1. Final Report for Remotely Operated Vehicle, Jenny
Submitted December 10, 2014
Neptune Inc.
2609 Draper Dr.
Ann Arbor, MI 48109
Sanjana Belani
Caleb Irvin
Ryden Lewis
Emily Thayer
Ryan Wilkie
Product Engineers
Submitted in response to NASA BAA NNHI4ZDA001N for the development of ROV for
Ross Ice Shelf expedition

2. 1
Table of Contents
Executive Summary………………………………………………………………….2
Introduction…………………………………………………………………………..3
Design Overview……………………………………………………………….…….3
Model Description……………………………………………………………………5
Model Performance…………………………………………………………………..9
Full-Scale Performance……………………………………………………………..10
Conclusions and Recommendations……………………………………………...…12
References…………………………………………………………….......................13
Appendix…………………………………………………………….........................14

3. 2
Executive Summary
NASA issued a BAA requesting a Remotely Operated Vehicle (ROV) design to be deployed
under the Ross Ice Shelf in Antarctica. We are tasked with creating a prototype ROV that is able
to operate in an arctic subsea environment, and perform one of the two tasks requested by
NASA. Our ROV has been designed for the valve turning task.
NASA requires that the ROV has a mass of less than 15 kg and does not exceed the dimensions
of the transportation container (58 cm × 40 cm × 30 cm). The ROV must also be quick and
highly maneuverable in all 6 degrees of motion (forward, backward, up, down, left, right). The
thrusters, payload, and camera must be protected against collisions. The ROV must achieve a
minimum velocity of .5 m/s. Only materials provided or pre-approved by NASA may be used in
the construction of the ROV.
To complete the valve turning task, our team created a prototype ROV, Jenny. Our ROV uses a
rectangular prism shaped frame, which allows for easy attachment and adjustment of
components. The dimensions of our ROV are 49 cm × 31 cm × 29 cm, which fit within NASA’s
requirements. There is an inner frame to secure the payload, and an outer frame to attach the
thrusters, camera, buoyant material, and ballast. The open space between components allows us
to easily slide the payload into the frame since the payload is to be attached on location. We
designed the ROV to have a wide face, in order to increase our chances of hitting the valve.
However, we limited the surface area of the ROV face by minimizing the height in order to
minimize drag. All 4 thrusters are placed on the rear of the ROV to provide a high forward
speed. In an attempt to maximize the stability, we placed the payload (bulk of the mass) toward
the bottom of the ROV, and the buoyant material towards the top of the ROV.
The ROV is completed. A complete project schedule can be seen in Appendix A. We tested the
ROV at Canham Natatorium and were able to complete the valve turning task in a time of 5
minutes and 58 seconds. While testing at the Marine Hydrodynamics Laboratory (MHL), our
ROV Jenny achieved a top speed of 0.559 m/s.
A scaling factor of 2.5 will be used when scaling up the ROV prototype to full scale. Different
materials need to be used in the full scale model, due to the extreme temperature and pressure
differences in the actual environment NASA will be using the ROV in. We have decided to use a
frame made of high-strength steel and propellers made of stainless steel due to their high strength
and anti-corroding properties. Because of its high strength and low density, we have decided to
use syntactic foam for buoyancy. Lithium-ion battery would be used as a power source for the
full-scale ROV since it has a high energy density, a good weight to energy ratio, high energy
efficiency and a relatively long life-cycle.
The following report presents our ROV design, summarizes our design rationale, discusses our
model performance, and describes the scaling process and suggestions for the full scale ROV.

