Section 4 Bottom Surveys – In Dry-Dock and In-Water Surveys - Hull and machinery requirements

4.1.1 At Bottom Surveys, the Surveyor is to examine the outside of the craft’s bottom and associated appendages, including rudders, propellers and thrusters.

4.2.1 Where a craft 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 outside of the hull, rudder(s) and underwater fittings. The outside surface of the hull is to be cleaned as may be required by the Surveyor.

4.2.2 Attention is to be given to parts of the external hull structure particularly liable to structural deterioration from causes such as high stresses, chafing and lying on the ground, and to areas of structural discontinuity.

4.2.3 The following parts of the external hull structure are to be specially examined:

1. For steel hulls attention is to be given to parts of the structure particularly liable to excessive corrosion and to any undue unfairness of the plating of the bottom. The coating system is to be examined and made good as necessary.

2. For aluminium alloy hulls attention is to be given to areas adjacent to any bimetallic connections at skin fittings, etc.

3. For composite hulls the gelcoat or other protective finish is to be examined for surface cracking, blistering or other damage which may impair the efficiency of the protection to the underlying laminate.

4.2.4 Where required by the Rules, the satisfactory condition of the cathodic protection is to be confirmed.

4.2.5 Visible parts of the rudder, rudder pintles, rudder stocks and couplings and stern frame are to be examined. The pintles are to be examined either by removal of the inspection plates, or if considered necessary by the Surveyor, the rudder is to be lifted to enable examination. The clearances in the rudder bearings and pintles are to be measured. The securing of rudder couplings and/or pintle fastenings is to be confirmed.

4.2.6 The sea chests, sea connections, scuppers and sanitary discharges, their attachments to the hull and the gratings at the sea inlets are to be examined.

4.2.7 Visible parts of the propeller(s) and sternbush(es), are to be examined. The clearance in the sternbush and the efficiency of the oil gland, if fitted, are to be ascertained and recorded. For controllable pitch propellers, the Surveyor is to be satisfied with the fastenings and tightness of hub and blade sealing.

4.2.8 The clearance of any shaft bracket bearings is to be ascertained.

4.2.9 The inboard shaft seals or glands are to be examined. Where flexible stern glands are fitted, the satisfactory condition of the rubber hose and securing clips is to be confirmed.

4.2.10 Special attention is to be given to the hull in way of underwater fittings such as transverse thrusters, stabilisers, etc.

4.2.11 Where applicable, attention is to be given to the connection and/or intersection of the cross-deck structure to the hulls of multi hull craft.

4.2.12 Visible parts of side thrusters are to be examined. Other propulsion systems which also have manoeuvring characteristics (such as directional propellers, vertical axis propellers, water jet units) are to be examined externally with focus on the condition of gear housing, propeller blades, bolt locking and other fastening arrangements. Sealing arrangements of propeller blades, propeller shaft and steering column are to be verified.

4.2.13 Where water jet units are fitted, the impeller, hull ducting, grating, nozzle steering and reversing arrangements are to be examined as far as is practicable.

4.2.14 Where transom mounted propulsion units are fitted, the steering arrangements and any flexible transom seals are to be examined.

4.2.15 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 – General 5.3.7, and Table 3.5.1 Survey preparation.

4.2.16 For SES craft any flexible skirts together with their attachment are to be examined.

4.2.17 For hydrofoil or foil assisted craft the attachment of foils is to be examined.

4.2.18 To maintain an *IWS notation, at completion of each dry-docking the condition of the high resistance paint is to be confirmed, and, as applicable, satisfactory access arrangements to take the sternbush clearance and rudder pintle/bearing clearances are to be verified.

4.2.19 Where the anti-fouling system is changed completely, or partial repair is carried out affecting 25 per cent or more of the system, the coating specification and anti-fouling system is to be examined by the Surveyor in accordance with the AFS - International Convention on the Control of Harmful Anti-Fouling Systems on Ships, 2001 and Ch 15 Corrosion Prevention of the Rules for the Manufacture, Testing and Certification of Materials, July 2022.

4.3.1 The Committee will accept an In-Water Survey at alternate Bottom Surveys on craft where an *IWS notation is assigned, see Pt 1, Ch 2, 3.8 Other hull notations 3.8.2.

4.3.2 The Committee may accept an In-water Survey at alternate Bottom Surveys on craft where suitable protection is applied to the underwater portion of the hull. If requested, an *IWS class notation may be assigned on satisfactory completion of the survey, provided that the applicable requirements of the Rules are complied with, see also Pt 1, Ch 2, 3.8 Other hull notations 3.8.2.

4.3.3 In-Water Survey is to provide the information normally obtained from the Bottom Survey in dry-dock. However, for oil lubricated sternbush arrangements, the clearance in the sternbush is not required to be ascertained subject to the Surveyor confirming satisfactory operating history and condition data records (lubricating oil analysis, bearing temperature, lubricating oil consumption) and verifying satisfactory operation of the screwshaft.

4.3.4 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.

4.3.5 The In-Water Survey is to be carried out at agreed geographical locations under the surveillance of a Surveyor to LR, with the craft in sheltered waters; the in-water visibility and the cleanliness of the hull below the waterline is to be clear enough to permit a meaningful examination which allows the Surveyor and diver to determine the condition of the plating, appendages and the welding. The Surveyor is to be satisfied with the methods of orientation of the divers on the plating, which should make use where necessary of permanent markings on the plating at selected points.

4.3.6 The In-Water Survey is to be carried out by a qualified diver employed by a firm approved by LR. In addition, for certain aspects of the In-Water Survey, consideration may be given to the use of a Remotely Operated Vehicle (ROV) operated by the LR approved firm.

4.3.7 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.

4.3.8 If the In-Water Survey reveals damage or deterioration that requires early attention, the Surveyor may require that the craft be dry-docked in order that a fuller survey can be undertaken and the necessary work carried out.