McGill University

Department of Mechanical Engineering

Conceptual Design

MECH 292

Final Design Report

Group number: 11

Muzammil Fazal 260610299

Catherine Pronovost 260684974

Hansol Ji 260684757

Stasik Nemirovsky 260660024

December 2nd, 2016

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Table of content

Introduction ......................................................................................................................... 3

Implemented design ............................................................................................................ 4

Modifications to the implemented design ....................................................................... 6

Bill of materials............................................................................................................... 7

Performance ........................................................................................................................ 8

Lessons .............................................................................................................................. 10

Conclusion ........................................................................................................................ 11

Acknowledgements ........................................................................................................... 12

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Introduction

Rowing is a highly popular sport in all parts of the world and in addition to

providing a source of entertainment and fun, it is efficient in building upper body strength.

A rower basically sits backward in the rowboat/canoe with the oars/paddles in the water

and pull them towards himself to propel the boat forward. After the pulling motion has

been performed the rower exerts force on the oars to pull them out of the water whilst

simultaneously pushing his or her body forward to recover the starting position. This is

considered to be one cycle or row.

Although it is a highly beneficial sport, there are some safety factors associated

with the seating position. By facing backwards, a rower has little to no idea if there are any

obstacles ahead of him/her and in order to get a better view of the course they have to turn

their head to look forward. This has been known to cause significant pain in the neck and

lower back but is a part of the sport that everybody just has to deal with. Our design concept

focused on providing the same experience that rowers enjoy from this sport, without having

to face backwards and thus eliminating any safety risks or side-effects.

It is possible to row facing forward but the motion of rowing would have to be

reversed to propel the boat in the same forward direction. We wanted to maintain the same

rowing motion as the conventional method so that rowers would not require considerable

time to adjust to the new system and be able to fully enjoy the experience without having

to constantly look over their shoulder. In addition to providing this new experience whilst

maintaining the conventional principles, our group looked to incorporate a rower’s lower

body strength in each stroke as well. This would not only generate additional power with

each stroke, but also provide a full body workout for the user.

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As a result, our design concept had two main objectives i.e. firstly, designing a

mechanism that simulates the motion of conventional rowing while allowing the user to

face forward and secondly, to install a system that incorporates the rower’s lower body

strength in each stroke to provide additional power in each stroke.

Implemented design

Following our original objectives, we came up with a concept by combining a few

of our individual ideas to achieve our goals while putting much focus on the user

friendliness aspect.

The chosen concept incorporates the use of gears to inverse the motion of the oars

and the implementation of a sliding seat to enable the use of user’s lower body power when

rowing. There are two gear mechanisms that are fitted to both sides of the canoe via the

use of vices. The oars are connected to the gear pivot using bolts and Teflon layer to reduce

friction and energy loss. The user controls the motion of the oars through the use of handles

that extend inside, towards the user from each side.

Fig 1: Top view of gear mechanism

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To incorporate the use of the lower body and for additional rowing power, a sliding

seat frame is installed at the base of the canoe. Originally we wanted to have an aluminum

frame but due to the cost constraint we decided to go with a wooden frame. An additional

metal plate is fixed in front of the frame, upon which the user pushes his/her feet and applies

a force to launch himself backwards with every stroke. This results in a translation of the

sliding seat and thereby accommodates the additional force (Lower body) that assists in the

rowing process. A spring is attached to the front end of the seat and to the feet base on the

other on the other end in order to assist in retracting the seat back to its original position

after the completion of each stroke.

Fig 2: view of the gear mechanism fixed to the side of rowboat

The entire mechanism i.e. the gears and oars are foldable allowing for easy

transportation and fit in every sedan’s trunk. The seat frame is kept as lightweight as

possible and can stay in the canoe also when not in use. In addition, we use suction cups to

improve the grip of the frame to the canoe’s bottom floor. We found it to be a very user-

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friendly feature that increases stability as well as reduces installation time. In addition, it

allows for maximum flexibility in terms of positioning and can be easily fitted for different

personal preferences.

Finally, our team was able to decide upon the chosen design concept by weighing

all the pros and cons of every individual concept and selecting the best aspects from each

concept to reach the ideal solution.

