Promoting Electric Propulsion (PEP)

Promoting Electric Propulsion (PEP) is a collegiate engineering competition, sponsored by the American Society of Naval Engineers (ASNE), that challenges students to design and build high-performance electric watercraft. The initiative focuses on advancing sustainable maritime technology by tasking teams with optimizing battery systems, motor efficiency, and hull hydrodynamics to achieve maximum speed and endurance. Beyond the race itself, PEP serves as a hands-on workforce development program, preparing future engineers to solve complex systems-integration problems in the growing field of electric marine transportation.

RCCF has competed in PEP since 2024. View our page on ASNE's website here for an overview of our past performance and videos from competition.

About This Documentation:

This library includes documentation for every year RCCF has competed. In each section's overview page, you can find links to our whitepaper and an overview of our performance that year. Additional pages provide meeting notes and detailed documentation. This is meant as a single repository of all the knowledge we have gained over the years of this project.

PEP27

PEP26

PEP26

Online Calculators

RC Boat Calculator

https://www.radiocontrolinfo.com/information/rc-calculators/rc-boat-calculator/ 

B-Series Propeller Generator

https://www.wageningen-b-series-propeller.com/ 

 

PEP26

Getting Started

What is this?

Hi, this is the documentation for PEP26 from technical notes to project budget. This page is to help orient new members about the basics of the competition, understand where the project is starting, and our goals for the project/competition.

Information about Promote Electric Propulsion (PEP) competition: https://www.navalengineers.org/pep26 

PEP26 project's main CAD tool is SolidWorks. PEP26 builds off the boat hull designed in 2025. Full SolidWorks CAD files are listed in this link: https://drive.google.com/file/d/1mpcjKZqcM0cvbklvq_0w4udm3BJp91CS/view?usp=sharing

 

Previous PEP teams

Team 2024 https://www.navalengineers.org/pep24 

PEP26

Electrical System

Parts

High Voltage System

Antenna Enclosure

Control Box

Others

Wiring Diagram

image.png

How it works

General Info

Low Voltage Initialization: The startup begins with the 4S LiPo battery, which powers the low-voltage system. The power routes through a 12V regulator and then to a 12V to 5V buck converter. This regulated 5V output powers up the Cube flight controller. The flight controller then distributes power to the RC receiver, the GPS, and the Arduino Nano used for stepper control.

High Voltage Arming: The main propulsion power relies on four 12.8 V LiFePO₄ batteries connected in series. For the high-voltage system to turn on, a sequence of safety checks must be met: the boat's safety switch must be on, the RC controller must be connected, and the arming switch on the controller must be active.

A Lua script on the ArduPilot controls sets Servo 5 output to high when the system is armed. This output is connected to a relay that completes a 12V signal circuit wired in series with the E-stop that closes a 500A rated contactor. Closing this contactor allows high voltage power to flow through a 150A fuse to the main bus bar, which then distributes power to the VESC and the 48V buck converter powering the stepper driver.

Throttle

When a throttle command is initiated by the pilot, the system relies on communication between the ArduPilot software and the VESC. The throttle input is received by the RC receiver and sent to the Cube flight controller. The flight controller outputs a PWM signal directly to the VESC. The VESC interprets this signal to dynamically control the APISQUEEN 70167 main motor, adjusting the power drawn from the 55V bus to increase or decrease thrust.

Throughout this process, the ArduPilot software streams real-time telemetry data such as battery voltage and current draw through the telemetry radio.

Steering

Steering the vessel involves translating digital control signals into precise mechanical actuation via the Arduino. A steering command from the RC controller is processed by the flight controller, which sends a PWM signal to the Arduino Nano. The Arduino Nano translates this PWM signal into the appropriate step and direction signals for the stepper driver. The stepper driver then physically rotates the 48V 5A stepper motor to move the rudder.

To maintain accurate and responsive steering, a waterproof potentiometer physically monitors the rudder's position. It feeds this positional data back into the Arduino, creating a closed control loop.

E-Stop

The emergency stop procedure is designed for physical isolation of the high-current systems while keeping the "brain" of the boat online. Pressing the E-Stop physically breaks the 12V signal loop that is wired in series with the flight controller's relay. Without the 12V signal, the 500A contactor opens. This physically severs the connection between the main LiFePO₄ batteries and the high-voltage bus bar. Power is cut to both the VESC (stopping the main motor) and the 48V regulator (stopping the rudder's stepper motor).

Because the low-voltage electronics are on a completely isolated circuit powered by the LiPo battery, the flight controller and RC receiver remain powered on. This ensures that the boat safely kills its propulsion while maintaining data logging and connection to the ground control station.

