The broader impact of this Small Business Innovation Research (SBIR) Phase I project is to reduce pollution and noise in and on waterways for the recreational boating market, and provide a silent, reliable alternative for search and rescue operations, defense, and law enforcement. The project will result in an important prototype outboard motor designed as an electric marine propulsion system from inception. This project will double the cruising range of current commercial electric outboard motors, thereby matching gasoline-power engines in terms of range, while resulting in less than half the ten-year cost of ownership. This has important environmental benefits as well. This Small Business Innovation Research (SBIR) Phase I project aims to provide a competitive electric outboard motor and battery system for boats up to 25 ft in length which will match the range of gasoline engines, while mostly eliminating maintenance costs. Four development trajectories are being pursued: (1) replacing shaft-and-bevel gear systems with modern transmission materials to reduce noise and improve efficiency, (2) improving propeller thrust by adopting a larger and redesigned propeller enabled by electric motors running more efficiently at low revolutions per minute, and optimizing fluid dynamics properties of the assembly, (3) developing a cooling system that avoids sea water ingestion to reduce maintenance effort and cost, and (4) adapting batteries with more flexible form factors and optimizing the battery control system to maximize cruising range. Technical requirements and challenges include: (A) demonstrating that the durability of the new drive materials exceeds existing gear drives; (B) predicting fluid dynamics, and the successful interplay between computational modeling and tank testing; (C) designing a completely sealed cooling system, which will neither leak during the lifetime of the motor, nor overheat even during peak operation, and (D) understanding the complex interplay between motor and battery control systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
