If I twas stranded on a island there is one thing I would absolutley need to have. And that would be my goggles. Yes this one simple item would have to go in my survival bag. Although goggles might not even pass through anyone's mind. This was one of the first things that came to mine. Goggles would keep you alive on the island and in more than likely one case, save your behind. The island may have food or edbile plants but the ocean will always have a meal. You could always scavenge for food or animals on land but that might not always do. The ocean always has small fish or maybe even a seal. So let's be honest the chances the island is going to have animals are about as likely as you riding back to land on the back of a flying kangaroo. With goggles you can hunt for fish underwater and watch out for sharks as well. Besides over 70% of the planet is covered with water, its like an untamed zoo! Goggles would help me hunt for muscles and  oysters, all I have to do then is deal with the smell. So in the end goggles would be my friend because they would get me a meal like many other tools simply couldn't do.