Inspection of draft and practical experience
Drafting is one of the most important jobs in shipping goods by waterway. Let Lec learn about the outline of draft and practical experience through the following article.
Draft inspection is a method to determine the weight of goods on the vessel, in which the displacement of water before and after loading (unloading) the goods will be measured and the difference obtained represents the weight of designated goods.
1. Determine the volume of goods
First we read the draft (including left and right noses. Between left and right. Left and right steering). Then we calculate the average draft. Nasal draft = left nose + right nose 2. similar to middle draft and drive.
Correction due to the draft reading does not coincide with the waterway. Then we calculate the average draft = ((nose tip + steering wheel) * 2 + middle median) divided by 4
Checking the hydraulics table will give us the volume of the ship in the sea (density 1.025) :( D). Use the hydrometer to measure the density of water at the place where the vessel is anchored (td). Then the actual ship volume = D * td divided by 1,025.
2. Experiences in reading large water
The accuracy of the draft reading is influenced by many factors such as the accuracy of the draft, the extent of the waves, the curvature of the hull where there is a measure of draft, light when observing, engineering and experience of reading draft ... In order to improve the accuracy of the draft reading, attention should be paid to the following points:
2.1. Read when the water is quiet
Try to get as close to the draft as possible.
The lower the visibility, the better the water surface.
Use tape measure to support when measuring (water surface must be absolutely quiet)
When reading draft in poor lighting conditions (night time), the following measures must be applied to improve accuracy, throw a pebble to create waves near the draft, or drop objects. Light on the water surface, the goal is to make the waterline bobbing lightly at the barometer, using a powerful light flashlight to read.
2. When there are small to medium waves
When waves are best, stand on the jetty or use canoes to read the draft. However, when using canoes, pay attention not to run too close to the vessel so that it is possible to see the barometer without creating big waves, making it difficult to observe.
Each observation attempted to read the reading at the midpoint of the wave crest and the wave bottom. Read many times to get the average value.
The draft measure must be read at the foot of the digit indicated on the draft.
In general, in any case when reading a draft, loosen the anchor chain and adjust the line so that they do not affect the vessel's draft.
By experience and close links with leading experts in the field of maritime inspection, LEC GROUP will help your sea freight transactions become convenient, easy to manage the volume of goods, reduce risks, and offer various solutions to bring confidence to customers.