For surface running, "A13" was powered by a single vertical, six-cylinder Hornsby-Akroyd oil engine that drove one propeller shaft. When submerged the propeller was driven by a electric motor. They could reach on the surface and underwater. The heavy oil engine was heavier than the petrol engines used by the other boats in the class and an equal amount of fuel had to be removed, which reduced their range despite the heavy oil engine's more economical consumption. On the surface, the boat had a range of about at ; submerged the boat had a range of at .