On a Journey to and island i would take a Blade. The blade will he useful to cut tress to make various sorts of Things such as bark to start fires and Bamboo to make beds/tools. Also the blade will help me hunt Food and cut the meat to make it edible.
On the journey i would also take Fire starters because you need a fire for various of things. With the fire you made from the fire starters you can cook food and clean water for survival. Also you can Keep warm during the cold with said fire.