4. 3
Introduction
NASA has issued a BAA asking for designs of a Remote Operated Vehicle (ROV) to deploy
under the Ross Ice Shelf in Antarctica. This ROV will investigate the sub-ice sea and determine
how it has changed since the original expedition in 1977. The ROV must not exceed a total mass
of 15.0 kg or the approximate dimensions 58 cm × 40 cm × 30 cm. It must be able to go
forward, backward, up, down, left and right. It should have a rigid, cemented body structure that
is easily flood-able with a quick attachment point for the camera. The payload must be
detachable and should be strategically positioned to provide a clear line-of-sight for the video
camera. The attachment point for the tether should be on the bottom so that the tether can hang
straight down. Up to four thrusters may be used and each thruster must be wholly located inside
the structural frame and protected from bumps and collisions. The ROV must achieve a
minimum average velocity of 0.5 m/s. The ROV must be designed to either turn a valve or
collect a ring. Only approved building materials must be used; additional materials may be
approved by NASA on request.
The deep, turbulent waters of the Antarctic present several limitations to the design of the ROV.
The temperature of the waters in the Antarctic is approximately -2.16˚C (Patton, 1999). Because
of the increased depth, the pressure acting on the ROV will be much greater. Also, the density of
the salt water in the Antarctic will be higher compared to the density of the freshwater of the
testing facility. This will lead to greater buoyancy acting on the ROV. These extreme
environmental changes must be accounted for in the full-scale design of the ROV.
Design Overview
Our ROV, Jenny, uses a rectangular prism shaped frame, which allows for easy attachment and
adjustment of components. We decided that making our ROV neutrally buoyant would be the
best approach to the valve turning task, as well as the maximum speed test. In an attempt to
maximize the stability, we placed the payload toward the bottom of the ROV, and the buoyant
material towards the top of the ROV. Seen below in Figure 1 is our ROV, Jenny.
Figure 1. Rear Perspective View of our ROV

5. 4
Frame The frame of our ROV is in the form of a rectangular prism. It is 49 cm long, 31 cm wide
and 29 cm high. There is an inner frame to secure the payload, and an outer frame to attach the
thrusters, camera and buoyant material. The frame was designed with a wide face so that the
valve can be hit easily, but with a minimal height to reduce drag.
Payload The payload is inserted in the back of the vessel and it rests on two supporting pipes
running along the bottom of the ROV.
Thrusters The four thrusters are located in each of the back side’s four corners. The thrusters in
the four corners are controlled individually, and allow the ROV to be easily turned and pitched.
Buoyancy For buoyancy, we added two buoys to each side of the top and one buoy in the center
of the top. We also placed two empty 20 fl oz. Gatorade bottles below the buoys on each side.
This allows the center of buoyancy to be above the center of gravity, resulting in a stable vessel.
Camera The camera is located in the front corner of the frame of the ROV, to provide a good
viewing angle, as well as protect it from collisions. The camera is secured to the frame of the
ROV with the help of zip-ties in such a way that there is minimal movement. This helps in
maximizing the quality of our video feedback.
Control System The control system uses two switches and four buttons. The two switches
control the bottom thrusters, forwards and backward. Each top thruster has two buttons, one for
forward and one for backward. The switches are placed on the top of the controller, and the
buttons are on the front of the controller so that they are easy to reach. This makes the ROV
highly controllable because each motor can be turned on in either direction, so the ROV may be
turned in any direction using any combination of motors.
The components and their placement on our ROV can be seen in Figure 2 and Figure 3.
Figure 2. Perspective CAD Model View (Rear) of ROV
Buoys
Camera
Thruster
Gatorade Bottle
Payload

6. 5
Model Description
Dimensions and Properties The ROV frame measures 49 cm × 31 cm × 29 cm. The frame is
constructed entirely of PVC pipe, and cemented together. Five buoys are connected to the top of
the frame with zip-ties. Two Gatorade bottles are attached beneath them, one on each side, by
zip-ties. Thrusters are attached at each of the back corners. The payload canister slides into the
frame, where it is supported by two PVC pipes running down the center of the frame. The
payload and the camera are both zip-tied to the frame for easy installation. Our CAD models
seen in Figure 4 and Figure 5 display the dimensions.
Figure 4. Rear CAD Model View of ROV Figure 5. Top CAD Model View of ROV
Figure 3. Perspective View (front) of ROV

