1. Solar Electric Boat Drive train System Design Review
MEC 440 Group o
Kanchan Bhattacharyya
Daniel Huang
Han John Tse
Ting Zhang 
Advisor: Dr. Anurag Purwar
Stony Brook University
Mechanical Engineering

2. Background
This project describes the development of a surface piercing (Arneson) drivetrain system for the annual collegiate Solar Splash Competition.
The purpose of the event is to build a single passenger solar electric boat to compete in the sprint, solar endurance, slalom, and qualifying races.
Improvements made to the current drivetrain involve changing the propeller type and speed, propeller shaft length and trim angle, motors.
The concept is a lighter, more robust surface piercing drivetrain with trim control and two different gear ratios. It takes up half of space of the previous system and is uses less parts while including more features.

3. Past Drivetrain Design
Features
Twin Motors on independent mounting plates
One shaft with two different gear ratios
Disadvantages
High center of gravity
Difficult to switch chain between gear ratios
Difficult access for maintenance and mounting
Takes up too much space
Sub optimal wiring layout (wires connect to outside of the motors, left motor wires comes from back to the front and gets close to moving chain)

4. Overview Features Twin Motors on independent mounting plates
Two different gears on each motor shaft, allowing for different gear ratios
One chain connects the three sprockets (third output sprocket not shown)
Advantages over current system
Configuration allows for two or one motors
Lower center of gravity
Ease of switching chain between gear ratios
Ease of access for maintenance and mounting

5. Overview

6. Internal Drivetrain Spring Loaded Roller Chain Tensioner
Interchangeable Gears
One or Two Motor Configurations

7. Chain Tensioner
One chain tensioner will be attached on one of the motor plates
UHMW polyethylene roller will push against the chain
Push down on the tensioner to create slack in the chain for removal

8. Mounted Bearing Shaft Assembly
Two mounted bearings support internal driveshaft
Driveshaft connected motors to the propeller shaft

9. Constant Velocity and Universal Joint

10. Detail Concept Designs (Housing Tube& Shaft)
Housing Tube & Shaft Subassembly is the exterior part of the drivetrain
Shaft is mounted through the use of two taper roller bearings at each end of the tube two support angular and axial forces
Gimbal attaches to the transom to support the assembly while providing degrees of freedom for steering and trimming

11. Detail Concept Designs (Piston Mount)
Piston mount accommodates both steering and trimming pistons
Rod ends and Clevis rod end allows for three degrees of freedom for each piston
Steering piston is connected to the steering wheel and driven manually
Trimming piston will be controlled electronically to give more precise control (trim angles will range from 0 degrees to 15 degrees)
Piston assemblies are both hydraulically driven and commercially purchased

12. Chain Tensioner

13. Detail Concept Designs (Housing Tube& Shaft)

14. Detail Concept Designs (Internal Shaft)

15. Internal Shaft Stress Analysis

16. Detail Concept Designs (Housing Tube& Shaft)

17. Transmission of Power Demonstration

18. Trimming and Steering Demonstration

19. Cost Analysis

20. Cost Analysis (Cont’d)

21. Cost Analysis (Cont’d)
Total $579.52

22. Acknowledgements Advisors University Dr. Anurag Purwar Dr. Jeff Ge
Dr. Thomas Rosati
University
Henry Honigman
Joe Schurz
Bob Martin
Department of Mechanical Engineering
CEAS
Solar Racing Team

23. Thank You