Hydraulic Cylinder & Valve Package for Bulk Carrier Hatch Cover Overhaul

Project Overview

A 76,000 DWT bulk carrier undergoing special survey required a complete overhaul of the hydraulic hatch cover operating system. The existing hydraulic cylinders showed piston rod scoring and seal failure, while several control valves had internal leakage exceeding class limits.

Challenge

• 7 hatch covers × 2 cylinders each = 14 hydraulic cylinders to overhaul or replace
• 6 directional control valves with internal leakage — requiring replacement
• CCS surveyor would inspect all replaced/overhauled components
• Hatch cover system must pass weather-tightness test before vessel can trade
• Drydock period: 21 days total

Our Solution

Hicool assessed each cylinder and recommended a mix of overhaul and replacement:

• 8× New Hydraulic Cylinders — replacing units with corroded barrels (bore 160mm, stroke 1200mm, 25 MPa)
• 6× Cylinder Overhaul Kits — new piston seals, rod seals, wiper rings, O-rings for repairable units
• 6× Directional Control Valves — Rexroth-compatible, rated 35 MPa, CCS-certified
• Hydraulic Hoses & Fittings — complete renewal set, DIN standard

New cylinders were manufactured with hard-chrome piston rods and honed cylinder barrels. All components shipped with CCS pressure test certificates.

Results

• 30-day delivery — components arrived at the yard on Day 5 of drydock
• All 7 hatch covers passed ultrasonic weather-tightness test after overhaul
• CCS special survey cleared with zero observations on hydraulic system
• Combined cost of new cylinders + overhaul kits was 55% less than full OEM replacement

Key Takeaway

Hatch cover hydraulic systems don't always need complete replacement. A technical assessment to separate "replace" from "overhaul" components can save 40-50% while achieving the same class survey outcome. Hicool provides this assessment service to help owners optimize drydock budgets.