7. 6
Mass Budget
Below in Figure 6 is a table of our detailed mass budget. Most of the mass of our ROV comes
from the payload and tether.
Item Quantity Mass(g) Total(g)
Payload/Tether 1 < 10000.0 < 10000.0
PVC Pipe 400 cm 976.4 976.4
Thrusters 4 236.2 944.7
PVC T’s 16 28.5 456.0
Buoys 5 46.5 232.6
PVC 4 Ways 6 37.2 223.2
Camera 1 212.5 212.5
Zip Ties 33 1.8 58.7
PVC Corners 2 29.2 58.4
Gatorade Bottles 2 28.5 57.0
Total Mass 13291.5
Center of Gravity
The center of gravity was found by finding the moment of each mass in relation to each
dimension and dividing the sum of the moments by the total mass. The center of mass relative to
our ROV can be seen in Figure 7 and Figure 8.
XCG = ((236.175 × 49) × 4+10000 × 16.3)/(944.7+10000)
XCG = 19.122
YCG = (212.5 × 7.75)+2(236.175 × 15.5)/(944.7+212.5+10000)
YCG = 0.804
(31/2) + YCG = 16.304
ZCG = (212.5 × 29)+(236.175 × 29 × 2)/(212.5+944.7+10000)
ZCG = 1.78
Figure 6. Detailed Mass Budget of Our ROV

8. 7
Circuit Design
When designing our control box, we had to create a circuit to power the four thrusters. We
decided to power each thruster individually, and to use two single pole double throw switches
and four buttons. The bottom two thrusters are each wired to a single pole double throw switch,
meaning the operator presses forward on the switch to engage the thruster forward and
backwards for reverse. A colored wire and its corresponding black wire are attached to each one
of these switches. The switches are operated with the user’s thumbs. The top two thrusters are
controlled with buttons. We opted to use buttons rather than switches because they were easier
for the operator to press with his/her index finger (an image of the control box is seen in Figure
10). Because the buttons are single pole single throw, each of the two top thrusters required two
buttons each: one for forward and one for reverse. For each set of buttons, the thrusters’ colored
wire was attached to the forward button and the corresponding wire was attached to the reverse
button. Finally, the last remaining black wire was attached to each switch and button in series. A
circuit diagram is seen below in Figure 9 with thrusters A-D labeled on their switches/buttons.
Figure 7. Center of Mass From Front View
Figure 8. Center of Mass from Top View
Figure 10. Control Box of our ROV
Figure 9. Circuit Diagram Showing the Wiring
Configuration of our Controller

9. 8
ROV Calculations
Weight
The mass of the ROV (not including the tether), 𝑚, is 13291.5 grams. The gravity acceleration
constant, 𝑔, is known to be 9.81 m/s2
. To calculate the weight of the ROV, we multiplied the
mass of the ROV by the gravity constant, to get a weight of 130.38 N.
Buoyant Force
Our ROV is neutrally buoyant so we know that the force of buoyancy is equal to the weight of
the ROV. We know this through the equation of the sum of the forces.
Top Speed and Drag
The drag (D) acting on the ROV is given by the equation:
D = T =
1
2
CD AROV V2
(11)
where T is thrust, is the density of freshwater, CD is the coefficient of drag, AROV is the cross
sectional area of the ROV, and V is the top speed of the ROV. Using equation (13), the value of
forward T was found to be 25.22 N and backward T was calculated to be 8.19 N. The value of CD
is taken to be 1.28, AROV is 0.0899 m2
, and is assumed to be 998 kg/m3
. Using these values,
the value of forward top-speed was calculated to be 0.663 m/s and reverse top-speed was found

10. 9
to be 0.377 m/s.
Max Power
The maximum required power is given by the equation:
Prequired =
𝑉 × 𝑇
𝜂𝑜𝑣𝑒𝑟𝑎𝑙𝑙
(12)
where V is the top speed of the ROV, T is the thrust and ηoverall is the overall efficiency of the
thrusters. The value of V was calculated to be 0.663 m/s, forward T is 25.22 N and backward T is
8.19 N and ηoverall is assumed to be approximately 0.25. The value of forward Prequired was
calculated to be 66.88 W and reverse Prequired was found to be 12.35 W.
Thrust
We tested the thrust of the 4 thrusters in the GFL tank, and calculated the total thrust to be 25.22
N. To calculate thrust, we attached each individual thruster to a lever arm, attached a wire from
the lever arm to a load cell, and recorded the voltage output from the load cell. This voltage was
then converted to force (Newtons). The calculated thrust resulted in an calculated top speed of
0.663 m/s. Through rudimentary testing at tank in GFL, we were able to record a average
velocity of 0.595 m/s. The length and width of the test tank severely limited the accuracy of the
data we collected, and we were therefore unable to do testing involving the maneuverability of
the ROV. The thrust equation used is shown below.
T =
−6.8493+.019(𝑚𝑉)
2.5
(13)
Model Performance
Seen below in Figure 11 is a graph of our speed testing trials at the MHL. Our best trial recorded
a speed of 0.559 m/s, meeting NASA’s requirement of at least 0.5 m/s. A table of our trial data
can be seen in Appendix B.We had an average speed of 0.469 m/s and a standard deviation of
0.07. Our predicted speed of our ROV was 0.663 m/s. Possible reasons for not reaching our
predicted speed can be attributed to our estimated coefficient of drag being lower than actual,
and the fact that our battery wasn’t fully charged when we started speed testing. There are
several reasons why 3 of the top 4 speeds do not meet the required 0.5 m/s. During 2 of our
trials, the ROV struck either the bottom or side of the pool. In the third trial, our ROV ran into
the test valve that was placed in the MHL. While we were unable to verify the consistency of our
ROV’s speed, we were able to confirm that when tested without hitting obstructions, our ROV
met the required speed.
Figure 11. MHL Testing Velocity Graph

