Results and Conclusions

The final test of the SeaPerch, before one propeller broke, enabled the group to determine that the newly designed SeaPerch moved at a speed of .412 meters per second. The new design of the SeaPerch covered a distance of 12.8 meters in 31.1 seconds, whereas the original design covered this distance in 40.7 seconds. Furthermore, the original design of the SeaPerch moved at a speed of .314 meters per second. This proves that the group was in fact successful at altering the SeaPerch in order to make it more hydrodynamic. The SeaPerch was able to move more smoothly and efficiently through the water, allowing it to move at a quicker pace. The group increased the speed of the SeaPerch by 31.2%. This is calculated by taking the speed of new design, subtracting the speed of the original design, dividing that amount by the speed of the original design, and multiplying by 100 to get a percent.

.412 m/s - .314 m/s  x 100  =   .098 m/s  x 100 = 31.2%
         .314 m/s                          .314 m/s

Overall, the group was successful in completely the goal of making the SeaPerch more hydrodynamic. Unfortunately, the data is based on the assumption that the SeaPerch would have continued at the same pace across the rest of the width of the diving well. If the group had had more time to accomplish the task, more success could have been reached, and the propeller could have been repaired. The group was limited since the SeaPerch kit was not given to the group until the end of week four, which only left about five weeks of work time.

Week 9: Overview

During week nine, the group altered the SeaPerch with corrections discovered during testing. More  foam was added to correct the SeaPerch's buoyancy. The size of the surface area was decreased when the dimensions were shortened, therefore the weight was not evenly distributed causing the SeaPerch to be heavier in the back and sink during the first test. New thicker and denser foam was purchased to aid in better floatation. The position and amount of slant of the propellers were slightly modified in the hopes of straightening out the movement of the SeaPerch.

Note: In addition to making changes in the the design of the SeaPerch, the group took into consideration the factors the environmental factors that affected the collected data. During the first test of the new design it was found that there was a current in the diving well of the pool at the DAC. As a result, the group made an effort to reduce the effect of the current by eliminating unnecessary motion in the diving well.

When the perch was tested a second time with the alterations, it covered half the distance of the diving well before one of the propellers broke; this distance was covered in 15.53 seconds. After the breakage, the SeaPerch began spinning in circles, and could not complete the full length of the pool, due to excessive power on one side of the SeaPerch. Assuming the perch would have continued at the same speed, it would have crossed the entire width of the diving well in 31.1 seconds. That means that the newly designed SeaPerch was moving at a speed of .412 meters per second. This is calculated by taking the width of the diving well, which is 12.8 meters long, and dividing it by the time it took the SeaPerch to cross the length of the pool. The original design of the SeaPerch moved at a pace of .314 meters per second.

Figure 1: A video of the movement of the SeaPerch once the propellor broke

Figure 2: The propeller fell off due to a error in the glue attachment and soldering

Figure 3: A closer view of the error in the attachment of the propeller

Final Design Built

Final Design of the SeaPerch: Construction

Figure 1: The front of the SeaPerch with added plastic top

Figure 2: The back of the SeaPerch with added plastic ring to hold the swim cap

Figure 3: The top of the SeaPerch with the three horizontal propellors

Figure 4: A side view of the SeaPerch with the swim cap on, finished product

Figure 5: The front view of the finished SeaPerch design. This is where water will flow in

Figure 6: The back view of the finished SeaPerch, the funnel shape in order to allow faster movement

Week 8: Overview

During week 8, the group finished the construction of the final design of the SeaPerch. Two pieces of plastic were added to the top and the back of the SeaPerch so the swim cap could be attached. One swim cap is stretched from the back of the SeaPerch to the middle, in order to create a funnel for the water. The three propellers all face horizontally, pushing water out of the smaller hole in the back. This will allow a greater push forward, making the SeaPerch faster. The group brought the SeaPerch to the Drexel pool in order to test if the SeaPerch was in fact more hydrodynamic. There were some flaws in the design that will be repaired before testing again. The SeaPerch sank to the bottom of the pool, which means more foam must be added. This is due to the fact that there is less surface area, so the weight was not distributed evenly. Also, the SeaPerch pulls left while it is being steered, and does not ride straight. This could be due to one motor being stronger than the other, or the propellors were not attached properly.