Section 3 Lifting

3.1.1 The strength of shipboard fittings used to lift a linkspan pontoon in and out of water and their supporting hull structures are to comply with the requirements of this Section.

3.2.1 Padeyes and lifting lugs are to be located on stiffeners and/or girders which are part of the deck construction so as to facilitate efficient distribution of the lifting load. Other arrangements are acceptable, provided that the strength is confirmed adequate for the intended service.

3.3.1 The provision of padeyes is to be such that a uniform lift is achieved with no off-centre loading of the lifting appliance occurring.

3.3.2 The design of padeyes is to be in accordance with a recognised National or International Standard.

3.3.3 The padeye can be manufactured from one single plate, have a cheek plate fillet welded on each side of the plate or have a boss which is fillet welded through the plate, see Figure 10.3.1 Acceptable padeye design. Padeyes where the boss is only partly welded to the plate are not permitted.

Figure 10.3.1 Acceptable padeye design

3.3.4 All padeyes and lifting lugs are to be marked with their specific SWL. The locations and SWL of the padeyes and lifting lugs are to be recorded on the towing and lifting arrangement plan.

3.3.5 All padeyes and lifting lugs are to be tested to 1,5 times the SWL, as a vertical load only.

3.4.1 The net scantlings of supporting hull structures are to be assessed in accordance with Pt 3, Ch 10, 2.5 Strength of supporting hull structures where the design load is to be taken as the SWL of the padeye and the acceptance criteria are given in Table 10.3.1 Allowable stress within the supporting structure of padeyes. The reinforced members beneath the padeye are to be effectively arranged for any variation of direction (horizontally and vertically) of the lifting forces acting upon the padeye. Corrosion additions and wear down allowance are to be added to the net scantlings as defined in Pt 3, Ch 10, 2.6 Corrosion addition.

Table 10.3.1 Allowable stress within the supporting structure of padeyes

	Normal stress, in N/mm2	Shear stress, in N/mm2
Allowable stress
where σo = specified minimum yield strength of the material in N/mm2 Note Normal stress is defined as the sum of bending and axial stresses. No stress concentration factors are accounted for and as such may need to be considered separately.

3.5.1 The global strength of the pontoon (longitudinal and transverse) during lifting operations is to be assessed taking into account the hoisting speed of the lifting appliance, the stiffness of the wires, the residual weights, liquids, etc. on the pontoon and the distribution of the padeyes.