Using paperless data recorders for monitoring and controlling bilge water discharge in the marine industry

Martin Binney

August 10th, 2021 

Martin Binney,

Global Product Line Manager, Recording and Control

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Bilge water is a mixture of fresh water, sea water, oil, sludge, chemicals and other fluids that accumulates in bilge wells, the lowest compartments below the waterlines of a ship.

Accumulation of contaminated bilge water into the bilge wells is inevitable as it originates from a variety of sources – tank overflows, cleaning, maintenance, drains and leaks. If the bilge wells overflow, bilge water could rise up to or above the floor plates, become a threat to the engine room, lead to accidents, emergency situations or even disturb the stability of the ship.

To avoid these risks, the bilge water is periodically pumped out of the bilge wells using bilge pumps as shown below:

The International Convention for the Prevention of Pollution from Ships (MARPOL) states that bilge water cannot be pumped directly into the sea unless for the purposes of securing the safety of a ship or saving life at sea. Instead, it must first be treated to reduce the level of suspended oil particles to a permissible limit of 15 ppm or less and can only be discharged when the ship is at sea.

Vessels in violation of this legislation are fined heavily and in some cases crew members may even face prison sentences. 

Accumulated bilge water from the bilge wells is pumped into bilge water holding tanks by a bilge pump. The contents of the bilge holding tank are then passed through treatment equipment to reduce the oil content to below 15 ppm. If the oil content is still above 15 ppm after treatment, the bilge water is recirculated back to the holding tank.


Keeping an accurate record of discharges and the location of discharges is very important for vessels to prove that they adhere to MARPOL legislation. ABB’s Recording and Control products offer a world-class solution for management of shipboard bilge water.

ABB’s ScreenMaster RVG200 recorder offers a versatile and secure solution for data recording in marine bilge water discharge applications.

The RVG200 is ideal for recording bilge well level, holding tank level, bilge alarm status, bilge pump status, bilge discharge and GPS coordinates of discharge. The recorder provides a visual representation of the whole process (see diagram) with the convenience of fingertip control of the screen.

Furthermore, to help satisfy MARPOL requirements for logging of the location and content of discharges, the RVG200 can be connected to a GPS via serial communications using NMEA protocol. This enables the ship’s GPS co-ordinates to be logged alongside data on discharge volume and water quality.

This data is time and date-stamped, with the GPS co-ordinates added as annotations which are then entered into the RVG200’s alarm / event log. The data can be imported into ABB’s DataManagerPro historical data review software on a PC for permanent storage and subsequent review.

GPS is just one of a range of new functions added to the RVG200 to help users get more from their recorded data. Other features include:

  • High security data recording – encrypted data storage
  • Customisable process mimic, providing a visual representation of your process
  • Remote access and monitoring via Ethernet
  • Automatic data collection via Ethernet, combined with powerful data analysis using DataManager Pro software
  • Hosedown protection to IP66 and NEMA 4X

For more information about our ScreenMaster paperless data recorder range, visit our paperless recorders portal page.

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