Case Study: Offshore Support Vessel Hatch Seal Replacement
Technical Case Study | Last Updated: March 2026
Executive Summary
When a North Sea platform supply vessel required comprehensive hatch seal replacement during its 5-year special survey, the operator faced OEM quotes exceeding £180,000 with 12-week lead times. Rubber Strip UK delivered a complete aftermarket solution in 5 days at £68,000, achieving full DNV classification compliance and eliminating water ingress issues that had plagued the vessel for 18 months.
The Challenge
Vessel Background
The 2015-built PSV operates year-round in the Central North Sea, supporting drilling and production platforms. Continuous exposure to salt spray, UV radiation, and temperature cycling from -10°C to +35°C had degraded original hatch seals beyond serviceable condition.
Documented Issues
- Cargo hold hatches: Water ingress during heavy weather, damaging deck cargo
- Engine room vents: Salt water contamination of intake air
- Accommodation doors: Draughts and water penetration in crew quarters
- Bridge windows: Seal deterioration causing condensation and visibility issues
Classification Requirements
DNV Special Survey required all weathertight closures to pass hose testing at 2 bar pressure. Pre-survey inspection identified 34 of 47 hatches failing this requirement.
The Solution
Material Specification
Marine applications demand exceptional material performance. Our specification process prioritised:
| Requirement | Specification | Material Selected |
|---|---|---|
| Salt water resistance | Continuous immersion rated | EPDM (excellent) |
| UV stability | >10 years outdoor exposure | EPDM with UV stabilisers |
| Temperature range | -20°C to +80°C | EPDM (-40°C to +120°C) |
| Compression set | <20% after 1000hrs | 70 Shore A compound |
| Flame retardance | IMO FTP Code compliant | FR-EPDM grade |
Products Supplied
- Hollow D-section seal (320m): Primary hatch compression seal, 25mm x 20mm profile
- P-section lip seal (180m): Secondary weathertight doors
- Glazing gasket (45m): Bridge and accommodation windows
- Sponge EPDM strip (90m): Vent louvre sealing
- Corner mouldings (94 pieces): Pre-formed 90° corners for hatch frames
Installation
Rubber Strip UK provided on-site technical support for the 5-day installation:
- Day 1-2: Cargo hold hatches (12 units) - largest and most critical
- Day 3: Engine room and machinery space closures (18 units)
- Day 4: Accommodation weathertight doors (11 units)
- Day 5: Bridge windows, testing, and DNV inspection
Results
Performance Metrics
| Metric | Before | After | Improvement |
|---|---|---|---|
| Hatches passing hose test | 13/47 (28%) | 47/47 (100%) | +72% |
| Water ingress incidents | 8/month avg | 0 | Eliminated |
| Cargo damage claims | £34,000/year | £0 | Eliminated |
| DNV compliance | Conditional | Full | Restored |
Cost Comparison
| Option | Cost | Lead Time | Notes |
|---|---|---|---|
| OEM replacement seals | £184,000 | 12 weeks | Original manufacturer |
| Alternative shipyard quote | £142,000 | 8 weeks | Generic marine seals |
| Rubber Strip UK solution | £68,400 | 5 days | Custom profiles, on-site support |
| Saving | £115,600 | 11+ weeks | 63% cost reduction |
Technical Insights
Why EPDM for Marine?
EPDM outperforms neoprene in marine weatherseal applications despite neoprene traditionally being considered the marine standard. Key advantages:
- Superior UV resistance (critical for exposed deck fittings)
- Better low-temperature flexibility (North Sea winter conditions)
- Equivalent salt water resistance
- Lower compression set over time
Corner Solution
Traditional corner joints are the primary failure point for hatch seals. Our solution used pre-moulded vulcanised corners bonded to straight sections, eliminating the weak point of site-made corner joints.
🚢 Products Featured in This Project
- D-Section Hollow Seals - Hatch compression sealing
- P-Section Lip Seals - Weathertight doors
- Glazing Gaskets - Window sealing
- Sponge EPDM Strip - Vent sealing
Marine project enquiry? Contact our technical team for material recommendations and custom profile development.
Case study prepared by Rubber Strip UK Technical Department, March 2026.