I am (an amateur) sailor and every time I have a new crew I go through the same set of safety rules with them including explanation of what to do in case somebo

I am (an amateur) sailor and every time I have a new crew I go through the same set of safety rules with them including explanation of what to do in case somebody falls overboard. We will usually also go through a training exercise (throw a weighted fender into water while underway) to cement the lesson a bit and for people to understand what they can expect in a real situation. Probably the most important task is that of the person who needs to keep pointing with the finger at the man over board and keep constant focus on not loosing them from their sight. On a small yacht and with any waves around you, it is almost impossible to find a bobbing human head unless somebody is constantly focused on tracking the victim. Trust me, once you loose the sight of the head that only shows in your view intermittently, it can be almost impossible to find them again. I am not a mountaineer, but I have red quite a bunch of mountain stories and the same theme repeats all over again -- people who die even though they could be easily rescued if just anybody knew where they got stuck. People who got caught by a blizzard and got disoriented even as close as a hundred feet from the basecamp. Rescuers going on a long and dangerous rescue mission even if the victim was almost at the door step. Rescuers risking their lives even though the victim have fallen from a great height and there was essentially no chance for a positive outcome. Rescuers waiting for a long time not knowing what to do and trying to weigh the risks of going out vs the risk to their friend who did not report to the base at the planned time. A simple GPS device could cut so much of that drama just like a simple mobile phone cut a lot of drama from meeting with somebody. Who still remembers the time when you had to meet with the other person at the prearranged time and if they were not there you faced a sometimes difficult decision to stay and wait because they might be late or go back home? As to the GPS receiver inaccuracy, even with inaccurate results the signal can be useful. You can usually tell if the signal is or is not accurate by how erratic it is. If it follows the planned path it probably is accurate. If suddenly strays off the planned path and then stays in one place while still transmitting -- that is very likely a sign of accident. Even if you don't have 100% certainty in the signal, rather than search everywhere for the victim and risk rescuers' lives, you can just go where the signal points and there is good likelihood you will not come emptyhanded.