Passive tank stabilisation systems

These have been proven in service for over 25 years and are designed to give an average roll reduction of between 40 and 50 per cent. Their suitability for a wide range of vessels is born out by the equipping of more than 270 ships with this technology.

Typical applications

• Ro-Ros
• Container ships
• Offshore supply and diving support vessels
• Ice-breakers
• Research and patrol craft.

Unlike passive tanks, the controlled system gives immediate reaction to any change in roll motion. They use a U-shaped system, half-filled with water, and side tanks that are connected by a water cross duct. Air cross duct(s) with integrated stabiliser valves are incorporated for air exchange between side tanks.

The controlled part of the system is the ‘active’ influence of system control together with the stabiliser valves by cyclic blocking of tank water on the upwards moving ship side to adapt the tank period the actual ship’s roll period.

Controlled tank stabilisation - benefit summary

• Delivers 40-50 per cent roll reduction
• Efficiency is independent of ship speed
• Improved ship performance and passenger comfort
• Immediate response to any change in roll motion
• Can be used in harbour to limit heeling during loading