Methods to Test "Weather tightness"

 There are 3 main types for testing "Weather tightness" of hatch cover:

1. Hose test
2. Ultrasonic test
3. Chalk test

Hose test:

Procedure for Hose test:

• Close and secure the hatch cover,
• A powerful jet of water taken by hose from the fire main,
• Jet should be directed towards every watertight joint in the hatch cover,
• One person will be hosing on every joint of the hatch cover and inform the second person inside the hold, which location is being tested,
• The second person will view the appropriate seam and makes a note of any leakage.

Limitations of Hose test:

• Testing only be carried out when the hold is empty.
• Cannot be carried out when the temperature is below freezing.
• Testing requires at least 2 responsible crew.
• Difficult to observer the leak in the unlit hold and if the18-20m above the observer. powerful light and binocular may be required.
• Time-consuming process.
• Scuppers should be open near the testing area and the risk of pollution.
• The test cannot show the precise point of the leak.

Ultrasonic test:

Procedure for Ultrasonic test:

• Ultrasonic equipment consists of a transmitter, where it emits ultrasonic waves when switched on,
• The ultrasonic transmitter is placed inside the hold, then close and secures the hatch cover,
• An operator on the hatch covers then takes a hand-held detector along the length of each joint in the covers,
• In any position where the seal is not tight the receiver emits audible sound and an accurate reading in decibels (dB) can be taken from the luminous display,

Advantages of Ultrasonic test:

• Can be used by one man.
• Can also be used in a loaded condition.
• Will not damage cargoes.
• Can be used when the temperature is below freezing.
• Reveals the exact location of any leak.
• Is accurate.
• Is simple to use and requires no special training.
• Is compact and portable.

Disadvantages of Ultrasonic test:

• Required class approved Ultrasonic equipment.
• Additional expense for the shipowner.
• The equipment requires regular calibration.
• The equipment is not normally part of the ship’s equipment.

Chalk test:

Procedure for Chalk test:

• Rub the chalk along the full length of the compression bar,
• Close and secure the hatch cover,
• Reopen the hatch cover and gasket must be inspected,
• On any place, no chalk mark on the gasket means no contact with the compression bar and the joint cannot be watertight.

Disadvantages of Chalk test:

• This method of testing shows where the compression bar has touched the gasket but doesn't show the compression is adequate.
• Therefore this test is not effective to check weather tightness.