Hatch Cover Testing

What is Hatch Cover Testing?

Hatch covers are essential to cargo ships, ensuring the safe transport of goods across the world’s oceans. The hatch covers are designed to withstand rough sea conditions and protect the cargo from damage due to water ingress.

However, these covers’ reliability depends on regular and thorough testing to ensure they function as designed. This article will explore the process of hatch cover testing and its significance in the shipping industry.

Purpose of Hatch Cover Testing

The hatch cover testing aims to evaluate the covers’ structural integrity and water-tightness, ensuring that they function correctly and protect the cargo during transit. This is crucial in ensuring cargo ships’ safe and efficient operation. The testing process provides valuable information on the performance of the covers, allowing for any necessary repairs or replacements to be made before the covers are put into service.

The purpose of hatch cover testing can be broken down into several key objectives:

1. To evaluate the strength and stability of the covers: The covers must be able to withstand the forces exerted on them by rough sea conditions, as well as the weight of the cargo. Testing helps to determine if the covers can meet these requirements.
2. To evaluate the water-tightness of the covers: The covers must keep water out of the cargo hold, even in heavy rain or high waves. Testing helps determine if the covers can maintain a watertight seal.
3. To identify potential weaknesses or defects: Testing helps identify any areas of the covers susceptible to damage or failure, allowing for necessary repairs or replacements.
4. To comply with regulations: Many countries require cargo ships to undergo regular hatch cover testing. These regulations are in place to ensure the safety of the cargo, crew, and ship.

The hatch cover testing aims to ensure the function of the cover correctly and protect the cargo during transit. The shipping industry can maintain the highest safety and efficiency standards by regularly testing the covers.

How Does Ultrasonic Leak Detection Work?

Ultrasonic leak detection takes advantage of fundamental characteristics of sound waves to identify and precisely locate water leaks in any structure. It makes use of the reflection and absorption behaviour of sound waves when incident on a boundary between a solid structure and the air adjacent to it.

Ultrasonic leak detectors are composed of two main components: an ultrasound generator and a receiver unit. The generator is placed on one side of a structure and switched on, filling the room or compartment with ultrasound. The receiver is then deployed on the other side of the structure to scan for leaks.

When no leak is present, the ultrasound is reflected or absorbed by the structure and so no ultrasound is detected by the receiver. When the receiver wand is pointed towards a leak, ultrasound is detected as it is able to propagate through the leak path. The reflection and diffraction of the sound wave as it passes through the leak path are affected by the size and shape of the leak, meaning information about the size and shape of the leak can be interpreted by the receiver unit.

Hatch Covers Common Applications

The Portascanner® range has a proven track record in a number of industries and applications:

• Shipping/Marine
• Defence/Naval

• Oil & Gas
• Hatch Covers
• Watertight & Weathertight Doors
• Multiple Cable Transits

Meets Classification Society Requirements

The Portascanner is designed to meet Classification Society requirements for watertight integrity type of test equipment. The two most relevant Classification Society requirements are DNVGL-CP-0484 and IACS UR Z17.

DNVGL-CP-0484 relates to the service supplier (the company conducting the ultrasonic watertight integrity test) and also lists the exact requirements of the equipment that needs to be used by such service suppliers for ultrasonic watertight integrity testing to comply with the standards. This is in Page 13 and 14 (Chapter 2).

Extract from the requirements as below, and the Portascanner complies with all these:

• The transmitter shall provide a uniform open hatch value (OHV) over the tested area
• OHV shall be adjustable to a stable value allowing maximum sensitivity without false side effects
• The receiver shall be provided with an audible signal and a visual readout, calibrated in decibel
• Biannual re-calibration tests shall be carried out by laboratories authorised by the manufacturer
• Fail/pass criterion to be applied in tightness testing:
• 0 dB hatch cover is leak tight
• 1 dB to 10% OHV shall mean that the hatch cover is considered weathertight
• Above 10% OHV shall mean the hatch cover is considered not to be weathertight

Regulation Compliance for Hatch Cover Tests

There are multiple regulations pertaining to watertight/weathertight integrity inspections which are made easier with Portascanner:

SOLAS Chapter XII – Additional safety measures for bulk carriers – Regulation 7 – Survey and maintenance of bulk carriers

Bulk carriers shall comply with the maintenance requirements provided in regulation II-1/3-1 and the Standards for owners’ inspection and maintenance of bulk carrier hatch covers

Resolution MSC.169(79) Standards for owners inspection and maintenance of bulk carrier hatch covers

2.5 Ship owners and operators shall keep a Maintenance Plan and a record of maintenance and component replacement carried out, in order to facilitate maintenance planning and statutory surveys by the Administration. Hatch cover maintenance plans shall form part of a ship’s safety management system as referred to in the ISM code.

