WHAT IS A DRAFT SURVEY?

WHAT IS A DRAFT SURVEY?

Draft survey is a cargo calculation method based on the determination of the ship's draft, used in the transportation of bulk cargo. It is also used in the transportation of cargoes with known weights such as containers. Draft survey can be used to control weighing operations in the transportation of cargoes with known weights such as containers. In a draft survey, if the necessary documents, booklets and tables are available on the ships, if all measurement operations are carried out correctly and completely, if the operations are directed by experienced surveyors and if meteorological conditions are suitable, the calculation of the cargo can be concluded with an error of 0.5%. Draft marks measured from a total of six points are measured accurately and honestly by the surveyor under the supervision of the ship's chief officer or the second officer assigned by him. Measurements should be made from the closest distance to the draft figures. This should be done by descending from the ship to the draft figure level with a ladder or by approaching the ship from the sea with the help of a boat. Draft numbers can be marked on the ship hull with the imperial or metric system, so the surveyor must know both the metric and imperial systems well. In the metric system, draft marks are marked 10 cm high and 10 cm apart from “0” upwards. In other words, the number length is 10 cm and the two-digit interval is again 10 cm, the line thickness is sometimes 1 cm, sometimes 2.5 cm depending on the ship, but is usually 2 cm. In the imperial system, the number length and number intervals are 6 inches, from the bottom of a number to the bottom of the number above is 12 inches, meaning 1 foot, and the line thickness is 1 inch. After the draft numbers are measured correctly and honestly from 6 points on the ship hull, the water amounts in the ship’s ballast tanks are measured according to the tank numbers, and then the water levels in the drinking and utility water tanks on the ship are measured under the supervision of the ship’s chief officer or the second officer assigned by him. After ensuring that all measurements are made correctly and honestly, the calculations are started.