Section 7 Superstructures, deckhouses, bulwarks, sponsons and appendages

7.1.1 Superstructures, deckhouses, forecastles and bulwarks are to be constructed in accordance with the scantlings indicated in Vol 1, Pt 6, Ch 3, 11 Superstructures, deckhouses and bulwarks

7.1.2 For requirements relating to companionways, doors, accesses and skylights, see Vol 1, Pt 3, Ch 4 Closing Arrangements and Outfit

7.1.3 Requirements for machinery casings are given in Vol 1, Pt 3, Ch 2, 6.7 Machinery casings

7.1.4 For closing arrangements and outfit the requirements are given in Vol 1, Pt 3, Ch 4 Closing Arrangements and Outfit.

7.2.1 The term ‘house’ is used to include both superstructures and deckhouses.

7.2.2 The lowest, or first tier of a house, is normally that which is directly situated on the deck to which D, is measured. The second tier is the next tier above the lowest tier and so on.

7.3.1 The plating and supporting structure are to be suitably reinforced in way of localised areas of high stress such as corners of openings, cranes, masts, equipment, fittings and other heavy or vibrating loads.

7.3.2 Structures subject to concentrated loads are to be suitably reinforced. Where a concentration of loading on one side of a stiffener may occur, such as pillars out of line, the stiffener is to be adequately stiffened against torsion.

7.3.3 Primary stiffening members are to be continuous and substantially bracketed at their end connections to maintain continuity of structural strength.

7.3.4 Secondary stiffening members are to be effectively continuous and bracketed at their end connections as appropriate.

7.3.5 Transverse rigidity is to be maintained throughout the length of the house by means of web frames, bulkheads or partial bulkheads. Particular care is to be paid when an upper tier is wider than its supporting tier and when significant loads are carried on the house top.

7.3.6 Web frames or partial bulkheads are to be fitted in line with bulkheads or deep primary stiffeners below.

7.3.7 Special attention is to be given to the connection of the erection to the deck in order to provide an adequate load distribution and avoid stress concentrations. The house stiffening is to align with main hull stiffening wherever possible.

7.3.8 Where aluminium erections are arranged above a steel hull, details of the arrangements in way of the bimetallic connections are to be submitted.

7.3.9 Adequate support under the ends of houses is to be provided in the form of webs, pillars and diaphragms or bulkheads in conjunction with reinforced deck beams. At the corners of houses and in way of supporting structures attention is to be given to the connection to the decks and inserts or equivalent arrangements should generally be fitted.

7.4.1 All openings are to be substantially framed and have well rounded corners. Arrangements are to be made to minimise the effect of discontinuities in houses. Continuous coamings or girders are to be fitted below and above doors and similar openings. House tops are to be strengthened in way of davits and cranes.

7.4.2 Particular care is to be paid to the effectiveness of end bulkheads and the upper deck stiffening in way when large openings are fitted.

7.4.3 Special care is to be taken to minimise the size and number of openings in the sides or longitudinal bulkheads of houses which end within 0,25L _R to 0,75L _R. Account is to be taken of the high vertical shear loading which can occur in these areas.

7.4.4 Windows, ventilators and other superstructure openings are to be suitably framed and mullions will in general be required.

7.5.1 For ships where L _R exceeds 40 m or for designs where the superstructure is designed to absorb global loads the effectiveness of superstructures to carry these loads is to be determined. The effectiveness may be assessed in accordance with Vol 1, Pt 6, Ch 4, 2.5 Superstructures global strength

7.5.2 When large openings or a large number of smaller openings are cut in the superstructure sides, reducing the capability to transmit shear force between decks, an assessment of structural efficiency may be required. The scantlings of the side structure in way of these areas may also be required to be increased.

7.6.1 Primary structure supporting sponsons is to be effectively integrated into the main hull structure. This is to be achieved by extending the primary framing system or by suitable scarfing the sponson primary structure over at least five frame spaces.

7.6.2 The scantlings of sponson structure are to be as required by the relevant parts of Vol 1, Pt 6 Hull Construction in Steel, for decks or side shell. Decks used for aircraft operations or wheeled vehicles are to comply with Vol 1, Pt 4 Military Design and Special Features and Vol 1, Pt 6 Hull Construction in Steel respectively.

7.6.3 Where sponsons are located outside of 0,4L _R amidships and extend outside of the waterline breadth, B _WL, of the ship the effects of wave impacts are to be considered. The loads are to be derived in accordance with the bow flare slamming requirements in Vol 1, Pt 5, Ch 3, 3 Loads on shell envelope

7.6.4 The strength and arrangement of large bilge keels, stabilisers and other protrusions that may impinge on icebergs or flows are to be specially considered. In some cases the speed for operation in ice may be restricted.

7.7.1 Ships or structural arrangements which are of unusual design, form or proportions will be individually considered.