The Cyclor Revolution: Tactical Power Dynamics in AC37

The Shift to Leg-Driven Hydraulics

The reintroduction of cyclors for AC37 represents a fundamental pivot in how AC75 yachts generate the pressure required for high-performance sailing. While the wind provides propulsion and batteries manage foil adjustment, the cyclors provide the raw energy for sail trimming. This transition from hand grinding to leg power isn't just about aesthetics; it is a clinical decision based on the superior muscle capacity of the human lower body. By utilizing larger muscle groups, teams aim to maintain higher sustained pressure in the hydraulic accumulators, ensuring that every trim adjustment is immediate and precise.

Energy Accumulation and System Design

The core of this tactical evolution lies in the hydraulic accumulator. This chamber uses compressed gas to store energy generated by the cyclors' rotary motion. In America's Cup racing, the ability to store and release energy efficiently determines a crew's agility. However, new rules have standardized these pumps and accumulators, removing the ability to change gears during a race. This creates a strategic bottleneck. Teams like INEOS Britannia previously used mechanical advantages to free up crew members for tactical roles, but the current constraints demand a more focused, high-output power squad.

The Zero-Momentum Problem

A critical pitfall facing these athletes is the lack of momentum. Unlike road cycling, where a bike's forward motion and flywheels help carry a rider through "dead spots" in the pedal stroke, pumping oil into a hydraulic system provides constant, dead resistance. It is like riding a home trainer with no flywheel; the resistance is unrelenting. Cyclors who train exclusively on the road may find their power numbers plummet when faced with the viscous reality of pumping oil. Success requires specific physiological adaptation to high-torque, low-inertia environments.

Optimizing the Power Stroke

To overcome the dead spot, teams must explore mechanical and collaborative workarounds. Linking multiple riders to a single drive shaft with offset cranks allows one teammate to provide power while the other is in their weakest phase of rotation. Furthermore, the potential use of Osymetric or oval chainrings offers a mechanical advantage by varying the lever length throughout the stroke. If the rules permit these variations in angular speed, it could be the margin between a sluggish trim and a winning maneuver in the final leg.