Like the magnetic compass, which is kind of crucial if you like to know where you're going, came from China. Muslim sailors popularized the astrolabe, which made it easier to navigate by the stars. And boats using sternpost rudders were easier to steer, so that technology quickly spread throughout the monsoon marketplace. The Islamic world also produced the triangular latin sail, which became super important because it allowed ships to tack against the wind. This meant that a skilled crew could make their way through the ocean even if they didn't have a strong tailwind. And just as with the Silk Road, ideas also traveled in the monsoon marketplace. For instance, today, more Muslims live in Indonesia than in any other country.