PRACTICAL PROCEDURE

INTRODUCTION

The purpose of a draught survey is to determine the amount of cargo loaded or discharged for the benefit of all the interested parties. A well-conducted draught survey of a large vessel should achieve accuracy to within 0,5%.

The survey must be conducted meticulously, taking into account all the prevailing circumstances. The final report should incorporate every aspect and difficulty, which has been encountered in order to convey all aspects of the survey.

While professional surveyors may carry out draught surveys, the ship’s officers should also perform a draught survey to the same degree of accuracy. It is hoped that this guide will assist achieving the required standards.

Draught Survey

The draught survey is the “before and after” survey, which determines, by measurement, the vessel’s displacement before and after loading or discharging. The difference between these two displacements is the weight of cargo loaded or discharged.

Deadweight Survey

Under certain circumstances, the surveyor or ship’s officer may have no choice but be restricted to carrying out a deadweight survey. The weights of all measurable non-cargo elements on the vessel are determined; bunkers, fresh water, ballast, stores etc. These are then added to the light displacement (including any lightship constant). This total is then deducted from the present displacement to produce the approximate weight of cargo on board.

UN/ECE Draught Survey Code Forms

These forms have been included at the back of this information. They are the work of the United Nations Economic Commission for Europe, the Coal Working Part of the Energy Committee, which produced the Code of uniform standards and procedures for the performance of draught surveys of coal cargoes. The Working Part recommend the use of the forms in order to achieve uniformity and consistence in draught surveys, so avoiding the discrepancies which give rise to commercial disputes. The forms have been freely given, so that all surveyors and ship’s officers may photocopy and use them as a standard format throughout the industry.

PRACTICAL PROCEDURE

It is impossible to cover every conceivable problem likely to be encountered when carrying out a draught survey. Ships and Ports vary so much that there will always be the unforeseen circumstances, which will require an on-the-spot decision. These notes and steps to be taken, give only a broad approach to the subject. There is however, no substitute for experience. An inaccurate survey may result in considerable expense to several parties; therefore it should be conducted carefully and accurately. Being well prepared and having sufficient time will allow the to be conducted correctly. It may not appear expedient to delay the ship in order to complete the draught survey properly, but it could save money in the long term. This decision must be with the Master, however careful preparation could reduce these delays to a minimum. All parties should work together for a unanimous result, the facts should be established by inspection and not by verbal agreement.

1. The ship and ship’s staff must be prepared for the survey. Shore surveyors must be ready for the

Ship’s arrival.

Prior to arrival

The ship should be asked to prepare for draught survey.

The ballast tanks should be adjusted to a level covered by the sounding tables. It should be remembered that full tanks can be pressed up but still retain air pockets and also it can be difficult to establish that a tank is completely empty without visual inspection. Ballast holds, (main cargo holds used for ballast) should be empty of ballast on arrival at the loading port, if possible.

The vessel should arrive with a safe trim, suitable for the navigation to enter port and within the limits of the trim covered by the trim corrections of the sounding tables. The vessel should arrive in an upright condition.

Staff, documentation and equipment should be ready on the arrival of the ship. There should be no movement of ballast, fresh water, bunkers or cargo and hatches, cranes and moorings until all measurements are taken and agreed by surveyors and ship’s officers. The prudent surveyor will have observed the shore side draughts before boarding as these can be used to indicate any changes.

2. Examine the ship’s documentation and discuss the ship’s present condition.

Date: 2016-01-03; view: 789