Section 7 Testing

7.1.1 Each ballast tank, oil tank, fresh water tank and cofferdam is to be tested by a combination of leak tests and structural tests as outlined in Pt 2, Ch 1, 7.2 Leak tests and Pt 2, Ch 1, 7.3 Structural tests.

7.1.2 For testing of other items, if fitted, see Pt 3, Ch 1, 9 Procedures for testing tanks and tight boundaries of the Rules and Regulations for the Classification of Ships, July 2022.

7.2.1 Each ballast tank is to be tested for leaks by means of a soapy solution examination while the tank is subjected to an air pressure of 0,14 kgf/cm². It is recommended that the pressure in the tank be raised to 0,21 kgf/cm² with the minimum number of personnel in the vicinity of the tank, and then lowered to the test pressure before the examination commences. Precautions are to be taken to prevent excess pressure by the introduction of a relief valve or water gauge. Air testing is normally to be carried out before a protective coating is applied. However, subject to careful inspection by the Surveyors, a complete protective coating may be applied prior to air testing except internally in way of welds made by processes other than automatic. Equivalent proposals for testing will be considered.

7.3.1 Selected ballast tanks are to be hydraulically tested by filling with water to a depth equal to the maximum operational differential head taken from the hydrostatic curves. Three tanks are to be tested, one port, one starboard, and one middle tank, each at a different point along the length of the dock.

7.3.2 Oil tanks, fresh water tanks and cofferdams are to be separately tested by filling with water to the test head.

7.3.3 When water testing on the building berth is undesirable, testing is to be carried out afloat. The testing afloat is to be so arranged that each tank can successively be examined while being subjected to the head of water. Care is to be taken that the arrangements adopted for testing tanks afloat do not impose undue longitudinal stress on the dock.

7.3.4 Where a preservative coating is to be applied to the internal structure of a tank, the water testing may take place after the application of internal and/or external coatings, provided that the structure is carefully examined to ensure that all welding and structural stiffening are completed prior to the application of the coating. The cause of any discolouration or disturbance of the coating is to be ascertained and any deficiencies repaired.

7.4.1 On the completion of the dock, sinkage trials are to be carried out in the presence of an LR Surveyor. Fresh water tanks and the dock’s fuel tanks are to be full, but ship-oil tanks are to be empty. The travelling cranes may be so positioned that the draughts forward and aft are equal. The density of the water is to be recorded:

1. Normal condition. All ballast water is to be emptied so far as possible, only rest-water remaining. The draughts forward and aft, port and starboard, are to be recorded. The readings on deflection meters are to be taken. The deflection of the dock along the top of keel blocks is to be measured. Adjustment of the meters is then to be made, if necessary, so that they record this built-in permanent deflection in the normal condition. The light displacement is to be evaluated from these readings, and to obtain the light displacement, as defined in Pt 2, Ch 1, 2.1 General 2.1.2 , the weight of any compensating ballast water is to be added.

2. Sagging condition. Equal amounts of water are to be admitted to corresponding tanks on either side of the middle of the length, the depths increasing until the greatest depth is in the tanks at the middle of the length. The sagging bending moment so produced is to equal that evaluated in Pt 2, Ch 1, 3.3 Ship weight curve 3.3.1 and Pt 2, Ch 1, 3.5 Bending moment 3.5.3 respectively. The deflection meter readings are to be recorded and, by allowing for the permanent deflection (see Pt 2, Ch 1, 7.4 Sinkage trials 7.4.1), the sagging deflection is obtained.

Alternative arrangements to those described in Pt 2, Ch 1, 7.4 Sinkage trials 7.4.1.(b) will be specially considered.

7.4.2 When estimating the quantities of ballast water for Pt 2, Ch 1, 7.4 Sinkage trials 7.4.1.(b), the permissible difference in height of ballast water in adjacent compartments is not to exceed the pressure head for the compartments as laid down in Pt 2, Ch 1, 5.3 Tank plating 5.3.1.