Fig 3: Top and side view of complete system

Modifications to the implemented design

For the oars part, there were many details to modify in order to obtain the best

possible design. Fist of all, we had to cut a piece of the support so that it would not be

blocked by a nut, and also we had to cut the oars around the joint with the oar mechanism

at an angle to be able to fold them completely in half.

After our first tests, the most significant change we had to implement was the

change of gear. At the firsts tests, the teeth of the four gears bent due to a load too heavy,

and therefore we produced a second gear prototype. Our second prototype was much

thicker by a factor of 2.15, and had less but stronger teeth.

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Due to the thickening of the gears, the oars had to be cut thinner, which made the

oars weaker. Thus, strong tape was wrapped around the oars to cover and reinforce the

thinner oars. When tested, the result was successful.

The suction cups were not needed to install the sliding seat in the canoe because the

weight of the rower pushed down on the sliding seat and the wheels between seat and the

base reduced the friction thus the whole system did not budge. It was determined that using

air suction cup would have produced no different result.

For the sliding seat, we had to reduce the amount of wheels from 8 to 5, because

only 5 wheels were available at Canadian Tire. We also decided that the spring feature was

both unnecessary and costly. Feet holders could have been nice, but due to the time

constraint, we had to set this optional feature aside and focus on making the others features

work properly.

Bill of materials

Item Quantity Provenance Cost

Oars 2 Kijiji 30

Gears 4 Machineries Pronovost 0

Top plate 2 Machineries Pronovost 0

Bottom plate 2 Machineries Pronovost 0

Clamps 4 Canadian Tire 22

2x4 Wood beam 1 Stasik 0

1x1 Wood plate 1 Home Depot 4

Wheels 5 Canadian Tire 12,5

Steel folded plate 1 McGill's Workshop 0

Hardware - Catherine 0

Total spent 68,5

As seen in the table above, we had the chance to receive most of our custom parts

for free. We received a sponsorship from Les Machineries Pronovost Inc. to cover the laser

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cut parts. Stasik furnished the wood for the frame of the sliding seat. The folded steel plate

we used was recycled from the Mechanical Engineering workshop at McGill. Our total

spent is 68.50$, which is 31.50$ under our budget.

Performance

The final design was tested two times throughout the design project. On the first

day of testing, many problems were detected. First of all, the sliding seat was working as

it should, except that the momentum caused by a rower sliding his seat to the front of the

canoe caused the canoe to move backward. However, the canoe movement caused by

rowing was much larger than the small momentum of the sliding seat and thus it didn’t

have a great effect on overall rowing. The momentum causing the canoe to move in wrong

direction was not visible and could not be felt by the rower. Another problem was detected

on the first day of testing; the gear teeth couldn’t withstand the force of rower pulling the

oar handles and the force of the water resisting the movement of the oar. The gear tooth

got bent and it was no more usable. The gear was too weak to be used for our design

purposes. The design objectives were not met in the first day of testing due to failure in the

gears.

On the second day of testing, the new gear was able to withstand the force and did

the tooth did not bend. Sliding seat was working as expected, it helped a rower pull the

oars with more force. Again the momentum caused by sliding seat had almost no effect

due to the larger force of oars pushing the canoe. The overall design objective of front

rowing with efficiency was met but there could be more improvements in the design.

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The final design of front rowing system has performed as expected, but there are

some improvements that could be made with more time provided. The oar handles were

colliding with the legs and sometimes with the clamps when rowing. The clamps were used

to install the upper body rowing system and it was interfering with the linear oar movement.

Also, the rower’s leg was colliding with the oar handles when user pushes down on the

handles in order to lift the oar pedals out of the water. The collisions caused some trouble

in smooth rowing. Rower had to stop and move legs or play around with the oar handles to

do another full stroke. With the clamp and the user’s leg interfering with smooth rowing,

the design can be improved to perform better. Instead of shortening the oar handles for the

oars to not collide with the leg and reduce the torque created by the rower, the gear holders

could be manufactured such that it will hold the gears and the oars at higher place than it

is right now. By making the gear holders hold the system at higher place, it will neither hit

the clamps nor legs of the user. The strokes would be more fluent without any interference

and then the whole system would be more user friendly. We could also replace the clamps

by spring clips, which are much more compact. In addition to this, a point of concern was

the difficulty in simultaneously using the rowing mechanism and the sliding seat,

particularly for new users. This transition can be made easier by incorporating a base

framework for the seat which would prevent any unwanted motion in the lateral directions.

