Could Surcouf hunt unescorted merchant ships?

Even unescorted prey was difficult to find because the reconnaissance aircraft forced Surcouf to expose herself, advertise a recovery point, and spend time assembling and handling the aircraft.

Question

Could Surcouf use its guns and aircraft to hunt unescorted merchant ships?

Short answer

That was the theory, but finding and recovering the scout aircraft exposed the submarine and limited its movement, while surface cruising risked detection before it could close the target.

Notes

Unescorted shipping was the intended target, but the submarine still had to locate it across an ocean. Launching the aircraft required Surcouf to surface, assemble the machine, and either remain near a known position or transmit a signal that helped the pilot find the boat again. Currents could move the submarine away from the planned recovery point, and disassembly after recovery prolonged the exposure. Cruising on the surface without the aircraft was also slow enough that independent merchantmen might escape or report the raider. The scouting system therefore weakened the concealment and freedom of movement that were supposed to justify a cruiser submarine.