With a draft survey, we can determine the weight of cargo on board the vessel by measuring the displacement of the water before and after (un)loading. The resulting difference represents the weight of the designated cargo. A survey is performed by reading the vessel’s draft markings at six standard points on the hull: forward, midship, and towards both the port and starboard sides. Revisions for factors such as trim, water density, and non-cargo weight (such as fuel oil and drinking water) are part of the calculation that we perform. The accuracy of a weight determined by draft survey also depends upon the sea conditions (pitch and swell) at the time of loading or discharge.
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A survey is performed by reading the vessel’s draft markings at six standard points on the hull: forward, midship and towards both the port and starboard sides
Revisions for factors such as trim, water density and non-cargo weight (such as fuel oil and drinking water) are made before calculating the cargo weight change
Our highly-qualified professionals have extensive experience in this service and are available 24/7 to perform a draft survey and produce an independent report using the Control Union Draft Survey Software System, based on the internationally standardized draft survey protocol. This program calculates the loaded or discharged weight and a signed quantity agreement will be handed over to the chief officer with the draft survey report sent to the relevant parties.
When draft surveys are initiated by independent surveyors, cooperation of the ship’s officers is essential. Independent surveys should be undertaken together with the vessel’s chief officer and chief engineer or their appointed deputies, during the relative survey sections.
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