Vessel · Marine
Double Hull
Two layers of steel around the cargo tanks, with an empty or ballast space between them, so a grounding or collision is less likely to spill oil.
What it does
Under MARPOL Annex I, oil tankers of 5,000 deadweight tons and above ordered after 6 July 1993 must have a double hull or an approved alternative. Single hull tankers were phased out on an accelerated schedule.
Basics
| Rule | MARPOL Annex I, regulation 19 |
| Applies to | Oil tankers of 5,000 dwt and above |
| Space between hulls | Used for segregated ballast |
Common failures
- Corrosion in the ballast spaces between the hulls
Troubleshooting
- Symptom
- Coating breakdown found in ballast tanks
- Likely cause
- Corrosion in the wet, hard to reach spaces
- What to check
- Inspect and repair coatings at each survey