Cargo Hatch Covers – An Important Part for Determining a Cargo’s Worth

A cargo ship has many cargo spaces where it stores the cargo. All cargo spaces have sturdy and heavy lids, called hatch covers to cover storage spaces.

Proper protection of Cargo store places ensures safety to the cargo containers and avoids any wastage. It has to be watered and airtight for preserving the cargo goods during long journeys. In the case of perishable goods, it becomes necessary to save them from humidity and bad climatic conditions.

Failing will only lead to wastage of goods and also possibilities of contamination which could lead to diseases. A Hatch cover can prevent such situations and could collate to the lids on a box.

Types of Hatch Covers

The ultimate purpose of the hatch cover is to avoid water entering the cargo space. It protects the goods from getting wet and damaged.

Let’s get to know about the popular types of hatch cover:

1. Folding Type Hatch Covers

Folding type hatch covers are managed with hydraulic arms to control multiple flat-shaped panels. These hatch covers can support both tweens as well as weather decks. The main benefit of these folding hatch covers is their large size. A bigger size of hatches means lesser panels on the hatch covers.

2. Rolling Type Hatch Covers

Rolling type hatch covers use rollers that fold inside the holder installed at the ends of the hatch covers. Wheels help in sliding the panels either sideways or lengthways. Rolling-type hatch covers are a preferred choice in larger ships. They are very heavy and have larger dimensions, and hence, hydraulic rams operations lift them.

3. Lifting Type Hatch Covers

Lifting type hatch covers have two broad categories, namely, single panel and multi-panel covers.

The single panel has a single lid for each cargo space and has preferred use in bulk cargo vessels. Likewise, multi-panel covers have multiple lid covers to cover a single cargo space.

4. Stacking Type Hatch Covers

Vessels that use stacking-type hatch covers have small hatch holds. It has a hydraulic lifting crane that lifts the hatch covers and puts them on top of each other at one end. These are a cheaper option and preferred choice in barges.

Hatch Covers Maintenance

Quality hatch covers use lightweight and durable steel material. They are placed over the steel slabs of the cargo space with a rubber pack between them. The rubber packs ensure that water does not enter the hold.

• A trained expert should handle the hatch cover maintenance, and it must have:
• A complete examination of the hatch cover includes material failure, corrosion, and cracks.
• Maintain rollers, blocks, haulage wires, and wedges functional all the time.
• Check if hatch cover tops are clean and drainage exits are clear.
• Replace missing or broken gasket, if any. The replaced gasket should be of minimum 1m.
• The Hatch cover should be checked from steel to steel for faults before replacing the rubber gasket.
• Do greasing to all the functional parts.
• Perform an oil test for hydraulic parts.
• The surveyor should manage the vital repairs in the hatch covers.

Hatch Cover Testing

Once the maintenance procedure completes, then the testing of water and air tightness is performed. Following are the types of hatch cover tests to check its water and airtightness:

1. Hose Water Test

In this test, water is shot over the joints of the hatch cover. It is done from a 1-meter distance with a force of 0.5 m/sec. The limitation of hose water testing is that it needs two people, and the hatch cover should be empty. Minor leaks get unnoticed in this test. Also, performing this test in chilling weather is not possible.

2. Ultrasonic Testing

It is a better and more correct testing procedure of the hatch cover. In this test, a UT generator is placed inside the cargo space. The sensor passes through the hatch joints, and if low pressure is detected anywhere, it can be a leak point.

The major drawback of UT testing is that it requires a trained person to do the test.

3. Chalk Test

The chalk test is the oldest type of hatch cover testing, but it cannot find the reliability of the water-tightness of the hatch cover.

In this test, chalk dust gets applied to the backside of the hatch cover, and then it is closed tightly. The gap in chalk dust markings on the rubber packing symbolize low-pressure areas in the hatch.

Hatch Cover Testing is Required

Improper maintenance of hatch covers could lead to water getting inside the cargo holds. Tests performed to check the water-tightness of hatch covers, are the foremost requirement to prevent any damages to cargo goods and the vessel.

Timely maintenance and proper testing of the hatch covers could enhance the vessel’s cargo worthiness. If considered legally and as per the International Convention on Load Lines, the hatch covers should be secured, tight, and strong. It helps the hatch covers to be watertight and resist the oceanic nature.