The twin engines supplied by the Rennies each had two 37-inch cylinders with a three-foot stroke, delivering a combined nominal horsepower of about 80, and an actual horsepower of about 60. The engines ran at 26 rpm, which through gearing drove the propeller shaft at about 140 rpm.[17] The boilers operated at a pressure of 6 psi. The engines were installed in early 1839, following the ship's launch in October 1838.