Furthermore, straps can be used to fix the rower’s feet onto the framework which would

enable a more fluid lower body movement and hence transmit greater power into each

stroke. A lubricant could also be used for the gears to minimize friction between the teeth

and thus provide a smoother stroke.

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Lessons learned

This competition was valuable in our training as engineers as it simulated how we

might apply our theoretical knowledge in a professional environment. In addition to

familiarizing us with the various tools used in the conceptual design, this course

highlighted the importance of teamwork and communication in achieving an objective.

We gained an understanding of objectives tree, function-means tables, Pugh

matrices and House of Quality designs amongst other tools and how these resources are

implemented in the conceptual phase of a project. If we had not taken advantage of these

tools, our project would have taken considerably longer as we would have been devoid of

a streamlined process to evaluate our designs and thus finalize our concept. In addition, we

realized the importance of paying attention to detail so that we have eliminated as many

possible causes of failure. This was depicted by the failure of the first prototype due to

excessive loads on the gears. If we had run preliminary calculations on the gear diameter

and tooth thickness, such an error may have been eliminated and thereby saved us

considerable time and money.

Furthermore, we realized that teamwork and consistent communication are critical

components in accomplishing our desired goals. Seeing each team member in the group

pull their own weight throughout the semester, inspired all of us to give that extra effort at

every step of the project so to ensure that we exceed expectations. By maintaining effective

communication using Facebook groups and messages we were able to set up meetings with

relative ease and make changes if necessary to ensure that our progress was not hindered.

In addition, by actively brainstorming and providing constructive criticism to each other’s

design concepts we were able to eliminate any unwanted functions and put forth the best

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possible whilst adhering to the budget and time constraints. As a result of this competition

we were able to gain an understanding of how we should conduct ourselves in professional

environment as we would encounter similar problems and challenges while working on

group projects or tasks in later life.

In short, we are grateful for this competition as it not only provided critical technical

knowledge such as the use of Pugh matrices and objectives tree, but also impressed upon

the importance of teamwork and communication in the successful execution of a project.

Conclusion

The past three months were some of the most exciting in our educational journeys

and no, not because we learned that a person like Donald trump can become the president

of a powerful nation, but because we were able as a team to create a completely new

product from scratch.

Along the way we learned that design process is more than an intuitive thinking

that can lead you towards creating awesome things but rather an art that can be perfected

by using well structured methods. Tools like function trees, houses of quality, Gantt charts

and more revealed to us a whole new way of assessing our ideas, organizing them and

refining them into the ultimate solution given the circumstances and constrains.

As a group, we were able to get along from the very beginning and establish great

communication which now seems to be a key aspect in the success of our design project.

Dividing the work in a fair and smart manner that could benefit from the individual

strengths was also very important. We were actually able to come up with an idea that

seemed fairly complex if judging by the fellow student’s comments, and actually bring it

to life. This is definitely the cherry on top of this course and the tools we received, that

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feeling of achievement that most definitely will install confidence among our team

members when facing their next design challenge.

Overall, our design process experience was very fulfilling both on the learning and

social aspects. Working as a team is also a very important skill to have as future engineers.

Acknowledgements

We would like to thank our professor, Michael Kokkolaras who was very

supportive of our unusual idea from the very beginning and both of our TA’s Nina

Omerovic Beccalli and Ahmed Bayoumy for guiding us throughout the process.

We also would like to thank John Boisvert, technician at the Mechanical

Engineering Workshop for teaching us about sheet metal alterations, and also for the cat

stories.

Finally, our team would like to thank the team at Les Machineries Pronovost Inc.

for their time, help, sponsorship, and advices on the design and manufacturing process of

our gear mechanism. Especially, we would like to thank Mr. Réjean Pronovost, Mr. Simon

Pronovost and Mr. Christian Champagne for making this learning experience gratifying,

and by allowing us to remake some parts on a tight schedule, and for being always available

to answer our questions.