Concept Design of a Simple Marine Dry Dock (Without Gate)

Abstract

This article explores various options for facilities used in underwater ship repair, including Dry Dock, Ship Lift systems, Floating Dry Docks, and Simple Slipway systems with cradle and winch. Such facilities are crucial to any ship repair operation. Among these, Dry Docks are known for their high capital cost and limited capacity to repair only one ship at a time. This makes them less appealing unless there is substantial demand for ship repairs and the dock can accommodate larger vessels, which offer higher revenue potential. In contrast, systems like Slipways and Ship Lift provide the flexibility to repair multiple ships simultaneously. Despite the high initial cost, Dry Docks are the simplest to operate and have the longest lifespan among ship repair infrastructure. The article focuses on designing a cost-effective Dry Dock for a small shipyard on the river Ganges in Kolkata, India. To keep costs low, the proposed design eliminates the front gate and uses sheet piles for the side walls instead of traditional pile construction. This approach reduces civil construction expenses while still meeting the region’s ship repair needs. The dock’s size has been optimized based on both location and cost considerations. A budget estimation and demand projection for the facility are provided. A basic cash flow analysis demonstrates that the ship repair complex would be economically viable and meet the long-standing demand in Kolkata and nearby areas. Although detailed economic metrics such as EBITDA and PTA were not calculated, the project’s financial feasibility is supportsed by its internal rate of return (IRR).

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