Ship Stern Structure Integrating Propeller Shaft Support
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Solution Overview
Problem
Existing ship designs with twin propellers face challenges in maintaining propulsion efficiency due to strength issues in the supporting structure of propeller shafts, which can lead to increased appendage resistance and decreased performance.
Innovation Solution
A stern structure design that integrates propeller shafts within the ship body, using curvature and flat portions to cover and support the propeller shafts, reducing the need for external appendages like bracket fins and bossings, thereby enhancing support strength and minimizing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If external reinforcement structures (bracket fins, bossings) are added to support propeller shafts, then the strength of the supporting structure is improved, but the appendage resistance increases and propulsion efficiency decreases
Solution Approach 1:
The patent merges the propeller shaft support function with the stern body structure by integrating reinforcement ribs directly into the stern body. This eliminates the need for separate external reinforcement structures like bracket fins and bossings, thereby maintaining structural strength while reducing appendage resistance and improving propulsion efficiency.
Solution Approach 2:
The stern body structure is designed to perform multiple functions: it provides the hull structure, supports the propeller shafts, and incorporates reinforcement ribs for structural strength. This multi-functionality eliminates the need for dedicated external reinforcement components, reducing resistance while maintaining strength.
2Loss of energy
If propeller shafts are positioned closer to the ship body center line to absorb longitudinal vortexes, then propulsion efficiency is improved, but the supporting structure strength becomes insufficient
Solution Approach 1:
The patent applies local reinforcement by adding reinforcement ribs at specific locations on the stern body where propeller shaft support is needed. This allows the propeller shafts to be positioned close to the ship body center line for efficient vortex absorption while providing localized structural strength enhancement without requiring overall structural enlargement.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A stem structure for a ship is provided with propellers, propeller shafts, and a stern structural body, Propeller shaft tubes are provided so as to correspond to the propellers and have inserted therethrough the propeller shafts which are connected to the propellers. The stem structural body extends rearward from the stern portion (3) of the ship's body, expands outward relative to the center line (C) of the ship's body, and encompasses the portions of the propeller shafts which extend rearward out of the stern portion (3) of the ship's body. The inner side of the stern structural body is located within the ship's body. The stern structural body supports, within the ship's body, the propeller shaft tubes.