I'm betting that just reading the weather forecast before leaving is an even better idea, and quite a bit cheaper than a PLB.

A little practice is useful since the forecast may off a little as to just how far a weather front will go in the next 24 hours. But it's rare for weather to appear out of nowhere so checking forecasts a couples hundred miles around their plan would likely have revealed a problem before ever getting on the boat.

I'm betting that is this case the most important part of Preparedness is Avoidance.