Complex sentence: These "fender chains" featured elaborate braking mechanisms to allow a ship of up to 10,000 tons to be safely stopped, but given the precise control of ships made possible by the mules, it was very unlikely that these chains would ever be required.
Split into simpler sentences: These "fender chains" featured elaborate braking mechanisms to allow a ship of up to 10,000 tons to be safely stopped. However, given the precise control of ships made possible by the mules, it was very unlikely that these chains would ever be required.