A word on power packs from Race Chief, Dylan:
"Power packs need to be kept in a 100% sealed, waterproof bag or container, triple sealed if need be.
The tracker if fully charged will last a full day so there is no need to charge it while at sea.
Solar power chargers are improving each year but make sure you get a good one, the cheap ones are pretty much useless. Bear in mind that most daylight hours will be spent at sea so make use of every opportunity to change your power pack and your tracker.
I use a 10 000mA power pack that charges the tracker 3 times over if fully charged itself."