Hull thickness and NDTLesson 4 of 5
Hatch cover weathertightness and ultrasonic tightness testing
You will be able to plan and witness a hatch cover tightness test, read ultrasonic results against the open hatch value, and recognise the defects no test will show.
15 minutes · For signed-up learners, free · Rules checked 20 October 2026
Start here
A few litres of seawater through a hatch cover joint will not sink a ship, but they can turn a hold of grain, steel coils or paper into a cargo claim. IACS says it plainly in its guidance to owners: loss of weathertight integrity “continues to be a constant factor leading to cargo damage”, and class and load line survey reports contain “frequent references” to poorly maintained hatch covers. In 2025 Paris MoU inspectors recorded 2,637 deficiencies under the Load Line Convention, the regime that covers hatchways and their covers.
The hatch cover is also structure. On bulk carriers the forward covers take green seas, and a cover that lifts or leaks can flood a forward hold. That is why every special survey requires the sealing of all hatch covers to be proved, by hose test or an equivalent such as an ultrasonic test, and why the firms doing ultrasonic tests for class must be approved. Walk the hatch below and tick what is wrong.
Continue this lesson free
The rest of this lesson, the interactive Ultrasonic tightness test of No. 1 hatch cover, bulk carrier and the quiz are open to signed-up learners. It's free, takes a minute, and opens every lesson in all 14 courses.
In this lesson
- Try it: Ultrasonic tightness test of No. 1 hatch cover, bulk carrier
- In plain words
- In detail
- What the rules say
- Flag and class notes
- Key numbers
- What inspectors find
- Questions people ask
- Quiz: 6 questions
Sources
- 1 IACS Recommendation No. 14, Hatch cover securing and tightness, Rev.2 Corr.1 (October 2005), paragraphs 2.2.2, 3.1.1, 3.2, 4.1.2, 4.1.4, 4.1.5, 4.2.2 and 6.1 to 6.3. https://iacs.s3.af-south-1.amazonaws.com/wp-content/uploads/2022/05/19141052/rec_14_pdf177.pdf
- 2 IACS Recommendation No. 15, Care and survey of hatch covers of dry cargo ships: guidance to owners, Rev.3 (August 2013), paragraphs 1.1 to 1.4, 2, 3.3, 3.4, 4.1, 4.3, 5.4, 6.1 and 6.1.5. https://iacs.s3.af-south-1.amazonaws.com/wp-content/uploads/2022/05/19141142/rec_15_pdf178.pdf
- 3 IACS Unified Requirement Z7, Hull Classification Surveys, Rev.29 Corr.1 (May 2024), paragraphs 2.2.10, 3.2.3 and Table 1. https://iacs.s3.af-south-1.amazonaws.com/wp-content/uploads/2024/05/21130428/UR-Z7Rev.29Corr.1.pdf
- 4 IACS Unified Requirement Z10.2, Hull Surveys of Bulk Carriers, Rev.37 (February 2023), paragraphs 2.2.4 and 3.2.3.2 to 3.2.3.7. https://iacs.s3.af-south-1.amazonaws.com/wp-content/uploads/2023/08/10152246/ur-z102rev37.pdf
- 5 IACS Unified Requirement Z17, Procedural Requirements for Service Suppliers, Rev.21 (January 2025, implemented from 1 July 2026), paragraphs 4.1.2, 4.2, 5.2.11 and Annex 1, section 2. https://iacs.s3.af-south-1.amazonaws.com/wp-content/uploads/2023/05/14135618/UR-Z17-Rev.21-Jan-2025-CLN.pdf
- 6 North of England P&I Association, Loss Prevention Briefing: Hatch Cover Testing (2011), sections on hose tests, ultrasonic tightness testing and comparison of methods. Industry guidance, not a rule.
- 7 IACS Unified Requirement S21, Evaluation of Scantlings of Hatch Covers and Hatch Coamings and Closing Arrangements of Cargo Holds of Ships, Rev.6 (January 2023), section 7.2. https://iacs.s3.af-south-1.amazonaws.com/wp-content/uploads/2023/08/10144821/ur-s21rev6.pdf
- 8 Paris MoU on Port State Control, Annual Report 2025 (published 1 July 2026), Major categories of deficiencies 2023-2025. https://parismou.org/year-report/year-report-2025/
Free awareness training. Al Safwan Marine is not an approved training provider, so no certificate is given, and these courses are not a qualification. They don't replace STCW training, manufacturer training or the certification technicians need for this work. The manufacturer's manual and your flag's rules always come first.
Sign in to save your progress.
This lesson is also published by our sister site vslsafety.com.
