Let us have a look at them one by one:
HATCH COVER TESTS
- Hose Testing: The hose testing is to be done in an empty hold. Hatch covers to be closed and secured for sea. Powerful jet is then used on the joints etc and leaks are noted. 2 persons with walkie talkie are required. One person is to be positioned outside the hold and one inside to guide the person about the part of the hatch cover which is being hose tested. Proper lighting is required inside the hold. Hose testing cannot be carried out in freezing conditions. General manufacturers’ specifications of hose testing for steel hatch covers are as follows:
- Water Pressure: 4 bars.
- Nozzle inside diameter: 35-45 mm.
- Distance between nozzle and object: maximum 1.5 metres.
- Rate of progress: 1 metre every 3 seconds.
These specifications can differ depending upon the size of the hatch cover and the manufacturer recommendations.
- Chalk Test: Rub the chalk along the length of the compression bar and then close and secure the hatches. When opened, gaskets must be checked for chalk marks. However there are few drawbacks associated with the chalk test, which are as follows:
- Chalk mark on the gasket does not show how firm the contact with the gasket was.
- It also does not prove that compression bar stayed in contact in the final closed position.
- Ultrasonic Test: For conducting this test, dedicated equipment is required, this equipment consists of rechargeable batteries, one transmitter which is kept inside the hold, it emits the ultrasonic waves when switched on. An operator on the hatch cover takes a hand held detector on the joints and when there is a leak, it gives a sound. This instrument is to be calibrated for the range as per the cargo hold condition (whether loaded or empty). There are many advantages associated with the equipment used for this test, they are listed below:
- The test can be performed by one man.
- It will not damage the cargo.
- It can be used when temperature is below freezing.
- Reveals the exact location of the leak.
- It is accurate.
- Simple to use, requires no special training.
- It is compact and portable.
Light Test: One person has to be positioned inside the cargo hold with the hatch secured for sea and he has to observe if any light passes through, if so it indicates a leak in the hatch covers. The major disadvantage with this test is that it can only be carried out during the day time.
Visual Inspection of The Cargo Hold: Whenever there is a leak, it will be concentrated. Hence always inspect the cargo hold immediately after it is opened prior the commencement of the cargo operations. A leak can be differentiated with the sweat by keeping in mind that sweat is evenly spread over the cargo, whereas as mentioned above, leak will always be concentrated.
So, these are various hatch cover tests. We hope that you find this article hopeful. In our next article, we will cover the maintenance part of the hatch covers.
Feel free to share your views in the comments section.