Well, there’s already some excellent suggestions...
...but there really is only one watch that ticks all the boxes; indeed, it could have been designed for just this situation. The Rolex Explorer 1016. This one’s my son’s (but he lets me wear and enjoy it).
Perfect for a castaway. Tough and rugged, waterproof, luminous and it won’t let you down. Also, when rescued, whatever the rigours of 28 years desert island living have done to your appearance and clothing, you’ll still look cool with this on your wrist. Regards Kev.