11. 10
We did our initial testing at the Marine Hydrodynamics Laboratory (MHL), seen in Figure
12. The water there was about 15.6 ˚C with a density of around 1000 kilograms per cubic
meter. The final competition was held at the University of Michigan Natatorium, seen in Figure
13. The water there was warmer than that of the MHL and contained chlorine. The addition of
chlorine causes the water in this facility to be more dense than previous testing locations.
During competition, our fastest and only completed trial of the valve turning task was 5 minutes,
58 seconds. We were disqualified on our first two trials due to hitting the bottom and breaching
the surface. There are several factors that lead to these disqualifications. For the first trial, we
were unable to keep the ROV off the bottom was because our Gatorade bottles used for
buoyancy were compressed from the high water pressure in the deep pool. Another issue was to
pitch our ROV, we had to be moving forward; our design did not allow the ROV to be pitched
vertically while it remained horizontally stationary. In the second test the ROV breached due to
the buoyancy being positive because ballast was removed after hitting the bottom.
Full-Scale Performance
We have designed the ROV model to be scaled-up for use in the Ross Ice Shelf, where it will be
collecting data. The full-scale dimensions of our ROV are 1.23 m x 0.78 m x 0.73 m. The ROV
will be operating in seawater where the temperature is estimated to be around - 2.16°C. It should
be capable of running continuously for 3 days. It should also be able to withstand the strong
currents, high salinity content, high corrosive properties and high pressure conditions present at
the depths of the ocean. Due to the harsh Antarctic environment, we will need to take into
account the materials we will use for the full-scale ROV.
For the material of the frame of the full-scale ROV, we have decided to use high-strength steel.
The major advantages of high-strength steel are that it has a good resistance to corrosion, is
Figure 12. MHL Testing Facility
Figure 13. Canham Natatorium

12. 11
relatively cheap and the fact that it is commonly used, so there is much knowledge of it
(Tavakkolizadeh, 2002). It also has large yield strength, which would allow the ROV to
withstand the large pressures it would experience if it were to travel to a depth of 1000 meters.
To provide buoyancy and counteract the weight of the ROV, we have decided to use syntactic
foam. Syntactic foam provides high strength and low density, and offers very low moisture
absorption.
For the propellers, we have decided to use stainless steel since it is not prone to corrosion. Due to
the lack of lighting underwater, we have decided to put headlights next to the payload. This will
increase visibility and allow the camera to capture clearly visible images.
We have decided to use lithium-ion battery as a power source for the full-scale ROV since it has
a high energy density of 144 Whr/kg, a good weight to energy ratio, an efficiency of 95 percent
and a relatively long life-cycle of roughly 500 cycles, enabling it to work continuously for 3
days. An additional benefit is that it is not prone to outgassing if subjected to overcharging
(Bradley et al., 2001).
When our ROV is fully scaled up, it needs to be able to accomplish the task of turning a valve
180 degrees, and capable of observing the subsea antarctic environment. A major strength of our
ROV is the ease of operation. Each thruster is activated by one switch or set of buttons, allowing
intuitive control of the ROV to move forward, backward, right, left, up, and down by activating
the thrusters in different combinations. This will allow the full scale ROV to efficiently
accomplish its required tasks.
Full-Scale Calculations
The full-scale calculations can be found by scaling up the thrust, top speed and maximum
required power of the model using Reynold’s scaling.
To find the full-scale thrust, we use the following scaling ratio:
λT=λ⍴ λν
2
(14)
where λT is the thrust-scaling ratio, λ⍴ is the density-scaling ratio and λν is the viscosity-scaling
ratio. We multiplied the model thrust with the calculated value of λT and acquired a value of
86.12 N for full-scale thrust.
To find the full-scale top-speed, we use the following scaling ratio:
λV=λν / λL (15)
where λV is the velocity-scaling ratio, λν is the viscosity-scaling ratio and λL is the length-scaling
ratio. We multiplied the model top-speed with the calculated value of λV and acquired a value of
0.483 m/s for full-scale top-speed.
To find the full-scale power, we use the following scaling ratio:
λpower=λ⍴ λν
3
/ λL (16)
where λpower is the power-scaling ratio, λ⍴ is the density-scaling ratio, λν is the viscosity-scaling

