This is an example of a recent project we took on as part of our MyDriveTrain Consultancy service package. The project was to convert a traditional fishing vessel to electric propulsion. This article will showcase our approach and the expertise we provided during this complex conversion process.

Project Overview

The vessel, a Cygnus 32 fishing boat built around 1980, was powered by a Perkins M130C engine, with a single 50mm diameter stainless 316L shaft and a PRM 750D2 gearbox. The vessel owner aimed to transition to a more sustainable and efficient Bellmarine electric propulsion system.

Requirement Analysis

Our involvement began with an in-depth requirement assessment. The client needed a repowering estimate for the conversion to an electric Bellmarine system. Our task was to carry out torque measurements on the existing setup to understand the power usage and operational profile.

Torque Measurement Parameters

We recorded torque on the propeller shaft, considering the following parameters:

• Prime Mover: Perkins Sabre M130C
• Prime Mover max. Torque: 430 Nm @1500 rpm
• Reduction gear ratio: 1.995:1
• Shaft: OD 50 mm
• Material: 316L

Work Carried Out

On-site, we installed a strain gauge kit to the propeller shaft to record propulsion power usage. Over 8 hours, the vessel performed typical operations, and we collected data on power consumption during transit and pot hauling.

Results and Analysis

The data indicated that a 40 kW motor would suffice for propulsion, given efficient propeller matching and sheltered water operations. For an 8-hour workday, we calculated the total energy requirement, including propulsion, the line hauler, and auxiliary instruments and appliances, to be approximately 53 kWh.

Provisional Equipment Proposed

Based on our findings, we proposed:

• A 40 kW continuous rating motor
• A 144-volt 61.4 kWh battery pack
• Appropriate charging solutions considering the pier’s power supply

Design Considerations

Our design considered the dual station setup, the vessel’s weight, and the potential for future overnight trips requiring a generator set.

Conclusion

The conversion to electric propulsion aligns with environmental concerns and promises operational efficiency and cost savings in the long run. MyDriveTrain Consultancy’s tailored approach ensured the vessel’s specific needs were met, paving the way for a successful conversion.