The vessel has to be provided with approved hydrostatic and tanks sounding tables.

Means of access in order to check draft from seaside to be available.

Draft marks to be well visible, painted and its distance to the forward or aft perpendicular should be known.

Minimum possible trim and in all cases, within the corrections covered in the ship’s tank sounding tables.

To be upright in case not possible, the list must not be more than 0,5⁰.

In order to prove accurate result of the draft survey the vessel has to comply with the following: The difference between these two weights, known as net displacement, is the weight of the cargo loaded or discharged.

Vessel’s constant which generalize provisions, stores, crew, residual unknown weight etc.īriefly, the weight of the ship is determined both before and after loading/discharging and allowances made for all known deductibles.

Bunker (fuel, diesel and lubricating oils).

It is obvious that the quantity of water displaced will not only be the weight of the cargo on board but also include: ĭraft (or draught) survey is based on the Archimedes Principle, which states that anything that freely floats will displace an amount, that is equal to its own weight, of the liquid it is floating in. The matter is well known, and various articles, publications and guidelines have been issued during the years from Master Mariners, Naval Architects, P&I clubs and even from the United Nations’ Economic and Social Council. In this article, the methodology, calculation, and common errors of a draft survey will be discussed.

Determining the volume of the cargo in holds and applying the cargo stowage factor – The accuracy is questionable and this method provides no more than an approximate estimation.

Draft survey – Generally well prepared and meticulous draft survey can achieve an absolute accuracy of ☐.5%.

Various types of shore weighbridges – The accuracy is unlikely to be better than within 0.2% and in case conveyor/weigh-belt systems are used no better than ☒%.

Considering the specifics of the bulk cargo commodities, historically the industry has recognized the following methods for weight determination:

Īn essential part of each merchant sea-trade is the correct determination of the cargo loaded/discharged from/to the transporting unit.

Undoubtfully, the working horse of merchant shipping industry is the Bulk carrier’ s fleet, which with its 842 438 thousand dead-weight is forming 42,6 % of the world’s tonnage has transported 5230 million tons various bulk commodities during 2018 as per UNCTAD Review of Maritime Transport. Marine transport is the backbone of the global trade and reasonably can be considered to be the artery of the global manufacturing supply chain, as more than four fifths of the world merchandise trade by volume is carried by sea.

Draft survey calculation excel sheet