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Series 420 Naval Shaft Power Meter System has passed rigorous MOD and MIL testing programmes and is able to provide an accurate tool to monitor propeller shafts on ships by measuring shaft speed, torque and power.

Datum Electronics Series 420 Naval Shaft Power Meter System provides an accurate tool for naval ship performance monitoring. It is able to assess and monitor propeller shafts on naval ships by measuring shaft speed, torque and power.

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Key Features

Key Features

The Datum Naval Shaft Power Meter System was originally designed for use on the Royal Navy Hunt and Sandown Class Vessels. Later variations have been provided for the Royal Australian Navy, Korean Navy and the Indian Navy.

Datum Naval Shaft Power Measurement System

The Datum Electronics Series 420 Naval Shaft Power Meter System accurately measures the on-shaft torque (kNm), the speed of the shaft rotation (rpm) and the power (kW) that is going through the shaft. The data is transmitted from the shaft in a digital format that can be processed and scaled off-shaft. The data transmitted contains the torque level, the shaft speed and diagnostics data such as the on shaft voltage and power.

The System provides actual data on the power delivered that can be compared with the expected design performance, together with ongoing data, that will indicate any changes to this expected performance level. Condition monitoring of a system of this type is important to any modern day vessel. Being able to accurately measure and record the ship’s power and speed data can help towards determining equipment condition and efficiency. It’s a pro-active measure with the specific purpose of improving performance and efficiency through a ship transmission system.

TESTED TO DEFSTAN  & MIL Specifications

Our naval ship monitoring system assesses and monitors propeller shafts on ships, by measuring shaft speed, power and torque. Originally designed for use by the Royal Navy, later variations have been provided for the Indian Navy, Australian Navy and Korean Navy.

The ship propeller shaft power meters have been through rigorous UK MOD and USA MIL testing programmes for the harshest of environments, and are therefore verified in a number of marine conditions, including:

  • MIL Spec std. 901-D shock
  • 167-1A 2005 Vibration
  • Safety Case to JSP430
  • Shock to Def Stan 08-120
  • EMC to Def Stan 59-41
  • Selection of Marine Torsion meters Def Stan 02-606
  • Magnetic Ranging to 08-123 DS31

Other environmental tests will include Def Stan 08-123 DS28 (shock), D25 (vibration), DS24 (contamination), DS9 (temperature and humidity) and DS21 (salt atmosphere).

Single or Multiple Shaft Power Measurement Systems

The Datum Electronics Series 420 Shaft Power Meter System can either be configured for a single shaft system or for multiple (2,3 and 4) shaft systems to provide highly accurate non-contact torque measurement of shaft torque, speed and power.

Ship Performance Monitoring System Setup

The Series 420 Naval Shaft Power Meter System includes a shaft Unit which is fitted to the ship shaft to measure torsional strain and rotational speed. A separate stator unit is then fixed inline with the shaft and transmits the data off the shaft to the control unit.

Control Unit Used In Series 420 Naval Ship Performance Monitoring System | Naval Ship Shaft Power MeterA Control Unit to provide power to, and take data from, the shaft units, to calculate calibrated torque and shaft power (as a function of measured torque & speed). The Control Unit also records & displays accumulated running hours for each shaft.
Remote Display Unit Used In Series 420 Naval Ship Performance Monitoring System | Naval Ship Shaft Power MeterAn optional Remote Display Unit to display, Torque, Rotational Speed (and direction ‘AHEAD’ or ‘ASTERN’) and Calculated Power from Both Shafts.


Ship Performance Monitoring System Specifications

The Series 420 Naval Shaft Power Meter System fits ship shaft diameters between (160mm – 1100mm). The shaft installation comprises a standard stator unit that provides power to the on-shaft electronics and conditions the output signals. The stator housings are manufactured to cater for a range of shaft sizes.

  • Size 1   –           shafts 160mm – 250mm
  • Size 2   –           shafts 250mm – 350mm
  • Size 3   –           shafts 350mm – 500mm
  • Size 4   –           shafts 500mm – 650mm
  • Size 5   –           shafts 640mm – 800mm
  • Size 6   –           Shafts 800mm – 1100mm

Naval Shaft Power Meter System Installation

The Naval Shaft Power Meter System has a shaft installation supplied as a rotor sub-assembly and a stator sub-assembly. The installation onto each shaft comprises a dual bridge strain gauge installation. The installation of the rotor is followed by the installation of the stator.

The rotor sub assembly is split into two halves and bolted over the strain gauge installation. The rotor houses the rotor electronics module, acts as a carrier for the rotor coil and physical protection for the strain gauges. The shaft rotor and stator are separated by an air gap of up to +/-12mm to allow for fitting tolerances and shaft movement relative to the stator mountings.

The Control Unit is supplied as a complete assembly; it requires four physical mounting points for easy installation and connection to the shaft units, ships control systems, logging equipment and remote displays. The optional Remote Display Units are supplied as a complete assembly, with four physical mounting points.

Commercial Marine Shaft Power Meter System

We also have a commercial ship shaft power meter system, developed to meet the requirements of marine industry customers by providing continuous power output measurements, as well as aiding fuel economy and equipment maintenance planning. Robust, permanent, modular and simple to install, the commercial marine shaft power meter accurately monitors the efficiency and performance of the ship’s transmission systems, leading to large savings on running costs.

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JOSCAR registered full colour PNG


  • Measures Shaft Torque (kNm) Shaft Speed (rpm) Shaft Power (kW)
  • Installed directly on ship shaft
  • Non-Contact Transmission System
  • Simple Robust Design
  • Designed to fit variable size ship shafts
  • Single or Dual Shaft Applications





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