Measurement of Vessel Torque and Power

Preparing and installation portable torque meter

A portable rotary torque meter, powered by a battery, was installed on the vessel’s power shaft. This shaft load was both thrust and torque. The measurement focused on the output shaft’s torque and compensated thrust load from measurement, recorded against vessel speed.

Torque vs time

The total test duration was 28 minutes. The engine speed was increased in steps from 100 RPM up to 2800 RPM. The measurement device recorded engine speed, torque, power, and vessel velocity synchronously, and in addition to displaying the data in real time inside the vessel cabin, it also saved the information in an txt file for analytical purposes.

Engine Power vs Rpm

At each engine speed, related torque was measured and power of engine was calculated.

Comparison of the measured Power with the Manufacturer’s Graph

This graph presents a comparison between the measured power-rpm graph of the vessel engine and the manufactured document. As observed, when the vessel operates at its Full RPM, the exact maximum power declared by the manufacturer was measured by the Torque meter. This indicates an equivalence between the vessel’s maximum power output and the maximum power measured during this test. The engine was able to produce the maximum allowable power declared by the manufacturer. Consequently, this method can serve as a suitable approach for estimating the vessel’s maximum power consumption in sea trials or bollard pull tests

Graph of Power vs. Vessel Speed

One of the most features of portable torque meter is the measurement of vessel speed completely synchronously with torque and power. The result of such measurements is a graph of the vessel’s engine power versus vessel speed. From this, one can derive the efficiency of the hull and propulsion system, and use this data for health and condition monitoring.