13. 12
ratio and λL is the length-scaling ratio. We multiplied the model power with the calculated value
of λpower and acquired a value of 166.3 W for full-scale power.
Conclusions and Recommendations
We were challenged by NASA to create a model ROV within the dimensions of 58 cm × 40
cm × 30 cm, that weighed less than 15 kg and had a floodable frame. It had to reach a minimum
velocity of 0.5 m/s and be able to turn a valve. To meet these requirements we designed an ROV
with dimensions of 49 cm × 31 cm × 29 cm. The total system weighs 4.47 kg without the battery
and tether. Knowing that the battery and tether together weigh less than 10 kg, our total mass is
less than 15 kg.
Our ROV is designed to be quick and maneuverable, with a large frontal area to turn the valve
plate with. We have four rear facing thrusters to maximize the speed of the ROV. Our best top
speed recorded is 0.56 m/s, with an average speed was 0.47 m/s. Each of the thrusters are wired
individually to contribute to the maneuverability of the ROV, so that each may be individually
fired forward or backward. When the thrusters are used, the vehicle has neutral buoyancy. Using
the thrusters at a thrust less than positive buoyancy allows controlled ascent and enables the
ROV to come to the surface in case of a power failure (Serrani & Conte, 1999).
During the competition we found that our ROV was hard to control, in both the vertical and side-
to-side directions. This is due to the fact that our pitch is controlled by rear facing thrusters, and
the thrusters’ water displacement is used to move forward and try to pitch at the same time. We
found out that our tether placement on the ROV was not optimal, and was affecting our ability to
control turning the ROV.
For future use, we recommend a creating a PVC housing for the camera, to further secure it in
place and give it a more centered view. We also recommend having a vertical thruster, so the
pitch of the ROV can be controlled while it is stationary. Another issue we need to address is the
tether placement. We are unsure of where a better attachment point for the tether would be, but
through more testing, it could be determined. A final recommendation we have for our ROV
design is floodable ballast. This would allow the ROV to be neutrally buoyant at all times,
despite the changing tether weight.

14. 13
References
Bradley, A.; Feezor, M.; Singh, H. & Sorrell, F. (2001). Power systems for autonomous
underwater vehicles, IEEE Journal of Oceanic Engineering, Vol. 26, No. 4, 526–538.
Patton, Edward, et al. (1999). "A New, Highly Efficient Deep Water ROV Buoyancy System."
Offshore Technology Conference.
Serrani, A. & Conte, G. (1999). Robust nonlinear motion control for AUVs, IEEE Robotics &
Autonomation Magazine, Vol. 6, 33-38.
Tavakkolizadeh, Mohammadreza, and H. Saadatmanesh. "Strengthening of steel-concrete
composite girders using carbon fiber reinforced polymers sheets." Journal of Structural
Engineering 129.1 (2002): 30-40.

15. 14
Trial Time (secs.) Velocity (m/s)
1 18.67 0.49
2 21.97 0.42
3 22.24 0.41
4 16.35 0.56
Appendix B. Speed Testing Table From MHL
Appendix A. Gantt Chart of ROV Project Schedule