Optimized fishing trawl net

Angle It Right: How a Bevel Can Boost Fishing Gear Efficiency

Lena Kashyap in Tech & Innovation December 2025 • 4 min read.

"Unlock the secrets to optimizing trawl otter-boards with the right bevel angle for enhanced hydrodynamic performance and reduced energy costs."

In the world of commercial fishing, trawl doors (or otter-boards) are essential for spreading the trawl net and maximizing the catch. These seemingly simple devices are subject to complex hydrodynamic forces, and even small improvements in their design can lead to significant gains in efficiency and reduced fuel consumption.

Researchers are constantly seeking ways to optimize otter-board design. Early studies date back to the 1980s, and ongoing research aims to meet the increasing demands of offshore fishing. One promising area of investigation is the effect of bevel angles on the hydrodynamic performance of three-layer parallel plate otter-boards.

This article dives into a detailed study that analyzes how different bevel angles impact the lift, drag, stability, and overall efficiency of these specialized otter-boards. We'll break down the key findings and explain how this knowledge can be applied to improve trawl fishing practices.

Finding the Perfect Angle: Bevel Design and Hydrodynamic Performance

The study focused on otter-board models featuring three parallel plates, each with a distinct bevel angle. Researchers tested four different bevel angles (8°, 10°, 12°, and 14°) in a wind tunnel at a consistent wind speed of 28 m/s. They then meticulously measured several key performance indicators:

These parameters were used to assess the hydrodynamic performance of each model. The ultimate goal was to identify the bevel angle that provided the best balance of lift, drag, and stability.

Drag coefficient (Cx)
Lift coefficient (Cy)
Pitch moment coefficient (Cm)
Center of pressure coefficient (Cp)
Lift-drag ratio (Cy/Cx)

The results revealed that a 12-degree bevel angle achieved the highest lift coefficient and lift-drag ratio. Specifically, the maximum lift coefficient was 2.598 at an angle of attack of 65°, and the maximum lift-drag ratio was 2.607 at an angle of attack of 37.5°. For stability, the 8-degree bevel angle demonstrated superior performance, with an absolute Cm value of 0.174 and a Cp variation coefficient of just 4.37%.

The Future of Trawl Design: Stability, Efficiency, and Refined Otter-Boards

This research demonstrates the significant impact that even small design changes, like adjusting bevel angles, can have on the performance of trawl otter-boards. The key takeaway is that a 12-degree bevel angle appears to optimize lift and lift-drag ratio, while an 8-degree angle enhances stability.

These findings provide valuable insights for optimizing otter-board design. By carefully selecting the appropriate bevel angle, fisheries can improve the efficiency of their operations, reduce energy consumption, and enhance the stability of their fishing gear.

Further research could explore other design parameters and their interactions with bevel angles to achieve even greater improvements in otter-board performance. The ongoing pursuit of efficiency and sustainability will continue to drive innovation in fishing gear technology.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1051/matecconf/201712805003, Alternate LINK

Title: Effect Of Bevel Angle Of Three-Layer Parallel Plate On Hydrodynamic Performances Of Otter-Board

Subject: General Medicine

Journal: MATEC Web of Conferences

Publisher: EDP Sciences

Authors: Lei Wang, Lu Min Wang, Yu Zhang, Ai Zhong Zhou, Yong Li Liu, Wen Wen Yu, Xun Zhang

Published: 2017-01-01

Everything You Need To Know

How do 'lift coefficient', 'drag coefficient', 'lift-drag ratio', 'pitch moment coefficient', and 'center of pressure coefficient' relate to trawl otter-board performance?

Trawl otter-boards use bevel angles to optimize performance. The 'lift coefficient' (Cy) represents the upward force generated, while the 'drag coefficient' (Cx) indicates resistance. The 'lift-drag ratio' (Cy/Cx) shows efficiency, and 'pitch moment coefficient' (Cm) relates to stability. 'Center of pressure coefficient' (Cp) affects balance, crucial for trawl net spread and reduced energy costs in fishing operations.

What specific bevel angles were tested, and what were the key findings regarding the 'lift coefficient', 'lift-drag ratio', and stability of trawl otter-boards?

The study indicates that a 12-degree bevel angle provides the best balance of lift and drag, achieving a high lift coefficient of 2.598 at a 65° angle of attack and a lift-drag ratio of 2.607 at a 37.5° angle of attack. However, an 8-degree bevel angle offers superior stability, as measured by an absolute Cm value of 0.174 and a Cp variation coefficient of 4.37%. These findings highlight the trade-offs between lift and stability in otter-board design.

In what ways does adjusting the bevel angle on trawl otter-boards affect hydrodynamic performance, and how can these adjustments lead to energy savings?

Adjusting the bevel angle on trawl otter-boards directly influences their hydrodynamic performance. A well-chosen angle can maximize the lift coefficient, reduce the drag coefficient, and enhance overall stability. Optimizing these factors can lead to significant energy savings, increased catch efficiency, and improved maneuverability during trawl fishing operations. These adjustments can substantially reduce fuel consumption and operational costs.

What aspects of otter-board design were not investigated in this study, and how might those factors also impact hydrodynamic performance?

While the study examines the impact of specific bevel angles (8°, 10°, 12°, and 14°) on three-layer parallel plate otter-boards, it does not delve into the material composition or surface textures, which also contribute to hydrodynamic performance. Further research could explore how different materials or surface treatments interact with these bevel angles to further refine trawl otter-board designs. Additionaly the study focuses only on wind tunnel tests and not on real world performance.

What are the potential implications of these findings for the future of trawl fishing practices, and how could implementing these adjustments lead to more sustainable operations?

The findings suggest that by carefully selecting bevel angles for trawl otter-boards, fishing operations can achieve notable improvements in fuel efficiency and catch rates. Implementing a 12-degree bevel angle can maximize lift and reduce drag, leading to lower energy consumption and a higher lift-drag ratio. This adjustment enhances operational profitability and minimizes the environmental impact of trawl fishing. Conversely, prioritizing an 8-degree bevel provides greater stability. Combining both results offers the potential for more sustainable and effective practices in offshore fishing.