Small-Scale Tank Testing

Once a computer aided design has been decided on, the second phase of testing will begin in Stevens’ Davidson Maritime Laboratory. Tank testing will help verify the analysis from using Orca and allow further analysis to see the hulls interaction with the water and small waves in real time. Being able to take theoretical data and compare it to real tank testing data makes it possible to see the real reaction between the hull and the water. It can highlight any imperfections, as well. Taking time to analyze the hull in tank testing will serve as an advantage and can be assurance that the hull will work as expected, whilst providing necessary information if changes need to be made.

During tank testing the resistance of the model will be analyzed for a large range of speeds according to the speed predictions for the endurance race as well as the sprint race. Because the location of the competition is at a small inland lake, calm water conditions are the most probable but the effects of small waves will also be analyzed. In addition to seeing the boat’s response in the tow tank, the optimal longitudinal center of gravity can also be found. This will be another critical part of tank testing as it will find out where weight should be positioned in order to operate at the most efficient pitch for the chosen hull design. Utilizing this aspect of design research to its fullest extent will provide an advantage in the competition as well as display how valuable and effective the Davidson Laboratory can be for hull design.

Two different chines are going to be tested on the small-scale model. The different chines are shown on the top right. Below on the right, images of the model are shown. The video below shows

a time-lapse video of the creation of the small-scale model

Computer Simulations

In order to help determine the best model to move forward with tow tank testing, Orca3D software will be used to check the stability and powering predictions. This will make sure there is a designed model that is the most efficient and effective for the rest of the powering systems. Once a confident model is built the data from the analysis software will be used to start picking out specific materials for the engine and propeller that best support the hull design. To the right, the data from the drag analysis was graphed

TECHNICAL HULL ANALYSIS

Tank Testing Results

Two chines were tested for the small-scale model: a round chine and a hard chine. To the right, images of the two different chines being tested can be seen. Full-scale tests were run from 2-35 knots, with various longitudinal centers of gravity (LCGs) used. Data for drag, trim, and heave were collected from the testing to determine which chine was better for the project. From the results, it was determined that use of the hard chine was better for the boat. Plots of the required horsepower for low and high speeds for the hard chine (as found from the testing) are shown in the lower right