How does UT hatch tightness testing work? A step-by-step guide<\/h1><\/div>UT (ultrasonic) hatch tightness testing checks whether a ship’s hatch covers are watertight.<\/strong> An ultrasonic transmitter is placed inside the closed cargo hold, and a surveyor uses a handheld receiver to ‘listen’ along the hatch seals from outside. If ultrasound escapes, so could water. The strength of the signal shows how big the gap is \u2013 and exactly where it is.<\/p>\nNew to the equipment itself? Start with what is an ultrasonic hatch cover tester?<\/a><\/p>\n<\/div><\/i>Consigue una cotizaci\u00f3n<\/span><\/a><\/div>\n\nWhy test hatch covers at all?<\/h3>\n
Water getting in through leaking hatch covers is one of the main causes of cargo damage at sea. When cargo is damaged, it often leads to large claims against owners, insurers and P&I clubs.<\/p>\n
Regular tightness testing helps ship owners, managers and surveyors find worn or damaged seals before they cause a problem. It’s also a key part of pre-loading surveys and condition surveys.<\/p>\n<\/div><\/div><\/div>
![\"Ship](\"https:\/\/www.classltd.com\/wp-content\/uploads\/2021\/10\/Hatch-covers.jpg\" "\\"Tapas")
<\/span><\/div><\/div><\/div><\/div>What is ultrasonic testing, in plain terms?<\/h3>\n
Ultrasound is sound at a frequency too high for people to hear. It travels through air, and it will pass through any gap that air can get through \u2013 even a very small one.<\/p>\n
A solid, properly sealed hatch cover blocks the sound. A damaged or poorly compressed seal lets some of it out. By measuring the sound that escapes, a surveyor can find leaks without using any water at all.<\/p>\n<\/div>
![\"CARGO-SAFE](\"https:\/\/www.classltd.com\/wp-content\/uploads\/2021\/10\/Receiver_a_1.jpg\" "\\"Receptor_a_1\\"")
<\/span><\/div><\/div><\/div>What equipment do you need?<\/h3>\n
A typical ultrasonic hatch cover testing kit includes:<\/p>\n
\n- A transmitter<\/strong> \u2013 placed inside the hold, it fills the space with a steady ultrasonic signal<\/li>\n
- A receiver<\/strong> \u2013 the handheld unit the surveyor uses on deck, showing a reading on screen<\/li>\n
- A flexible microphone and extension arm<\/strong> \u2013 to reach along seals and into awkward corners<\/li>\n
- Headphones<\/strong> \u2013 so the surveyor can hear the leak as well as see the reading<\/li>\n
- A test device<\/strong> \u2013 to check the transmitter, microphone and extension arm are working before each survey<\/li>\n<\/ul>\n<\/div><\/div><\/div><\/div>
Step-by-step: how is a UT hatch test carried out?<\/h3>\n\n- Check the kit.<\/strong> Before the survey, the transmitter, microphone and extension arm are checked to make sure everything is working correctly.<\/li>\n
- Place the transmitter in the hold.<\/strong> The hold can be empty or already loaded with cargo.<\/li>\n
- Close and secure the hatch covers.<\/strong> The covers should be in their normal sea-going condition, fully closed and cleated.<\/li>\n
- Take a reference reading.<\/strong> A reading is taken with the hatch open, known as the Open Hatch Value (OHV). This gives a benchmark to compare leaks against.<\/li>\n
- Scan the seals.<\/strong> On deck, the surveyor moves the microphone slowly along every seal, joint and cross-joint, listening through headphones and watching the display.<\/li>\n
- Find and measure leaks.<\/strong> Where ultrasound escapes, the reading rises. The higher the reading, the bigger the gap. The leak can be pinpointed to a precise spot.<\/li>\n
- Record the results.<\/strong> Readings are noted in decibels (dB) or as a percentage of the Open Hatch Value, so the results can be reported and repaired.<\/li>\n<\/ol>\n<\/div><\/div><\/div>
![\"Flexible](\"https:\/\/www.classltd.com\/wp-content\/uploads\/2021\/10\/MicroPhone_1-scaled.jpg\" "\\"MicroTel\u00e9fono_1\\"")
<\/span><\/div><\/div><\/div><\/div>How are the readings interpreted?<\/h3>\n
Readings can be shown in two ways. Decibels (dB)<\/strong> give the raw strength of the escaping signal. A percentage of the Open Hatch Value (OHV)<\/strong> compares each leak against a fully open hatch, which makes results easier to compare between holds and ships.<\/p>\nIn both cases, the principle is simple: a stronger signal means a bigger gap and a more serious leak.<\/p>\n<\/div>
Why choose ultrasonic testing over a hose test?<\/h3>\n
The traditional hose test sprays water at the hatch seals and checks for water getting through. It works, but it has drawbacks. Ultrasonic testing:<\/p>\n
\n- uses no water, so there’s no run-off into the port or harbour<\/li>\n
- can be carried out with cargo already in the hold<\/li>\n
- works in sub-zero temperatures, when hose testing isn’t practical<\/li>\n
- pinpoints the exact location and relative size of each leak<\/li>\n
- doesn’t get in the way of other work on board<\/li>\n<\/ul>\n
UT (ultrasonic) hatch tightness testing checks whether a ship’s hatch covers are watertight.<\/strong> An ultrasonic transmitter is placed inside the closed cargo hold, and a surveyor uses a handheld receiver to ‘listen’ along the hatch seals from outside. If ultrasound escapes, so could water. The strength of the signal shows how big the gap is \u2013 and exactly where it is.<\/p>\n New to the equipment itself? Start with what is an ultrasonic hatch cover tester?<\/a><\/p>\n<\/div> Water getting in through leaking hatch covers is one of the main causes of cargo damage at sea. When cargo is damaged, it often leads to large claims against owners, insurers and P&I clubs.<\/p>\n Regular tightness testing helps ship owners, managers and surveyors find worn or damaged seals before they cause a problem. It’s also a key part of pre-loading surveys and condition surveys.<\/p>\n<\/div><\/div><\/div> Ultrasound is sound at a frequency too high for people to hear. It travels through air, and it will pass through any gap that air can get through \u2013 even a very small one.<\/p>\n A solid, properly sealed hatch cover blocks the sound. A damaged or poorly compressed seal lets some of it out. By measuring the sound that escapes, a surveyor can find leaks without using any water at all.<\/p>\n<\/div> A typical ultrasonic hatch cover testing kit includes:<\/p>\n Readings can be shown in two ways. Decibels (dB)<\/strong> give the raw strength of the escaping signal. A percentage of the Open Hatch Value (OHV)<\/strong> compares each leak against a fully open hatch, which makes results easier to compare between holds and ships.<\/p>\n In both cases, the principle is simple: a stronger signal means a bigger gap and a more serious leak.<\/p>\n<\/div> The traditional hose test sprays water at the hatch seals and checks for water getting through. It works, but it has drawbacks. Ultrasonic testing:<\/p>\nWhy test hatch covers at all?<\/h3>\n
<\/span><\/div><\/div><\/div><\/div>What is ultrasonic testing, in plain terms?<\/h3>\n
<\/span><\/div><\/div><\/div>What equipment do you need?<\/h3>\n
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Step-by-step: how is a UT hatch test carried out?<\/h3>\n
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<\/span><\/div><\/div><\/div><\/div>How are the readings interpreted?<\/h3>\n
Why choose ultrasonic testing over a hose test?<\/h3>\n
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![\"CARGO-SAFE](\"https:\/\/www.classltd.com\/wp-content\/uploads\/2021\/10\/Trans_a.jpg\" "\\"Trans_a\\"")
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