Using new technology to save lives? Nonsense. Those people don't need what3words, helicopters, jet skis or anything else. Someone should have run to the nearest lifeboat station and the crew could have carried their rowing boat to the location by horse and cart and then launched - that's how they did it in the good old days before this unnecessary and new-fangled interwebby thingie.
If you had it you'd know that as soon as you launch the programme the 3 words that you need are clearly displayed. There's also a map, your 3x3m location is shown in a square, with an arrow leading to it, and the map confirms exactly where you are. And, if you want to be anal about it, you can press a button to show you where you are on Google earth, or press another one to show you where you are on a map - so yes, you do know exactly where you are in relation to a map, nearby features and everything else.