Beginning in 1988, we began taking a small electronic beacon, commonly found in airplanes that would alert authorities if we had an emergency. It was called an ELT (Emergency Locating Transmitter). In 1995 we replaced it with the new generation of such devices called an EPIRB (Emergency Positioning Indicating Radio Beacon). This was about twice the size of the small walkie-talkie -- like the ELT.
Our EPIRB (a Satellite 406 unit uses satellite technology, specifically the COSPAS-SARSAT) to track the signal and alert appropriate emergency response team. The unit cost about $1,200 and it is registered with the Canadian Coast Guard, who send us stickers to update it. We will have it along again -- really, a backup if both satphones fail. These EPIRBs help reassure our wives and loved ones when we venture out on these seemingly perilous journeys.
The unit is manually deployable, in other words we have to pull a pin. The other units available are unsuited for our purposes since they activate upon contact with water (kind of unavoidable on a canoe trip) or after a high-speed impact (I don't even want to think about how something like that could happen!).