The gyroboats in the film are built with Bensen rigs.
The concept has a couple serious problems, both related to the aerodynamics of the boat.
First, the fuselage is clearly unstable in yaw and pitch. There's more hull area ahead of the CG than behind it. As result the craft will very abruptly yaw stern-first if the towline either breaks or is deliberately released in flight. It may also "pitchpole" (do a forward somersault) under the same conditions, for the same reason. In today's gyro parlance, the latter form of instability is called drag-over (contrasted with pushover).
Second, even with the towline still attached and pulling, the craft will do an uncommanded, abrupt dive if it first climbs high enough that the bow dips low and the relative wind enters the open hull from above. This famously happened to Igor Bensen once when he was flying a gyroboat in front of a crowd. Fortunately, the gyroboat leveled out in response to the towline pull once it neared the water. This aerodynamic effect is powerful enough to overcome the control power of the rotor. A friend of mine had the same experience, but in a powered gyro with floats. He didn't level out of his dive, despite back stick. Instead, he plowed nose-down into Long Island Sound. He got rather badly hurt.
It's possible to make even a Porta-Potty (outdoor toilet) stable with enough tail surface power. The necessary tail area and leverage are hard to achieve within the small triangular space available at the back end of a gyro, though.
