1.1 Fin stabilisers and their components
The function of a fin stabiliser, found at the bottom part of the ship’s hull, is to provide resistance to the excess rolling of ship in either direction. Many seafarers have not seen a real fin stabiliser until the ship goes to dry dock for hull inspection and surveys. This does not rule out the knowledge that every onboard engineer and officer must posses regarding the components and functioning of fin stabiliser system.
1. Two fins forming part of the hull structure of the ship, one portside and one starboard side.
These fins are connected to a fin stabiliser room on portside and starboard side of the ship from where they are operated/ controlled
Each stabiliser consists of a fin box, which houses a fin and supports the fin actuating machinery. Each stabiliser machinery unit provides the support and the means by which the fin may be rigged in or out, locked and tilted up to +/-25 degrees.
2. Two hydraulic power units located in the stabilizer room PS and SB, power the fin tilting and rigging motions
3. Bridge control panel (BCP) provides control and indicators for remote operation from bridge. The panel is installed in the BMCC.
4.Two local control units (LCU) are located in each stabilisers room. These panels are providing local indication and control of the fin.
5. Main control unit (MCU) -This panel can control fins from ECR with the same features as bridge control unit. LCU display for starboard and port is present in MCU.
6. Roll motion sensor unit (RMSU) - measures ship’s roll acceleration and provides the control signal for the roll control algorithm and interfaces to the Main Control Unit (MCU). The RMSU comprises of a solid state sensor and signal conditioning electronics. Sensor is located in MCU.
7. Fin angle feedback transmitter - provides the fin angle position signal for the servo controller. A fin angle indicator mechanically coupled to the tilt cylinder piston rod and the fin angle transmitter shows the fin tilt angle.
8. The Stroke Control Unit (SCU)- is mounted on the variable delivery pump. It provides drive and feedback of the position of the pump’s control spindle.