Tag: Draft Survey Calculation

Inverse Draft Survey

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Few years ago, I have received the email from friend that asked regarding Inverse Draft Survey. The Inverse Draft Survey is doing when the ship has to split the cargo for two or more ports. The method is the same as common draft survey calculation, what the ship officer or surveyor needs to do is preventing cargo less or more discharge at the 1st port.

What is the purpose?
– To prevent cargo less or more discharge at one port.
– Surveyor can organize the work effectively.
– To prevent repetition of intermediate draft survey that cost a lot of time.
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Improving Accuracy of Draft Survey

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Previously has posted about the accuracy and factors effecting draft survey, check this link if you need. Now, the post below will relate to the way for improving accuracy of Draft Survey.

In draught survey operation several parties are involved and it is to advantage of each party to join the efforts to increase the accuracy. The parties involved are The buyers, the sellers, the charterers, the terminals and vessel’s staff.

Assuming that buyers, sellers and charterers are equally concerned about the correct weight of cargo, also the master (respectively chief officer to whom the responsibility of cargo weight is delegated) shortages and discrepancy may be a problem.
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Draft Survey: The Other Side

Distance Draft Mark From Perpendiculars

marine cargo ship surveyors

The above picture show you the distance of draft mark to perpendiculars. Some of you may have finds the above arrangement. But how if you find it for the first time? How do you calculate it?

Commonly in the table for draft correction, the distance of draft mark measures to the nearest perpendiculars such as;
Distance of Aft Draft Mark to Aft Perpendicular, Distance of Mid Draft Mark to Mid Perpendicular and Distance of Forward Draft Mark to Forward Perpendicular.
But the above picture shows:
The X1 is represent the Distance of Aft Draft Mark to Aft Perpendicular. (same figure)
The X2 is represent the Distance of Mid Draft Mark to Aft Perpendicular.
The X3 is represent the Distance of Forward Draft Mark to Aft Perpendicular.
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