Stability of Floating Vessels
Source: Alexander S Rattner and Kevin Rao Li Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA
The objective of this experiment is to demonstrate the phenomenon of stability of floating vessels - the ability to self-right when rolled over to the side by some external force. Careful design of hull shapes and internal mass distribution enables seagoing vessels to be stable with low drafts (submerged depth of hull), improving vessel maneuverability and reducing drag.
In this experiment, a model boat will first be modified to enable adjustment of its center of mass (representing different cargo loadings) and automated tracking of its roll angle. The boat will be placed in a container of water, and tipped to different angles with varying heights of its center of mass. Once released, the capsizing (tipping over) or oscillating motion of the boat will be tracked with a digital camera and video analysis software. Results for the maximum stable roll angle and frequency of oscillation will be compared with theoretical values. Stability calculations will be performed using geometric and structural properties of the boat determined in a computer aided design environment.
1. Measuring maximum angle of stability
- Select a small model boat. A relatively simple hull design is recommended to reduce analysis complexity in Sections 3 and 4.
- Connect a lightweight brightly-colored vertical mast to the boat (blue recommended). The provided MATLAB code tracks the position of the mast in the video by looking for bright blue pixels in the image. If a different color mast is used, the imag
| Total mass (m, kg) |
Center of mass (Hcm, m) |
Center of buoyancy (  , m) |
Moment of Inertia (Izz, kg m2) |
| 0.088 Application and Summary This experiment demonstrated the phenomena of stability of floating vessels and how ships can stay upright even with relatively high centers of mass. For example, in the representative results, a small model boat with a center of mass (Hcm = 5.3 cm) well above the water line (Hwater line ~ 1 - 2 cm) could return to its upright position after being tipped to a ~25° angle. In the experiments, the maximum stable angle was measured for a model boat with different vertical centers Tags Floating VesselsStabilityPerformance MetricsStaying UprightPositive BuoyancyCapsized VesselSafety And ComfortCrew And CargoOrientationVessel StabilityTradeoffDesign OptimizationFuel EfficiencyManeuverabilityShape And Weight DistributionExperimental TestingComputer aided Design SoftwareBuoyancyGravityObject Orientation Skip to... ABOUT JoVE Copyright © 2024 MyJoVE Corporation. All rights reserved |
