Overview
MTM Ship Management Pte Ltd engaged MIT Group to carry out dry dock management and marine repair on MV Fairfield, a 15-year-old chemical tanker undergoing a 3rd special survey.
The contracted scope covered supply and installation of a water-lubricated seal assembly, forward stern tube bearing, and aft stern tube bearing. MIT engineers worked through AtZ Marine Technologies to deliver the engineering work. They also provided specialist on-site technical support throughout the project.
During the dry dock, MTM requested MIT to undertake additional work, including rudder seal overhaul and extended yard supervision. MIT completed all work within MTM’s permitted dry docking window at Cosco Chang Xing Shipyard, Shanghai. As a result, MTM subsequently commissioned MIT for two further vessel dockings.
Project Specification
Client: MTM Ship Management Pte Ltd, Singapore
Vessel: MV Fairfield, Chemical Tanker
IMO Number: 9264465
Vessel Age: 15 years (commissioned 2002)
Survey Type: 3rd Special Survey
Shipyard: Cosco Chang Xing Shipyard, Shanghai, China
Dry Dock Period: 26 September 2017 – 14 October 2017
Total Power: 9,600 PS (7,061 kW at 133 RPM)
Shaft Arrangement: Single steel shaft line with flanges and fitted bolts; one intermediate shaft and one tail shaft
Tail Shaft Detail: Bronze liners fitted at seawater-lubricated bearing positions
Propeller: Five-blade bronze fixed-pitch propeller, 5.1 m diameter, keyway and taper
Stern Tube Bearing Specification: ACM L2M composite material
Original Contracted Scope: Water-lubricated seal assembly supply and installation; forward stern tube bearing supply and installation; aft stern tube bearing supply and installation
Expanded Scope: Rudder seal overhaul; extended yard supervision and dockyard coordination; comprehensive technical reporting
Phase 1 – Scope Definition and Pre-Dock Planning
MIT carried out a pre-dock technical information exchange with MTM. They provided vessel records and shaft line history, which MIT used to confirm the work scope and produce a dry dock activity schedule. This covered responsibilities, timescales, and work procedures for all planned operations on MV Fairfield’s propulsion shaft line.
As part of pre-dock planning, MIT identified and resolved potential risk items before the vessel arrived at Cosco Chang Xing Shipyard. All seal and bearing components were confirmed to specification prior to mobilisation.
Furthermore, MIT designed, manufactured, and dispatched bespoke tooling for tail shaft removal and bearing installation ahead of engineer mobilisation.
Phase 2 – Dry Dock Mobilisation and Tail Shaft Removal
On mobilisation to Cosco Chang Xing Shipyard, MIT’s engineer coordinated with yard management and MTM’s attending technical team to confirm the dry dock programme and working sequences.
MIT carried out tail shaft removal from the single steel shaft line was carried out in accordance with the planned work procedure. The shaft line comprised one intermediate shaft and one tail shaft, connected with flanged joints and fitted bolts. The shaft line was de-coupled and the tail shaft withdrawn from the stern tube assembly.
Following removal, MIT inspected the tail shaft, including the bronze liners at the seawater-lubricated bearing positions. The inspection established the extent of refurbishment of the marine shaft required and confirmed the dimensional condition of the liner surfaces relative to the forward and aft bearing landings in the stern tube.
Phase 3 – Stern Tube Bearing Replacement
With the tail shaft withdrawn, MIT removed the forward and aft ACM L2M composite stern tube bearings from their respective bearing landings. The stern tube bore was cleaned and dimensionally inspected at both positions to confirm bore condition ahead of bearing installation.
After this, MIT installed replacement forward and aft ACM L2M composite stern tube bearings were installed to the water-lubricated stern tube arrangement. Dimensional verification at each position confirmed correct bearing installation and diametral clearance within specification.
Additionally, bearing replacement at the 3rd special survey is consistent with normal operational lifecycle for ACM L2M composite bearings at seawater-lubricated positions after 15 years of service.
Phase 4 – Stern Tube Seal Overhaul and Rudder Seal Overhaul
MIT used bespoke tooling to install the water-lubricated seal assembly to the stern tube arrangement following completion of bearing replacement and dimensional verification. As well as this, the team completed quality verification checks prior to tail shaft reinstatement.
Our engineers also carried out overhaul of the vessel’s rudder seal during the same dry-docking period. For reference to a related stern tube seal programme, see Stern Tube Seal Inspection for a Cruise Ship. This case study demonstrates our approach to seal system condition assessment and class-compliant overhaul.
Phase 5 – Expanded Scope and Yard Supervision
During the dry-docking period, MTM added rudder seal overhaul and extended yard supervision to the original contracted scope.
MIT’s dry dock supervision covered direct supervision of yard personnel across all work activities, liaison with MTM’s technical team, and supplier coordination for materials and services required during the expanded scope.
Moreover, MIT completed the additional work within the original dry docking window without extending the programme.
Phase 6 – Commissioning, Technical Reporting, and Project Close-Out
On completion of all installation work, MIT commissioned the stern tube seal assembly, forward and aft ACM L2M composite stern tube bearings, and rudder seal were commissioned to confirm correct function of the propulsion shaft line prior to undocking.
MIT delivered a comprehensive technical report to MTM covering all work completed during the dry-docking period, including findings from tail shaft removal, bearing removal and inspection, and seal installation.
The report provides a documented record of propulsion shaft line condition at the time of the 3rd special survey.
Discuss Dry Dock Management for Chemical Tankers and Product Tankers with MIT Group
MIT Group provides specialist dry dock management, propulsion shaft line inspections, stern tube bearing replacement, seal overhauls, and technical supervision for chemical tankers, product tankers, and other commercial vessels.
Contact us to discuss your vessel’s dry-docking requirements.
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