Clasification Society Rulefinder 2020 - Version 9.33 - Fix
Common Structural Rules - Common Structural Rules for Bulk Carriers and Oil Tankers, January 2019 - Part 1 General Hull Requirements - Chapter 11 Superstructure, Deckhouses and Hull Outfitting - Section 4 Supporting Structure for Deck Equipment and Fittings - 4 Cranes, Derricks, Lifting Masts and Life Saving Appliances

4 Cranes, Derricks, Lifting Masts and Life Saving Appliances

4.1 General

4.1.1 Supporting structure of life saving appliances and supporting structures of cranes, derricks and lifting masts with a Safe Working Load greater than 30 kN, or a maximum overturning moment to the supporting structure greater than 100 kNm, are to comply with these requirements.

4.1.2

These requirements apply to the connection to the deck and the supporting structure of cranes, derricks and lifting masts. Where the crane, derrick or lifting mast is to be certified by the Society, additional requirements may be applied by the Society.

4.1.3

These requirements do not cover the following items:
  1. Supports of lifting appliances for personnel or passengers, except foundation for life saving appliances.
  2. The structure of the lifting appliance pedestals or post above the area of the deck connection.
  3. Holding down bolts and their arrangement, which are considered part of the lifting appliance.

The term ‘lifting appliance’ is defined as a crane, derrick or lifting mast.

4.1.4 SWL Definition

The Safe Working Load (SWL) is defined as the maximum load which the lifting appliance is certified to lift at any specified outreach.

4.1.5 Self weight

The self weight is the calculated gross self weight of the lifting appliance, including the weight of any lifting gear.

4.1.6 Overturning moment

The overturning moment is the maximum bending moment, calculated at the connection of the lifting appliance to the ship structure, due to the lifting appliance operating at Safe Working Load, taking into account outreach and self weight.

4.1.7

The crane pedestal and derrick mast are as defined in Figure 3.

4.1.8

Deck plating and under deck structure is to provide adequate support for derrick masts and crane pedestals against the loads and maximum overturning moment. Where the deck is penetrated, the deck plating is to be suitably strengthened.

4.1.9

Structural continuity of the deck structure is to be maintained. Under deck members are to be provided to support the crane pedestal and to comply with:
  1. Where the pedestal is directly connected to the deck, without above deck brackets, adequate under deck structure directly in line with the crane pedestal is to be provided. Where the crane pedestal is attached to the deck without bracketing or where the crane pedestal is not continuous through the deck, welding to the deck of the crane pedestal and its under deck support structure is to be made by suitable full penetration welding. The design of the weld connection is to be adequate for the calculated stress in the welded connection, in accordance with [4.1.15].
  2. Where the pedestal is directly connected to the deck with brackets, under deck support structure is to be fitted to ensure a satisfactory transmission of the load, and to avoid structural hard spots. Above deck brackets may be fitted inside or outside of the pedestal and are to be aligned with deck girders and webs. The design is to avoid stress concentrations caused by an abrupt change of section. Brackets and other direct load carrying structure and under deck support structure are to be welded to the deck by suitable full penetration welding. The design of the connection is to be adequate for the calculated stress, in accordance with [4.1.15].

Figure 3 : Crane pedestal and derrick mast

4.1.10

Deck plating are to be of a material strength compatible with the crane pedestal. Where necessary, a thicker insert plate is to be fitted. In no case are doublers to be used where structures are subject to tension.

4.1.11

The supporting structure is to be dimensioned to ensure that for the load cases specified in [4.1.13] and [4.1.14], the stresses do not exceed those given in [4.1.15]. The capability of the supporting structure to resist buckling failure is to be assured.

4.1.12

These requirements are to be assessed based on gross scantlings.

4.1.13

For lifting appliances which are limited to use in harbour, design load is to be taken equal to 1.3 times SWL added to the lifting appliances self weight.

4.1.14

For life saving appliances, design load is to be taken as 2.2 times SWL.

4.1.15

The stresses induced in the supporting structure are not to exceed the following permissible values:
  • Normal stress, 0.67 ReH
  • Shear stress, 0.39 ReH
Parent topic: Section 4 Supporting Structure for Deck Equipment and Fittings
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