What is an ultrasonic hatch cover tester?
An ultrasonic hatch cover tester is a portable kit that checks whether a ship’s hatch covers are watertight, using sound instead of water. A transmitter inside the closed cargo hold fills the space with high-frequency sound. A surveyor on deck then scans the hatch seals with a handheld receiver. Wherever sound escapes, water could get in – so the tester shows exactly where a hatch cover is leaking, and how badly.
These testers are used by marine surveyors, ship owners, superintendents and crews to find worn or damaged seals before they lead to wet cargo and costly claims.
What does an ultrasonic hatch cover tester do?
It finds gaps in hatch cover seals that could let seawater into the cargo hold. Because ultrasound passes through any gap that air can get through, even small leaks show up clearly.
The tester doesn’t just say “pass” or “fail”. It shows:
- Where the leak is – pinpointed to a precise spot along a seal or joint
- How big the leak is – a stronger signal means a bigger gap
- How it compares – readings can be shown in decibels (dB) or as a percentage of the Open Hatch Value (OHV), so results can be compared between holds and ships
Why do hatch covers need testing?
Water getting in through leaking hatch covers is one of the main causes of cargo damage at sea. Wet cargo often leads to large claims against owners, charterers and their insurers.
Hatch cover seals wear over time. Rubber packing hardens and gets damaged, and covers can distort. Regular tightness testing helps find these problems early, and it’s a key part of pre-loading surveys and condition surveys.
How does an ultrasonic hatch cover tester work?
In short:
- The transmitter is placed inside the hold – empty or already loaded with cargo.
- The hatch covers are closed and secured, as they would be at sea.
- On deck, the surveyor moves a microphone slowly along every seal and joint, watching the receiver’s display and listening through headphones.
- Where the reading rises, sound is escaping – and that’s where the leak is.
For a full walk-through, including how readings are interpreted, see our step-by-step guide to UT hatch tightness testing.
What’s in an ultrasonic hatch cover testing kit?
A typical kit includes:
- A transmitter – placed in the hold to generate the ultrasonic signal
- A receiver – the handheld unit that displays the readings
- A flexible microphone and telescopic extension arm – to reach along seals and into awkward corners
- Headphones – so the surveyor can hear leaks as well as see them
- A tester – to check the equipment is working before each survey
- Batteries, charger and a protective carry case
What else can an ultrasonic tester check?
The same technique works on any closure that’s meant to keep water out, including:
- Bow, stern and side doors
- Watertight and weathertight doors
- Access hatches
Class Instrumentation also makes DOOR-SAFE™, designed specifically for testing watertight doors.
Is it better than a hose test?
The traditional hose test sprays water at the hatch seals to see if any gets through. It works, but it has drawbacks. Ultrasonic testing:
- uses no water, so there’s no run-off into the port
- can be done with cargo already in the hold
- works in sub-zero temperatures, when hose testing isn’t practical
- pinpoints the exact location and relative size of each leak
For a fuller comparison, see ultrasonic vs hose testing: which hatch cover leak test is best?
What other names are used for this equipment?
You may see ultrasonic hatch cover testers described as:
- hatch checkers or hatch leak detectors
- ultrasonic watertight integrity testers
- UT tightness testing devices
- ultrasonic hatch leak testers
They all describe the same basic idea: using ultrasound to check that hatch covers and doors are watertight.
What should you look for when choosing one?
Surveyors and ship operators usually look for:
- Type approval from a recognised classification society, such as ABS
- Compliance with IACS UR Z17, which covers firms carrying out tightness testing of hatch covers
- A powerful transmitter that can fill even the largest holds
- Rugged, weatherproof construction for use on deck in all conditions
- Long calibration life and ongoing technical support
About CARGO-SAFE™
CARGO-SAFE™ is an ultrasonic hatch cover tester designed and made in Britain by Class Instrumentation. It is ABS Type Approved and complies with IACS UR Z17. Its 157 dB transmitter is powerful enough for any size of hold, its units are protected to IP66, and it is factory-calibrated with a predicted calibration life of five years.
For extra capability, see CARGO-SAFE PLUS™.