SOLAS II-1 Part B-4 Stability Management – Regulation 21 – Periodical operation and inspection of watertight doors, etc., in passenger ships

3. The watertight doors and all mechanism and indicators connected therewith, all valves the closing of which is necessary to make a compartment watertight and all valves the operation of which is necessary for damage control cross connections shall be periodically inspected at sea at least once a week

SOLAS II-1 Part B-4 Stability Management – Regulation 13-1 – Openings in watertight bulkheads and internal decks in cargo ships

Where penetrations of watertight bulkheads and internal decks are necessary for access, piping, ventilation, electrical cables, etc., arrangements are to be made to maintain the watertight integrity.

SOLAS II-1 Part B-4 Stability Management – Regulation 13 – Openings in watertight bulkheads below the bulkhead deck in passenger ships

1. Where pipes, scuppers, electric cables, etc., are carried through watertight bulkheads, arrangements shall be made to ensure the watertight integrity of the bulkheads

SOLAS II-1 Part B-4 Stability Management – Regulation 11 – Initial testing of watertight bulkheads, etc.

1. Where a hose test is not practicable because of possible damage to machinery, electrical equipment insulation or outfitting items, it may be replaced by a careful visual examination of welded connections, supported where deemed necessary by means such as a dye penetrant test or an ultrasonic leak test or an equivalent test. In any case, a thorough inspection of the watertight bulkheads shall be carried out. 

For More Information on Hatch Cover Testing, Contact Coltraco Ultrasonics Today

Hatch cover testing is an essential aspect of the shipping industry, ensuring the safe transport of goods across the world’s oceans. The various ultrasonic tests performed on the covers provide valuable information on their performance, allowing for necessary repairs or replacements before they are put into service. Regular testing is critical to the safety of the cargo, crew, and ship, and the shipping industry must prioritise this vital process.

For more information, contact the team at Coltraco Ultrasonics today.

Hatch Cover Testing FAQs

What are the methods for leak testing of a ship’s hatch cover?

The main methods for leak testing are ultrasonic testing, chalk testing and hose testing.

Ultrasonic Testing: This method involves using ultrasonic equipment to detect air leakage through gaps or defects in the hatch cover seals. Ultrasonic waves are emitted, and the equipment measures the time taken for the waves to return after bouncing off surfaces, identifying areas of leakage.

Chalk Testing: Chalk is applied along the hatch cover seals, and the hatch is closed. After reopening the hatch, any smudges or breaks in the chalk line indicate potential leakage points.

Hose Testing: A high-pressure hose is used to spray water onto the closed hatch cover seals. Any water ingress or leakage observed on the inner side of the hatch indicates potential seal failures.

What are the three types of hatch covers?

The three types of hatch cover commonly used on ships are:

• Folding hatch covers
• Rolling hatch covers
• Lift-away hatch covers

Why is inspection of hatch cover important prior to leaving the berth or port?

Inspecting hatch covers prior to leaving the berth or port is crucial to ensure the vessel’s safety and cargo protection during the voyage. By conducting a thorough inspection, any issues with the hatch covers, gaskets, or securing mechanisms can be identified and rectified before encountering adverse weather conditions or rough seas. This proactive approach minimises the risk of water ingress, cargo damage, and compromises to the vessel’s stability.

Why is it crucial to monitor the watertight integrity of a ship’s hatches, fittings, and seals?

Monitoring ensures the vessel remains afloat, protects cargo, and contains any water ingress, preventing catastrophic incidents that could endanger the ship and its crew. It also helps comply with safety regulations and standards, minimizing the risk of accidents and ensuring the ship’s seaworthiness for safe navigation.

What is IACS Mandate Z28, and why is it significant?

IACS Mandate Z28 mandates the examination of cable transits on ships to confirm their satisfactory condition. This is significant because cable transits are recognized as key failure points in maritime incidents, impacting vessel safety and operation. Compliance with this mandate helps enhance ship safety and reduces the likelihood of incidents due to cable transit failures.

What are some notable maritime incidents caused by failures in watertight integrity?

Examples include the grounding of HMS Nottingham, the flooding of the Emma Maersk, and the sinking of HNoMS Helge Ingstad. These incidents illustrate the severe consequences of compromised watertightness in ships, leading to financial losses, environmental damage, and risks to crew safety. Proper watertight integrity management could have prevented or mitigated these incidents.

Why is ultrasonic watertight integrity testing preferred over conventional methods?

Ultrasonic testing offers accuracy and reliability without causing damage to the vessel or its cargo. Unlike outdated methods like the Chalk Test or Hose Test, ultrasonic verification provides a non-invasive solution for detecting leaks effectively. It allows for precise identification of leak points, enabling timely maintenance and repair actions to maintain watertight integrity and prevent potential hazards.

How does the Portascanner® WATERTIGHT PLUS facilitate efficient watertightness testing?
The Portascanner® WATERTIGHT PLUS provides a handheld, portable solution for detecting leaks as small as 0.06mm in diameter. With its user-friendly design, a single operator can conduct fast and reliable monitoring, minimizing risks associated with water ingress during maritime operations. Its high sensitivity and accuracy make it an essential tool for ensuring the safety and integrity of ship structures.