Control system for the rocking calmer "SKAT-1031"

Control system for the rocking calmer "SKAT-1031"

The system is designed to control the steering devices of the ship's side rudders, maintain the specified amplitude (magnitude) and frequency (period) of the on-board pitching of a moving vessel by changing the angle of rotation of the rudder pen in the plane of the ship's midship frame.

The rocking calmer system provides operation in two modes:

-Rocking calming mode (when the ship's speed is up to 12 knots);

-Ship rocking mode (when the ship's speed is in the range from 5 to 10 knots).

On-board steerable rudders are located sideways from the outside of the vessel's hull and create a torque that counteracts the ship's side pitching or creates it, depending on the selected mode. The total number of SR is 2 pcs. (one per board).

  1. Power supply network parameters

The system is powered by the ship's power supply (three-phase 400 V electrical network). Deviations from the nominal values of the supply network are shown in the table below:


Deviation from nominal values, %

Duration of short-term deviation, s



AC voltage











The power consumption for the system's own needs it does not exceed more than 2000 Watts (at a mains voltage of 400 V).

  1. The degree of protection of the system equipment-IP44.
  2. The communication of «SCAT-1031» with external control systems is provided by the following signals:


Analogue signals

Digital signals

Digital connection


From 4 to 20 mA (resistance is not more than 200 Оm)


«dry contact»

Modbus TCP/IP


From 4 to 20 mA (the load is not more than 500 Оm)

24V «dry contact» (relay outputs no more than 0,5A)

The main parameters provided by the SKAT-1031

  1. In terms of providing functionality:
  • ship rocking mode;
  • rocking calming mode;
  • uninterrupted communication with external ship systems
  1. In terms of providing indication and EWS (emergency warning system):
  • protective shutdown devices;
  • control of the availability of power;
  • network voltage monitoring;
  • phase break control;
  • protection against short - circuit currents;
  • parameter control and protection of pump electric motors;
  • monitoring of parameters of hydraulic system sensors;
  • uninterruptible power supply CS from UPS;
  • registration of SR and CS malfunctions, recording in a non-volatile log of accidents and warnings;
  • issuance of fault alarms for SR and CS to local and remote control posts;
  • accident acknowledgment;
  • emergency stop.
  1. In terms of providing control:
  • local control (from the buttons on the front panel of the PMS and the touchscreen of the LCD);
  • remote control of the equipment (from the touch screen of the control panel and external ship's control panels);
  • emergency stop from any control station;
  • priority of control from the local control post.

SC "Skat-1031" consists of the following parts:

- local control device (hereinafter referred to as LCD);

- control and alarm panels (hereinafter – CAP);

- pump motor starter (hereinafter – PMS);

- rotation angle sensor (hereinafter referred to as the RAS);

- tilt angle indicator (hereinafter – TAI);

- the distribution box (hereinafter – DB).


The distribution box



Structural chart of the control system "SKAT-1031"

Where are indicated:

  1. Blocks:

LCD – local control device;

CAP – control and alarm panels;

RAS PS/SB - rotation angle sensor of port side/of starboard;

PMS PS/SB – pump motor starter of port side/of starboard;

RD PS/SB – rocking device of port side/of starboard;

DB PS/SB – the distribution box of port side/of starboard.

  1. Connections:

Orange dotted line – 380V power supply;

Black line – potential-free dry contacts and analog signals;

The blue line - Ethernet;

The yellow dotted line - RS-422/485.