Step 6: Evaluation 89
The marketing department at Johnson Outdoors recognized the growing
interest in environmentally friendly power sources for their boating industry.
Johnson Outdoors is the leading manufacturer of outdoor recreational equipment
in the world. The engineering research and development and manufacturing
facilities are located in Mankato, MN and the headquarters is located in
Racine, Wisconsin.Step 1: Recognizing the Need
for a Product or a Service
As stated above, the marketing department at Johnson Outdoors recognized the
growing interest in environmentally friendly power sources for their boating
industry. To better serve the consumers and environment, the marketing depart-
ment contacted the engineering department to discuss the feasibility of devel-
oping new generation of motors that are environmentally friendly. Increasingly,
more states were enacting regulations banning the use of gasoline boat motors in
public water ways including lakes and rivers.Step 2: Problem Definition
and Understanding
After the marketing people met with the engineers, the details of the project
requirements were defined. The design specifications included – the motor had
to move a 17 feet long Pontoon at a speed of 5 mph minimum. The motor had
to run at least for 2 hours on full battery charge. In addition, the boat operator
had to have the capability to trim and tilt (raise the motor out of the water) from
a remote console. The motor also had to be compatible with industry standard
steering wheel mechanism.Step 3: Research and Preparation
The engineers checked their existing design inventory to determine if a motor
already exists that would meet some or all requirements. Moreover, a mechani-
cal engineering student intern was commissioned to look at state regulations con-
cerning the use of gasoline vs. electric boat motors.Step 4: Conceptualization
During this phase of the design process, the engineering designers (twelve of
them) met on weekly basis to brain storm and bounce ideas off each other.
They also reviewed the information that was gathered in Step 3, and devel-
oped few concepts to pursue further. An additional idea that surfaced was the
use of an electric linear actuator in place of a hydraulic actuator. This idea
was pursued further because the potential leaks associated with hydraulic
actuators.Step 5: Synthesis
During this phase of design, the design engineers began to consider details. They
consulted pertinent codes and standards to make sure that their design was in
compliance. Most of the design work was done in ProE®and prototypes were
built in machine and electrical labs. Both technicians and engineers were involved
in the fabrication of the prototypes. An interesting result of this project was that
the unique design of the propeller required the use of a manufacturing process
known as investment casting.Step 6: Evaluation
Numerical experiments were conducted using ProMechanica®. Finite element
techniques were used to look at stresses in critical components of the motor
itself and the mounting bracket and the lifting mechanism. Numerical experi-
ments also were performed to study the hydrodynamics of propeller designs
including thrust, cavitation, speed, and drag. Using a GPS unit, the speed of the
boat was measured over a period of several hours. This test was performed to
quantify the motors’ speed as a function of time. From the collected data the
acceleration and position time functions were determined mathematically and
compared to competitors’ motors.Exploded diagram of motor.
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