For more information, visit the GitHub.

PEP26

Part Specs

Pin Out & Specs

image.png

PEP25

PEP25

Navigation

Cube ArduPilot Installation Instructions

Telemetry Radio Manual

 

PEP25

PEP 2025 Information

Rule book Link

Major Rules

Requirements

Optional 

Deadlines

Scores

Completion Date

Possible Points

Bonus: Mid-Year Review

Feb. 10, 2025

3

White Paper

Mar. 25, 2025

20

Video Presentation

Mar. 25, 2025

20

Demo Video (200m/2 min. Operation)

Apr. 1, 2025

N/A

Race Performance

Apr. 15-17, 2025

60

Bonus (Unmanned): 60 lb payload

Apr. 15-17, 2025

5


Total Possible Points

108

PEP25

Code

Temperature sensors

CAN ports : https://discuss.ardupilot.org/t/how-to-send-data-from-arduino-to-pixhawk-using-i2c/99814


Temp sensor datasheet : https://www.analog.com/en/products/ds18b20.html 


Applets : https://github.com/ArduPilot/ardupilot/tree/master/libraries/AP_Scripting/applets 


Ardupilot forum: https://ardupilot.org/copter/docs/common-optional-hardware.html 


Temp sensor ardupilot: https://ardupilot.org/copter/docs/common-temperature-sensor.html 


Pihawks with Raspberry 

https://ardupilot.org/dev/docs/raspberry-pi-via-mavlink.html

PEP25

Hull Design

Hull Design - General Notes 
---------------------------------

Hull Composition:

The hull of our vessel has to accomplish multiple things in order to be successful. 

  1. Don't sink
  2. Go fast
  3. Fit everything nicely
  4. Don't put us in debt

The first thing it has to do is not sink, as we are designing a surface vessel, not a submarine. The way a ship doesn't sink depends entirely on its hull's ability to resist taking on water during normal use. The way we have chosen to do this with our hull is by creating a composite hull, comprised of the following layers: 

image.png

The second thing the boat hull has to do is go fast. This component is dependent on the electrical and motor teams' abilities to collaborate effectively to deliver an optimal motor for our boat. It is also, however, dependent on the hull team's ability to deliver a hydrodynamic hull. 

The hull team has chosen a catamaran design for our boat. This essentially implies that the hull will have two "pontoons" which are structurally integral to the central, primary cabin (interior, below-deck room of a ship) that houses our electronics box. The basic layout for the boat is below: 

image.png

The two "pontoons" of the boat are on either side of the electrical box, annotated by the yellow lightning bolt. They are spaced as such to prevent the boat from rolling over. The pontoons will also house the 4 batteries (blue boxes) and the payloads (red boxes). 

The third thing a hull has to do is fit everything nicely. Our hull will accomplish this by default; we will dimension it around the necessary components, which are listed below:

Component  Full dimensions Scaled dimensions Weight
Battery (x4) 12 x 9 x 7 inches 3 x 2.25 x 1.75 in undefined
Payload (x2) undefined
 undefined
 30 lbs
Electrical box (x1) 12 x 16 x 8 inches 3 x 4 x 2 in
 undefined

scale: 1/4

The fourth thing the hull has to do is prevent us from going into debt. The way we accomplish this is by using affordable materials, planning our production of the hull, and through testing scale models to avoid wasting excessive material. The production procedure, as it currently stands, is below:

Step
 Procedure
 Purpose
 Status
1 decide on a hull type

to decide on the best course of action for the mission.

 complete
2 prototype the first rudimentary iteration of the hull to allow the team members to make decisions on the hull while they are able to comprehend it as a 3d concept complete
3 prototype the next iterations of the hull in CAD  to allow each member to implement their own ideas on hull design; to allow each member to gain 3D CAD experience; to begin the process of figuring out the best general shape for the scale design in progress
4 Decide on the best CAD scale prototype for testing purposes to decide which CAD model is the most optimal; to give each member the chance to have their ideas heard and weighed --
5 Print the scale model / panel test to test the effectiveness of 3D-printed hulls; to test the printers and optimize their settings for printing panels out of PETG later on; to provide data for optimizing the thickness and infill of the panels which will be printed later on --
6 Design the skeleton of the real boat in CAD

the skeleton is necessary for the structural integrity of the boat, and for anchoring the panels along bulkheads. 

