WHAT IMPORTANT THING DOES PI START TO DO AT THE END OF CHAPTER 50?

It the end of Chapter 50, Pi starts to identify certain things around him that he can make use of.... things that will serve to save his life.

I did not grasp all these details-and many more-right away. They came to my notice with time and as a result of necessity. I would be in the direst of dire straits, facing a bleak future, when some small thing, some detail, would transform itself and appear in my mind in a new light. It would no longer be the small thing it was before, but the most important thing in the world, the thing that would save my life. This happened time and again. How true it is that necessity is the mother of invention, how very true.