Marine Roll & Pitch Control AS

North Sea Electronics AS has been hired by Marine Roll & Pitch Control AS to develop the control system for a down-scaled prototype.
Successful dynamic tests was carried out at Stadt Towing Tank AS.

See animation video on YouTube
MRPC Datasheet - Active Stabilization

Video and interview from Teknsik Ukeblad (Weekly Technical Magazine)

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Quote from MRPC Datasheet:

Technical description
The solution is based on open ballast tanks to sea in vertical direction, stretching over the sea water level. Utilizing negative- and positive pressure to work counter- phased towards waves. High volume air compressors, working with low pressure and vacuum manage volume in these tanks. The Active stabilization controller provides optimal filing in these tanks based on input from the ships movement.

Functional description
The center level and volume in the tanks is at the variation sea water level. This is to enable the system to “catch” the waves and work together with the nature.

“Catching” the waves enables filling the tanks with seawater without any power consumption. If more filling or load on the tanks is needed, this is applied through the suction side of the compressors.

The compressors, working at high volume of air, but with low pressure and vacuum,
require low power consumption.

Application
All ships requiring minimal ship movement for operation will benefit from a stabilization system, enabling them to expand the operational weather window.

Active Stabilization will ensure this maximum movement in worse weather than today.

The solution can be implemented in all new constructions, and in most cases in existing ships.

Model verification
Through a model test at Stadt Towing Tank, using a Ramform model vessel as a test bed for the system all simulation models is verified. The model was fitted with transparent ballast tanks, valves and sensors necessary to implement the control system. Implementation of the control system has been done by Marine Innovation. 

The tests conclude that the stabilization principle is able to reduce the roll and pitch  movement of a vessel significantly.

By controlling the filling of ballast tanks, based on feed‐back from vessel dynamics, it is possible to reduce movements of a vessel significantly. The reduction is dependent on available volume in the ballast tanks. Largest reduction is obtained with the active system by using positive and negative pressure to control ballast tank filling. The passive system has also been proved to reduce the movements of the vessel significantly.