 --
7 Design the real hull in CAD  this step is necessary for simulations (OPTIONAL); the general shape of the hull will be required before we can break it up into individual panels.  --
8 Break up the CAD design into panels Each panel gets printed individually. We also need to figure out how they will be attached to the skeleton. --
9 Print the panels and 3D geometry This is necessary for assembly of the final boat. --
10 Assembly The final boat needs to be assembled. --
11 Finishing The assembly needs to be finished (plastic welds around electrical box, apply coatings, etc...) --
12 Dry testing

The Dry test is necessary for making sure the electronics won't explode. During dry testing, a single panel should be submerged in water for a few hours to determine the effectiveness of the finishing process on waterproofing the hull panels.

 --
13 Wet testing The Wet test is necessary for determining the performance of the boat in actual water. Leaks should be addressed in this phase, and they should be thoroughly patched. This phase is also necessary for determining if the hydrofoils are go/no-go, and if they need to be adjusted. --
14 Competition :D  --

-------------------------------------------------

Current hull iterations:

Author Iteration
 Image Description
Cai, Dylan, et. al 0

(cardboard model)
  • general catamaran shape
  • included hydrofoil geometry
  • 1/4 scale
Cai 1

image.png
  • pontoons were generated via subtractive manufacturing techniques (he cut the pontoons out of solid rectangular prisms with the extrude-cut tool)
  • Includes an "air-ram" geometry in the front/center which theoretically increases the lift force, aiding the hydrofoils
  • accurate dimensions
Li 1
  • (add your description here, Li)
Dylan 0
  • (add your description here, dingus)
Brooke 0
  • (add your description here, Brooke)
Anyone Else














----------------------------------------------------------------------------------------------------------------------------------------------------

Materials used for final hull:

Material
 Quantity
 Purpose
 Cost $$
PETG Plastic filament undefined All models will be made of PETG. The final boat will use PETG panels for its skin.  undefined
Waterproof Material --> Edits required

Translucent Resin (brand? type?) undefined
 Final layer of boat will be translucent resin. It will act as a sealant. undefined
Hydrofoils (type, brand, material, etc...) --> Edits required

--


--


PEP25

Notes

11/08/2024

Meeting goals

Get ArduPilot up and running on Cube

Meeting Notes

What was completed?

What is in progress?

What is the goal for the next meeting?

11/12/2024

Meeting goals

Meeting Notes

What was completed?

What is in progress?

What is the goal for the next meeting?

 

11/15/2024

Meeting goals

Meeting Notes

What was completed?

What is in progress?

What is the goal for the next meeting?

 

1/14/2025

Meeting goals

Meeting Notes

What was completed?

What is in progress?

What is the goal for the next meeting?

 


Images

 

PEP25

Propeller Design Research and Specifications

Date: 9/6/24

Meeting goals

Meeting Notes

LINKS:

https://bblades.com/props-101/#:~:text=Rake%20is%20the%20amount%20of,outboard%20propellers%20is%2015%20degrees. -Propeller 101

https://fliteboard.com/products/flite-air-pro-acai?variant=43220266189000 - eFoil with diff. propellers

https://bit.ly/4e8DVso - Tentative motor

CAESES Video Tutorials › CAESES - Design software

https://web.mit.edu/2.016/www/handouts/2005Reading10.pdf - MIT paper on propellers

Manufacturing

3D-printing for prototype and later have the propeller milled

Propeller design

We were brainstorming about the use of 2 or 3 blades due to the size of the boat.  Depending on the actual power needed to lift the hydrofoil out of the water we could reduce the amount of blades used on a counter rotating prop. Since the efficiency of the counter rotating prop design is more efficient, maybe it is possible to reduce the amount of blades from 6 to 4 on the shaft.

Counter-rotating propellers

What was completed?

What is in progress?

What is the goal for the next meeting?

Images

 

PEP25

Software Report

How, what, why?

Software Goals:

Primary

Secondary:

Control Software:

We moved away from our completely custom software setup on ESP32 last year. The ESP32 was simple and great for allowing plain RC controls, however was limited for further development. We also had no way to receive data back from the boat in real time. 

