Case Study
Background
The ship is a state-of-the-art 450-foot-long dry bulk barge used to transport 18,000 tons of bulk cargo from Florida to New York. The vessel was experiencing poor directional stability when fully loaded.
Objectives
The primary goal for NETSCo was to enhance the directional stability during towing operations.
Challenge
The issue with the poor directional stability when fully loaded was leading to increased towing difficulties and additional operating costs.
A review of analyses was performed by National Research Council Canada – Ocean, Coastal, and River Engineering Research Center, of the barge’s yawing behavior using Computational Fluid Dynamics (CFD) and physical model testing provided by ASR to pinpoint the most effective skeg design. They recommended modifying the recommended skeg shape for easier fabrication without compromising on performance. Performing structural design, and overseeing fabrication and installation to ensure quality and conformance to requirements.
Thus, eliminating the need for a secondary tugboat, reducing overall towing costs.
Project Scope
The process unfolded through several critical stages:
- CFD Analysis and Model Testing:
The Client sought expert analysis, from National Research Council Canada, to determine the ideal skeg configuration that would resolve the barge’s issues with directional stability.
- Design Revision and Structural Engineering:
NETSCo reviewed the analyzed data and proposed a modified skeg design that simplified fabrication while maintaining the effectiveness of the skegs. NETSCo designed the structural details and determined the required scantlings for the skegs.
- Shipyard Selection, Fabrication and Onsite Construction Representation:
NETSCo developed construction specifications, and provided assistance in identifying a suitable shipyard for the construction fabrication, and the installation of the new skegs. During the construction phase, NETSCo representatives were present to oversee the process, ensuring adherence to the design specifications and quality standards.
The implementation of NETSCo’s towing skeg design yielded immediate positive results:
- The barge’s directional stability issues were resolved; the barge followed the towing line behind the tugboat without deviating side to side.
- The modifications led to a more straightforward fabrication process, reducing time and costs.
- The successful outcome meant that a secondary tugboat was no longer necessary, resulting in substantial towing cost savings.
- The client was highly satisfied with the project, as it directly impacted the operational efficiency and cost-effectiveness of their vessel.
The structural design and modifications put forth by NETSCo, along with the fabrication and installation efforts of Detyen’s Shipyards Inc., and the hydrodynamic simulations by National Research Council Canada – Ocean, Coastal, and River Engineering Research Center, delivered an efficient and cost-saving outcome.
