needing to rely on celestial navigation (if this skill is even present on the boat)
- No electronic means to communicate during distress other than an EPIRB
- Limited or no way to receive updated weather forecasts
This can quickly escalate a situation that is merely inconvenient to one that is life-threatening. In just the last 15 years there have been dozens of high profile cases of boats losing power, with some boats adrift for weeks before being rescued, or others that resulted in unnecessary SAR operations when they failed to arrive as expected.
There have also been numerous recent examples of boats not having a backup form of data & communication, for example only having a Starlink system and no redundant methods to communicate should the system fail. While not as serious as a total loss of power, this can also be quite disruptive and often result in the end of a race or unnecessary resources being deployed.
Here is a small kit we've put together that is a fully self contained "power and comms in a box" emergency communications and navigation package.
Container
We used this Mission Darkness 15L dry bag / faraday cage combo with added foam in the interior to ensure flotation. The faraday cage and exterior insulation will protect your electronics in a lightning strike, while the dry bag will protect them from water damage.
Power Generation & Storage
We used this foldable 56W solar panel, and a 100W / 30Ah laptop power bank that would be able to fast charge from the solar panels and store the power for later usage. Make sure the solar panels and power bank use the same charging standard, ideally a newer one that can deliver more power. The 100W power bank has enough output to charge the boat laptop, with a spare laptop battery included as well.
Cables, cables and more cables
Make sure you have any and all cables that you need to charge various devices. We included a long USB-C cable to connect on deck solar panels to a more sheltered power bank, as well as a Toughbook battery charger that runs off of 12V/USB-C. Separately, we also purchased a fused 12V Toughbook laptop charger, in the hope that a lightning strike might eliminate the charger but not reach the laptop itself.
Communications
This is where the budget could start getting tight as these devices are not known for being cheap. We included a spare Garmin inReach, a spare Iridium Go that one of the crew had on hand, a spare pre-paid Iridium Go SIM, an external laptop GPS antenna, and an old iPhone pre-loaded with offline navigational charts. We also had a handheld floating VHF radio in our standard go bag.
With this emergency communications kit, we had a fair amount of certainty that—absent the unlikely loss of GPS and communications satellites—we would continue to be able to get a GPS fix, navigate, receive weather, and continue on our way without much disruption. We did have a borrowed sextant onboard and a crew member capable of using it, which would serve as a last resort.
As with any emergency precautions, it's helpful to drill using your kit at least once to make sure you aren't missing any critical cables, and to make sure all of the equipment in the bag functions as expected together.
To my knowledge, unlike many other potential emergencies at sea that are well discussed and with documented standards to prepare, the loss of power and communications is paid much less attention. All comments and feedback would be most welcome.