0027/nd guidelines for Marine Lifting and Lowering Operations

18.6 
VESSEL MOTIONS AND OPERATIONAL DETAILS 
18.6.1 
Crane vessel motions should be monitored in the period prior to the lift to confirm that the dynamic 
behaviour is acceptable taking into account:

The weight and size of the lifted object,

The clearances for lifting off the transport barge,

The hoisting speed,

The clearances for installation, and

The installation tolerances. 
18.6.2 
Transport barge motions should be similarly monitored prior to the start of the lift. The change in 
attitude of the transport barge when the weight is removed should be taken into account. 
18.6.3 
When setting down on a floating structure, the set down procedure shall show how the lifted load will 
affect the draft and trim of the floating structure. The allowable range of lowering speeds shall be 
determined to avoid snatch loads, lift off or excessive motions of the floating structure. 
18.6.4 
For vessel to vessel lifts, the relative motion between crane hook and object should be carefully 
evaluated before the commencement of the lift. Relative motions of more than 2.0 metres are not 
recommended. 
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GUIDELINES
 
FOR
 
MARINE
 
LIFTING
 
&
 
LOWERING
 
OPERATIONS 
0027/ND Rev 11 
 
Page 65 of 84 
18.6.5 
Ballasting of the transport barge prior to or during lifting in order to obtain simultaneous lift off at all 
support points should be considered. 
18.6.6 
When lifting from another vessel/barge or from shore by crane vessels, possible restraint loads 
between crane vessel and lifted object should be relieved by slackening mooring lines as much as 
possible and restricted use of thrusters.