Ship Heading Control

Ship Heading Control: 

Ship Heading Control Jason Chang NSWC Carderock February 2, 2000

Ship Heading Control: 

Ship Heading Control Scope of project Current issues and procedures Benefits of heading control Possible solutions Conclusions

Ship Heading Control: 

Ship Heading Control Scope of Project Investigate available technology capable of controlling the heading of ships relative to waves or currents. Limited to the T-ACS Auxiliary Crane ships

Ship Heading Control: 

Ship Heading Control Current Issues and Procedures Ship roll motion, caused by long period waves, are primary detriment to cargo handling operations in heavy weather. Current hardware and procedures allow minimal heading control. Stern anchoring system Use of main engines and existing bow thrusters Limited to very low sea states

Ship Heading Control: 

Ship Heading Control Benefits Operational experience has shown that heading control can significantly reduce roll motion, the primary cause of cargo heave and pendulation. Resulting in improved performance in heavy weather conditions. Heading control can also create lee which can be used as sheltered lighter stations. Facilitate ship-to-ship mooring process.

Ship Heading Control: 

Ship Heading Control Possible Solutions Active Rudder Conventional Stern Thruster Right Angle Drive Deck Mounted Z-Drive Retractable Azimuth Thruster Rudder Propellers Tugboats

Active Rudder: 

Active Rudder Consists of a hydraulic or electric propulsor integrated into existing rudder Utilizes existing control system Minimal impact on ship Relatively low cost

Stern Tunnel Thruster: 

Stern Tunnel Thruster Very effective system Requires extensive modification to vessel Relatively high total cost Not considered a practical options for existing vessels

Right Angle Drive: 

Right Angle Drive Consists of a swing up propeller and pod Pod can rotate and steer 360° Relatively minor modification of existing vessel compared to other systems

Deck Mounted Z-Drive: 

Deck Mounted Z-Drive Units are portable and adaptable to any hull configuration Omni-directional thrust Easy installation and maintenance High initial cost coupled with low installation cost

Retractable Azimuth Thruster: 

Retractable Azimuth Thruster Consists of hydraulic power unit, propeller and nozzle, and retraction system Omni-directional thrust Requires extensive modification to vessel

Rudder Propellers: 

Rudder Propellers Utilizes existing main engine Extensive vessel modification required High cost but effective

Tugboats: 

Tugboats No vessel modification Would require tugs to stay on station to control heading May require extra tugs in order to fulfill all JLOTS duties

Ship Heading Control: 

Ship Heading Control Conclusions Heading control can significantly reduce roll motion in moored vessels, resulting in improved performance in heavy weather conditions. Produce lee which can act as a sheltered lighter station Several options are economically justifiable as possible solutions: Active rudder Deck mounted Z-drive Tugboats

Ship Heading Control Questions: 

Ship Heading Control Questions ?