ISO 20083-3:2019

INTERNATIONAL ISO
STANDARD 20083-3
First edition
2019-06
Ships and marine technology —
Determination of the shaft power of
ship propulsion systems by measuring
the shaft distorsion —
Part 3:
Elastic vibration method
Reference number
©
ISO 2019
© ISO 2019
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ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principles of the measurement . 2
5 Components of the device . 4
5.1 General . 4
5.2 Shaft ring . 4
5.3 Sensor . 4
5.4 Transmitting/receiving component . 5
5.5 Peripherals . 5
6 Calculation of the shaft power . 5
6.1 Shaft torque . 5
6.2 Shaft power . 6
7 Factors for determining the measuring accuracy . 6
7.1 General . 6
7.2 Sensor sensitivity . 6
7.3 G-modulus . 6
7.4 Zero adjustment . 7
7.4.1 Zero Point . 7
7.4.2 Procedure for the zero adjustment . 7
8 On-board documentation for the device . 7
Bibliography . 8
Foreword
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This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,
Subcommittee SC 2, Marine environment protection.
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iv © ISO 2019 – All rights reserved

Introduction
Selecting the optimum rating of a ship’s main engines is important for ship owners, because it greatly
affects the expenses of operations, maintenance and management as well as the ship’s construction cost.
Measuring the output of the ship’s main engine is important for confirming the ship efficiency, as well
as for assessing the possible deterioration of the propulsion equipment or the accumulation of fouling
on the hull over time. There are many methods of measuring an engine’s output: (1) measuring the
distortion of the shaft, (2) determining the fuel consumption, and (3) observing engine indicators such
as cylinder pressure gauges.
Among these methods, ISO 20083 addresses the shaft distortion measurement with a shaft power
meter, a method commonly used as the principal measurement of engine power output.
The purposes of shaft power measurement are:
— to provide a measurement of the ship’s main engine output;
— to provide information regarding the ship’s most efficient speed;
— to select optimum engine operational characteristics;
— to estimate maintenance and repair costs; and
— to monitor heavy propeller running.
INTERNATIONAL STANDARD ISO 20083-3:2019(E)
Ships and marine technology — Determination of the shaft
power of ship propulsion systems by measuring the shaft
distorsion —
Part 3:
Elastic vibration method
1 Scope
This document specifies a procedure to determine the shaft power of engine ships, by measuring the
shaft distortion using an elastic vibration type device. It gives the principles of the measurement, the
components of the device and the calculation method. It also describes the factors for determining the
measuring accuracy and specifies the on-board documentation for the device.
2 Normative references
There are no normative references in
...