Chalk testing is used traditionally for visual inspection of the compression integrity of doors and hatches on vessels that hold the potential for flooding. Chalk is applied evenly around the knife edge, coaming compression bars or panel cross seams of doorways. The door/hatch is then closed and sealed. Once re-opened the rubber gasket which pushes against the knife edge is visually inspected for the chalk line. Any breaks in the chalk line indicate a lack of compression in that area. It must be noted that chalk testing is NOT a leak test, but only provides an indication of potential compression issues
The International Association of Classification Societies states that a chalk test must be followed by a hose test. The hose test is used in conjunction to determine the weather tightness of doors and hatch covers testing. The spray from a nozzle of 12mm diameter is sprayed from a distance of 1 to 1.5 meters with a water jet pressure of 0.5 This test should help identify any leakage from the hatch joints, although the exact location of the leakage sight cannot be pinpointed.
Why are these methods no longer recommended by P&I clubs?
Various drawback come with chalk and hose testing, for instance;
Both of these tests are time-consuming and sometimes completely impractical. Some circumstances have been highlighted that prevent this test from being conducted such as the hose test if dry cargo is within the hold being tested but these tests conducted at port or in dry dock will never reproduce conditions when the ship is at sea and therefore cannot expect to achieve the same standard. Claims resulting from water damage due to leaking hatch covers still contribute a huge part of the overall loss figures on dry cargo ships. This method is neither accurate nor time effective.
What is the alternative?
The Swedish P & I club recommend using Ultrasound. As stated in their 2018 report “A much more effective method is to use an ultrasonic device, which is designed for this purpose and can pinpoint the area which is leaking, and if the compression of the gasket is sufficient. The advantages of using this type of equipment are evident, since ultrasonic tests can be carried out during any stage of the loading without risking cargo damage. The test can also be completed in sub-zero temperatures. The ultrasonic test should be carried out as per the class requirements.”
Ultrasonic testing is a dramatically more sensitive, accurate and reliable method for testing cargo hatch covers, bulkheads and doors for watertight integrity on all vessels. A multi-directional ultrasound emitter is placed in a hold. The opening being tested is then sealed and the receiver switched on ready to receive any leakage of ultrasound via a set of headphones. An increased reading of ultrasound signal signifies an issue with the integrity of the door/hatch. Further, and closer inspection will allow identification of any specific leakage sight along with the severity. This test will take approximately 10 minutes and requires only one operator.
Which is the best ultrasonic test kit for hatch cover testing?
Owners, managers, marine surveyors, third party servicing companies and other mariners have pledged their support for the Portascanner® WATERTIGHT for years.
For 3 simple reasons: “it is faster, better, cheaper” than any competitor. But don’t take Coltraco Ultrasonics’ word for it, here are 3 customer testimonials:
“We did some transit inspection work on one of our customers vessel using the Portascanner and we are very pleased with your instrument. We are looking forward extending our service offer using it.” – Techsol Marine, Canada
“The fleet was equipped with a unit per Bulk Carrier and the units are and working well, providing the confidence that there will be no problems with water damage claims.” Ship Management Company
“Our PORTASCANNER WATERTIGHT unit performed well during the entire period of use, proved rugged and we feel sure that if it had not required returning for mandatory calibration and certification, the unit would have performed well for many more years to come.” Captain J.F. Holmes, Botrans
The Portascanner® WATERTIGHT is:
The Portascanner® generator is the most efficient of all on the market. Unlike the old “Hedgehog Generator”, the Portascanner® generator has excellent battery life, is light and small, has magnetic mount, is highly sensitive and uses smart pinpoint technology to direct ultrasound to the seals during testing.
Coltraco Ultrasonics’ mission delivering Safeship® solutions to improve safety of life, assets and vessels at sea. They do by manufacturing high quality British instrumentation, supplied to over 100 countries worldwide, since 1987. Coltraco Ultrasonics focus on benefitting the crew; designing innovative ultrasonic solutions which the crew will be happy to use by being easy to operate, quick, accurate and a better method to traditional techniques. Thus increasing the likelihood of tests being regularly conducted, in line with regulations and even going above and beyond for more frequent testing. By so doing, the crew will be creating a safer ship.
Discover more about Coltraco Ultrasonics’ commitment to customer care and safety on www.coltraco.com.
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