Hatch Cover Ultrasonic Tightness Testing
in Hong Kong.

Ultrasonic hatch cover testing

Ultrasonic tightness testing finds leakage paths in hatch-cover sealing systems without flooding the deck with a hose test. A transmitter is placed inside the cargo hold and an operator scans the closed perimeter with a calibrated receiver. Changes in the measured signal identify compression faults, damaged gaskets, distorted panels, leaking cross-joints, drains, cleats, access hatches, or other openings. The method is fast, repeatable, and suitable for condition surveys, pre-loading checks, maintenance planning, and post-repair verification.

Survey and acceptance context

Class societies, P&I clubs, cargo interests, charterers, and marine surveyors may request an ultrasonic test where weathertight integrity is in question. Testing is commonly performed by a service supplier operating under recognised procedures, with equipment calibrated before and after attendance. Acceptance criteria and permissible leakage levels depend on the test standard, instrument, class or P&I instruction, and the purpose of the survey. The attending surveyor or instructing party determines whether the result can replace or supplement a hose test.

Typical scope and deliverables

• Visual review of panels, compression bars, gaskets, cross-joints, drains, non-return valves, cleats, and landing pads
• Baseline and open-hatch readings followed by a systematic closed-hatch scan
• Marking and photographing individual leak locations for the repair team
• Repeat testing after gasket renewal, adjustment, welding, or other rectification
• A hatch-by-hatch report showing equipment details, calibration, weather conditions, readings, findings, and test conclusion

Requesting attendance

Send the vessel and port, hatch type and maker, number and dimensions of holds, reason for testing, required standard, previous report, known defects, and surveyor or P&I instructions. Confirm safe hold access, hatch operation, cargo condition, electrical restrictions, and whether repairs or retesting may be required during the same call. This information helps select the right equipment and reserve enough time for a complete, defensible test record.

Test method and common questions

Is ultrasonic testing accepted instead of a hose test?

It may be accepted for a particular class, P&I, charterer, or condition-survey purpose when performed with suitable equipment and procedure. It does not automatically replace every statutory test. The instructing surveyor should approve the method and acceptance criterion in advance, especially after major steel repairs or where a rule explicitly calls for another test.

What does a percentage reading mean?

The receiver reading is interpreted against an open-hatch reference established with the transmitter and instrument. It is not a direct opening size or a universal pass value. Instrument characteristics, hold geometry, background noise, and the agreed procedure matter. Reports should state the baseline and criterion instead of presenting isolated percentages without context.

Can a loaded hold be tested?

Testing normally requires safe placement of the transmitter and a controlled signal inside the hold. Cargo, closed access, hazardous atmospheres, or terminal restrictions may prevent that. Some limited arrangements are possible only after a competent risk assessment and agreement with the instructing party. Never enter or introduce equipment into a space without vessel authorisation and atmosphere controls.

Which repairs commonly follow a failed test?

Typical corrections include cleat adjustment, gasket renewal or partial insert repair, compression-bar restoration, drain cleaning, non-return-valve service, landing-pad adjustment, and steel repair to distorted panels or cross-joints. The correct repair follows the hatch maker’s tolerances and material guidance. Retesting should cover repaired points and adjacent sealing sections before completion evidence is issued.