Based on the technical nature of the material, which focuses on hull efficiency, electric propulsion, and endurance testing, the ideal group to review this topic would be Naval Architects and Marine Systems Engineers specializing in Electric Propulsion.
As a Senior Marine Systems Engineer, I have synthesized the data from the endurance trial of the 14-foot carbon fiber catamaran below.
Abstract
This technical assessment documents a 66.7 km range test of a custom-built 14-foot carbon fiber micro-catamaran on Lake Washington. The objective was to evaluate the efficiency of a high-aspect-ratio displacement hull against previous benchmarks set by a 13-foot Boston Whaler (a planing hull). Utilizing a dual-motor electric drive and a Voyage Systems telemetry logger, the test yielded a mean efficiency of 19.4 Wh/km at an average speed of 5.3 knots. The findings confirm that the catamaran's long, narrow hulls significantly mitigate wave-making resistance, allowing it to exceed theoretical hull speed with minimal power penalties. Despite performance gains, the vessel exhibited low reserve buoyancy in choppy conditions, suggesting a need for increased freeboard in future iterations.
Endurance Trial and Performance Analysis
0:00 Comparative Analysis Objective: The trial aims to surpass the 50-mile mark established by a 13-foot Boston Whaler. The hypothesis posits that the catamaran’s displacement-optimized hull will offer superior efficiency over the Whaler’s stability-focused planing hull at low speeds.
1:16 Initial Propulsion Metrics: The vessel is operated via joystick steering with a target cruise speed. Initial telemetry indicates a speed of 10 km/h (approx. 5.4 knots) with an estimated runtime of 9 hours based on current battery state of charge (SoC).
2:50 Data Logging and Instantaneous Efficiency: Real-time data logging via the Megan/Voyage Systems unit shows an instantaneous efficiency of 16.7 Wh/km. The system monitors VESC (Variable Electronic Speed Controller) data to ensure precise power management.
5:28 Environmental and Hydrographic Constraints: Navigation through river deltas and shallow sectors introduces risks of biofouling (seaweed) and propellor cavitation/damage. High-density schools of fish and "gas bubbling" from the lakebed are noted during transit.
8:05 Hull Speed and Wave Piercing Observations: The vessel maintains 11 km/h (approx. 5.9 knots), exceeding its theoretical hull speed. Due to the high length-to-beam ratio of the hulls, the catamaran avoids the steep "drag wall" typical of wider displacement vessels. However, the narrow bows tend to pitch-pole or "dive" into oncoming wakes due to insufficient forward buoyancy.
11:06 Power Scaling: Throttling up to 300W per motor (600W total) maintains a consistent 11 km/h. The operator utilizes an umbrella for thermal management (bi-mini substitute) in low-wind conditions.
12:45 Efficiency vs. Velocity Trade-offs: A critical observation shows that reducing speed to 7 km/h nearly doubles the estimated runtime to 15 hours. This highlights the non-linear relationship between speed and power consumption in marine environments.
14:26 High-Power Sprint and Final Dash: At 42% SoC, the power is increased to 1,000W total, achieving a maximum speed of 18 km/h (approx. 9.7 knots). This "chooch" phase demonstrates the vessel's capability to operate in a semi-planing or high-speed displacement mode at the cost of rapid battery depletion.
15:53 Structural and Hydrodynamic Conclusions: The catamaran is found to be 12 times more efficient than the Boston Whaler when normalized for speed. Key takeaways include the necessity for taller hulls (increased amas/outriggers) to improve sea-keeping in rough water and the potential for a solar-powered trimaran configuration for multi-day voyages.