Objectives

To engage a qualified service provider capable of delivering reliable, compliant, and efficient hydraulic repairs and maintenance for a dedicated dredging fleet, ensuring continuous operational readiness and adherence to marine engineering standards.

Scope

The contract covers comprehensive hydraulic system maintenance and repairs for four dredging vessels: Ilembe, Italeni, Mohoma, and Isandlwana. These vessels operate dynamically across multiple South African ports, including Durban, Richards Bay, Port Elizabeth, and Cape Town, with deployment locations determined by ongoing project schedules. The scope includes hydraulic cylinder repairs, butterfly valve servicing, filter element replacement, pressure gauge installation, and flow control valve maintenance across all fleet units.

Technical Requirements

• Demonstrated experience in successfully completing hydraulic cylinder repairs within the past ten years, substantiated by a signed owner feedback letter or official completion certificate.
• Acceptance of equivalent chrome coatings and seals, provided they maintain full compatibility with vessel specifications and meet the performance demands of active dredging operations.
• Tenderers must supply all necessary scaffolding, as vessel-specific access heights cannot be predetermined by the client.
• Strict compliance with specified component parameters, including:
• Butterfly valves (DN 100–500, PN 16) featuring GGG40 or SGI bodies, aluminium bronze or CF8M discs, and NBR/H-NBR seats.
• Hydraulic cylinders with 125mm diameter pins and lengths ranging from 190mm to 300mm.
• HP return filter element (Art. No. 10768/G01068), 400 bar pressure gauge (Art. No. 12880), and ¼” stainless steel flow control valve (Art. No. 12757).
• All replacement parts must either match original manufacturer specifications or qualify as approved functional equivalents.

Skills Requirements

• Proven expertise in marine hydraulic systems, specifically cylinder rebuilding, seal replacement, and valve overhaul.
• Ability to evaluate, source, and install compatible alternative materials and components without compromising system integrity or safety.
• Proficiency in planning, erecting, and working safely with industrial scaffolding in confined marine and deck environments.
• Strong understanding of dredging vessel operational conditions, including high-pressure hydraulic circuits, abrasive slurry exposure, and frequent port-to-port mobilisation.

Explanation of Technical Terms

• PN 16: Nominal Pressure rating indicating the component is engineered to safely withstand up to 16 bar of internal pressure.
• GGG40 / CF8M / SGI: Standardised cast iron grades and stainless steel alloys selected for valve construction due to their high tensile strength, corrosion resistance, and suitability for harsh marine environments.
• Equivalent chrome coating/seals: Alternative surface hardening treatments or elastomeric sealing materials that replicate the original specifications regarding friction coefficients, wear resistance, and chemical compatibility.
• Specialist scaffolding: Custom-fabricated access structures required to safely reach and service elevated or recessed hydraulic components on large dredging vessels where standard platforms are inadequate.