Vessel Name: CS Recorder (Global Marine Systems)
Date: November 2017
Type of project: Field Service – Thruster oil stop leak service
Customer Contact: Jeremy Lloyd – Ship Superintendent
Project Engineer: Clive Wilson
Project Location: Portland Port, Weymouth, United Kingdom
Initial Enquiry
CS Recorder contacted ATZ for assistance with a suspected leaking shaft seal on the Stern Tunnel Thruster. The enquiry was for Abcon stop leak additive.
Global Marine Services had previously successfully used Abcon from ATZ, on a Sterntube tube seal leakage issue.
The Teflon particles in Abcon are chemically attracted to the high carbon content seal rings and act in the following ways;
- Abcon coats the seal ring, and this interaction slightly swells the seal ring rubber which then forms a tighter seal on the liner. The slight swelling can also close small cuts and abrasions caused by foreign debris (fishing nets etc).
- The slight increase in seal ring volume, due to the swelling, causes a small reduction in specific gravity of the rubber, which offers greater seal flexibility (very useful where seal rings are age hardened, or are operating in cold water (<10C).
- The long chain Teflon particles initially pass through any damage in the seal ring. Eventually the Teflon particles mesh with each other at the point of leakage forming a long friction Teflon plug which will stop the leakage.
The Abcon will also readily mix with seawater forming a low friction, and lubricating, paste
This case study describes the attendance by ATZ to combine the additive with the oil in the sealing chamber of the Thruster.
Project Objectives
Provide Abcon and service expertise for the seal leakage issue on the Stern Thruster seal.
Reduce, and if possible eradicate, the oil leakage.
Project Description
Prior to attending, ATZ confirmed that Abcon ‘Thruster SLL’ was the correct product within the Abcon range, for this application. That is:
- Compatible with the Mobil Gear 600XP100 lubricating oil in the Thruster
- For leakage rates up to 20l/day
On attending CS Recorder, the ATZ engineer studied the Thruster oil lubricating circuit and specification with the on-board engineer to:
- Identify Thruster seal lubricating circuit
- Confirm lubricating circuit volume
- Confirm dosing volume required for 20% mix of Abcon with the Thruster oil
With the dosing plan identified and agreed, the correct volume of lubricating oil was removed from the header tank to allow dosing with the identified volume of Abcon.
This was simply carried out by pouring the Abcon into the tank.
For the Abcon product to begin the process of healing the leaking shaft seal, CS Recorder needed to operate the Thruster, which was the intended plan of the crew on leaving Portland.
Conclusion
ATZ identified the correct product and met urgent delivery requirements of Global Marine Systems
ATZ mobilised local field service at short notice to attend CS Recorder and dose the Thruster seal tank.
CS Recorder joins an enviable list of vessels that have successfully used Abcon stop leak products. Enabling continued leak free operation of the vessels until a planned dry dock to overhaul troublesome seals in stern tubes and thrusters.