Yakski: An Electric Waterjet Propulsion System; The Effect of Gas-powered Boat Engine Emissions on Aquatic Ecosystems

Shelton, Bryce, School of Engineering and Applied Science, University of Virginia
Garner, Gavin, Mech/Aero Engr Dept, University of Virginia
Baritaud, Catherine, Engineering and Society, University of Virginia

With a growing population and the excess consumption of fossil fuels harming the ecosystem, a new technology is needed for a healthy ecosystem. To help be the voice of change, my thesis group decided to design and build an all-electric propulsion system that can be mounted on a kayak. The system is meant to provide a clean more ecofriendly system that still allows the user to traverse the waterway and enjoy nature. To know what needs to change in the boating industry to be cleaner, the STS portion of paper researched the impacts of gas-powered boat engines. The STS portion of the paper provides research on how the current gas engine technology needs to change and how it impacts aquatic ecosystems. The technical project creates a solution to the ecofriendly issue by creating an alternative system that mitigates its impact.
The whole purpose of the technical project was to create a more ecofriendly way to enjoy the waterways which will help contribute to humans having less of an impact on the environment. The project incorporated electric DC brushless motors, electric servo motors, circuit board, spin code, propeller chip, 3D printers, PLA plastic, 80-20 aluminum, and a large battery. A jet jump propulsion system was used to create less of a draft and have the boat disturb less of the water column. Each motor was connected to the circuit board and was told what to do by spin code or inputs. The whole system was powered by the large battery that is rechargeable so no gas is used.
A tough time constraint and unexpected delays led our team to rush some stages of the project and led to some failures and some success. We had limited funds and the project began to become expensive, especially the battery that would have used our entire budget alone. Also, we had limited number of 3D printers and the time to prototype and print ran longer than expected. Even with these delays, we were determined to create a prototype. The electric motors allowed the system to be ecofriendly and propel the kayak through the water. Although the kayak moved through the water, one of our goals was to reach 5 mph which was not reached, this may be due to cold temperature, wrong battery, or inability to adjust jump system depth in water. We were also able to have steering through both moving of exit nozzle and variable thrust on the system. With more time, testing, and funds electric power could be the future
The research question was the environmental impacts of gas-powered boat engine emissions on aquatic ecosystems. My thesis was from the point of view of a environmental justice perspective and support the view that gas boat engine emissions impacted the aquatic ecosystem in four main ways: air, water, noise, and soil pollution. To determine the impact, I looked at both sides of the argument; the one that agreed with my thesis and the other being that the gas engines meet environmental protection agency (EPA) standards, so they are ecofriendly. There was some research done by other universities, environmental researches, and agencies that I used to help provide data and examples for support for either side. I used a social construction of technology model to analyze the future of the technology based on the environmental needs of the stakeholders.
The research supported my thesis that gas boat engines harmed the aquatic ecosystem through four means of pollution. The chemicals released by unburned gas contributed to water, soil, and air pollution. The overall noise of the engines disrupts a fish’s ability to hunt and use its auditory senses in general. The turbulence created by a boat stirs-up sediment in the water column inhibiting sight and adds phosphorus, causing algae blooms which are detrimental to the ecosystem. Since the gas boat engine impacts the ecosystem negatively the SCOT model fails because four out of the six stakeholders need are not meet. This means that a new technology needs to be adopted or the old technology needs to be adapted.
The issue of gas boat engine impacts on aquatic ecosystem could be solved in the future with the adoption of an all-electric system. The electric system solves the environmental needs of the stakeholders but is still in the development phase. The electric system still needs to be comparable to the gas engine in other aspects like power, reliability, and cost to be a full replacement for the gas engine. With more time and research electric boats could be the future.

BS (Bachelor of Science)
Social Construction of Technology (SCOT), Electric Waterjet, Boat Chemicals

School of Engineering and Applied Sciences
Bachelor of Science in Mechanical Engineering
Technical Advisor: Gavin Garner
STS Advisor: Catherine Baritaud
Technical team members: Justin Allen, Collin Allison, Julianna Chaput, Miles Coe, David Gordon, Brian Lithen, Troy Meurer, Jonathan Ramirez

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