Section 4 Docking Surveys and In-water Surveys – Hull and machinery requirements

4.1.1 At Docking Surveys or In-water Surveys in lieu of Docking Surveys, the Surveyor is to examine the unit and machinery, so far as necessary and practicable, in order to be satisfied as to the general condition, see also Pt 1, Ch 2, 3.5 Existing installations – Periodical Surveys.

4.2.1 Where a unit is in dry dock or on a slipway, it is to be placed on blocks of sufficient height, and proper staging is to be erected as may be necessary, for the examination of the shell, including bottom and bow plating, keel, sponsons and appendages, stern, sternframe and rudder. The rudder is to be lifted for examination of the pintles if considered necessary by the Surveyor.

4.2.2 For self-elevating units, the leg footings and those parts of the leg and hull that are normally under water are to be examined. The connections between leg chords and the footings or mats are to be inspected and subjected to NDE.

4.2.3 For self-elevating units, at each Docking Survey or In-Water Survey coinciding with Special Survey, the Surveyor is to be satisfied with the internal condition of the leg footings or mats. Leg connections to leg pads are to be nondestructively tested. Non destructive testing may be required of areas considered to be critical or found to be suspect by the Surveyor. Non-metallic expansion pieces in the main seawater cooling and circulating systems are to be examined both externally and internally.

4.2.4 For column-stabilised units, external surfaces of the upper hull or platform, footings, pontoons or lower hulls, underwater areas of columns, bracing and their connections, sea chests, and propulsion units as applicable, are to be selectively cleaned and examined to the satisfaction of the attending Surveyor. Non-destructive testing may be required of areas considered to be critical or found to be suspect by the Surveyor.

4.2.5 The shell plating is to be examined for excessive corrosion, deterioration due to chafing or contact with the ground and for undue unfairness or buckling. Special attention is to be given to the connections between the bilge strakes and bilge keels.

4.2.6 The external cathodic protection system and coatings are to be examined.

4.2.7 The clearances in the rudder bearings are to be measured. Where applicable, pressure testing of the rudder may be required if deemed necessary by the Surveyor.

4.2.8 The sea connections and overboard discharge valves and cocks and their attachments to the hull are to be examined.

4.2.9 Thrusters, propeller, sternbush and sea connection fastenings and the gratings at the sea inlets are to be examined.

4.2.10 The clearance in the sternbush or the efficiency of the oil glands is to be ascertained.

4.2.11 When chain cables are ranged, the anchors and cables are to be examined by the Surveyor, see also Pt 1, Ch 3, 5.3 Examination and testing. For units having a positional mooring notation in accordance with Pt 3, Ch 10 Positional Mooring Systems, the positional mooring systems and associated equipment are also to be examined.

4.2.12 For electrical equipment survey requirements of units five years old and over, see Pt 1, Ch 3, 9.2 Complete Surveys.

4.3.1 The Classification Committee will accept an In-Water Survey in lieu of the intermediate docking survey between Special Surveys on units other than those where an OIWS notation is assigned, see Pt 1, Ch 2, 2.4 Class notations (hull/structure). where suitable protection is applied to the underwater portion of the hull and provided the information in paragraphs Pt 1, Ch 3, 4.3 In-water surveys. and Pt 1, Ch 3, 4.3 In-water surveys are complied with.

4.3.2 Special arrangements must be incorporated into the unit's design or otherwise provided to allow adequate survey of thrusters, stern bearings, rudder bearings, sea suctions and valves, etc., see Pt 3, Ch 1, 2.1 General.

4.3.3 Special consideration shall be given to ascertaining rudder bearing clearances and sternbush clearances, based on a review of the operating history, onboard testing and stern bearing oil analysis. These considerations are to be included in the proposals, see 4.3.5.

4.3.4 The In-water Survey is to provide the information normally obtained from the Docking Survey, so far as practicable.

4.3.5 Proposals for In-water Surveys are to be submitted in advance of the survey being required so that satisfactory arrangements can be agreed with LR.

4.3.6 A planned procedure for the routine inspection of the underwater areas is to be agreed between the Owners and LR. A procedure document is to be placed on board the unit and made available to the Surveyor. Where survey experience indicates that modifications are required to the inspection procedures, the procedure document is to be modified to the satisfaction of LR.

4.3.7 The In-water Survey is to be carried out at an agreed geographical location, with the Surveyor to LR satisfied that the unit at a suitable draught and the conditions satisfactory for diver or ROV inspection. The in-water visibility is to be good and the hull below the waterline is to be clean. The Surveyor is to be satisfied that the method of pictorial presentation is satisfactory. There is to be good two-way communication between the Surveyor and the diver/ROV operator. The Survey is to be witnessed by the Surveyor. This requires the Surveyor to be on board while the Survey is carried out, to the extent necessary to control the process. The Surveyor may extend the scope of Survey if deemed necessary.

4.3.8 In general, the In-water Survey is to be carried out by an approved diving company with suitably qualified divers. Alternatively, the In-water Survey may be carried out using a suitable ROV, subject to agreement with the attending LR Surveyor. The ROV should be fitted with suitable cameras, transmission and recording facilities.

4.3.9 The efficient condition of the cathodic protection system and the high resistance paint is to be confirmed at each In-water Survey to the satisfaction of the Surveyors, in order that the OIWS notation can be maintained.

4.3.10 If the In-water Survey reveals damage or deterioration that requires early attention, the Surveyor may require that the unit be dry-docked, in order that a more detailed survey can be undertaken and the necessary work carried out.

4.3.11 Diver/ROV-assisted surveys are not acceptable for the periodic survey inspections of primary bracing members, or intersections of bracings with columns or pontoons, or column to pontoon intersections on column-stabilised units, except in exceptional circumstances when specially agreed with the Classification Committee and the procedures have been approved, see also Pt 1, Ch 3, 2.2 Structure and equipment.

4.3.12 Turret and bearings below water level, underwater parts of mooring towers and/or articulated towers (where applicable), chain stoppers, chain cables and mooring lines/chains are to be examined as far as practicable during In-water Surveys. On tension-leg units, tethers and their upper and lower connections are to be examined.

4.3.13 For electrical equipment survey requirements of units five years old and over, seePt 1, Ch 3, 9.2 Complete Surveys.

4.3.14 Some National Administrations may have requirements additional to those of 4.3.1 to 4.3.13.

4.3.15 For self-elevating units, the requirements of Pt 1, Ch 3, 4.2 Docking surveys are to be undertaken as far as practicable with due consideration to the operation and location of the unit.