Hardware Choices:

PEP25

v


**Abstract**

            Whether one is prototyping, recreating, or even creating a new unique item there is no question that 3D printing is a positively helpful tool in the process of an item going from a fantastical idea to reality. The Robotics Club of Central Florida (RCCF) has found 3D printing an essential part of bringing forth an idea to the real world; however, this process is not without its challenges. With this paper, RCCF’s Rapid 3D team presents the challenges of designing, developing, and testing a fully custom 3D printed hull designed around a central direct drive electric propulsion system. This system is based upon RCCF’s direct expertise in robotics, specifically the need to keep component interactions simple, functional, and reliable. With that in mind, the drive assembly of the boat (Rapid 3D) features an optimized propeller, selected based on diameter and pitch to maximize thrust efficiency, a submersible pod electric motor for direct drive propulsion, and a custom-geared rudder system for both enhance maneuverability and control. The power system integrates 4 LiFePO₄ and a LiPo battery, ensuring a balance of power efficiency, safety, and redundancy. \

PEP25

Propeller Design Research Part 2

Date: 09/17/24

Meeting goals

Meeting Notes

What was completed?

What is in progress?

What is the goal for the next meeting?

Images

 

PEP25

Rudder

9/20/2024

Balanced Barn door rudder which can either be attached from just the top or form a top and bottom, which is a rudder with a shaft through the middle which will spin the rudder. 

Benefits:

Cons:

PEP25

OpenProp Design Parameters

OpenProp Design Parameters

- B-series propeller design parameters: Untitled
- B-series propeller design procedure: OptimumdesignofB-seriesmarinepropellers.pdf

1. c/D (Chord Length / Diameter Ratio)
2. Cd (Drag Coefficient)
3. t0/D (Thickness at Hub / Diameter Ratio)
4. Skew
5. Xs/D (Distance from Leading Edge to Maximum Thickness / Diameter Ratio)
PEP25

Motor

9/10/2024

By looking at the possible motors that we have chosen and comparing them with power and price we have decided to go with:

APISQUEEN 70167

Also worked on calculation in the spread sheet, Current spread sheet to calculate values(PDF):

image.png

Coming up
will need to pick out a ESC before friday.

PEP25

Motor Controllers

Main motor controller (link)

We made the decision to go with the Flipsky 75350. We made this decision because of prior years experience with Flipsky controllers and they give some of the best functionality and configuration. 

Pros
Cons
Specs
PEP25

Batteries

High Power System Batteries (link)

We will continue to use out 4 100ah Lithium Iron Phosphate (LiFe) batteries that we choose last year for our competition. These batteries were very oversized for our purposes last year but will much better suited this year with our higher power requirements. Lithium iron phosphate was chosen for it's safety to density ratio. Compared to Lithium Ion(Li-Io) or Lithium Polymer(Li-Po) LiFe is less energy dense but also comes with a more safe chemistry.  

Battery Configuration

Full Boat-Page-2.png

The batteries will be configured in a 4s configuration of the battery packs we use. If you consider the internal configuration of each pack we will be using a 16s battery configuration. 

PEP25

PCB

Old Boat PCB.zip
PEP25

Notes

Notes

09/06/24

Meeting goals

Meeting Notes

List of sensors/control connections for the boat
  • temp sensors
  • actuator communication
  • imu / GPS
  • main motor
  • Controller
  • data collection
  • e-stop control

What was completed?

What is in progress?

  • motor selection
  • controller selection
  • PCB improvements
  • battery requirements (based off motor selection)
  • boat computer decision
  • Software

What is the goal for the next meeting?

Images

 

09/10/24

Meeting goals

  • Basic EasyEDA design
    • Example project

Meeting Notes

What was completed?

What is in progress?

    What is the goal for the next meeting?

    Images

     

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    PEP25

    Full System Layout

    Full System

    High Voltage System

    High Voltage Supply

    High Voltage Distribution

    Low Voltage System

    PEP24

    PEP24

    Power and Control

    Batteries

    Battery 1

    Capacity: 71,688mah + 17,457mah + 14,206mah = 103,351mah 

    Battery 2

    Capacity: 90,007mah + 12,816mah = 102,823mah

    Battery 3

    Battery 4

    PCB Iterations


    V0.1 (Breadboard)

    Pre-PCB design that often was multiple parts of the system that would eventually become one.

    Pros
    Cons
    Components
    V0.1 (Breadboard)

     

    V1

    Version one was created by Brandon Marcellus & Juan Silva early on in the start of the project after we had started some of the basic wiring of control and data collection.

    Pros
    Cons
    V1

    IMG_0986 (1).jpg

    V 1.1 (Breadboard)

    V2

    PEP24

    PEP24 Overview

    PEP24 was RCCF's first time competing. 

    Our boat was a catamaran constructed out of layered XPS foam wrapped in fiberglass.

    This year provided a strong foundation for future years. The LIthium Iron Phosphate batteries, selected for their long life span, continued to power the team through the next two years.

    2024 Whitepaper: 

      

     
    2024 Google Photos

    image.png

    image.png