Civil Engineering Reference
In-Depth Information
TABLE 5.4
Offshore Lifting Terminology
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Term
Definition
Contingency
An amount (in tons) to accommodate future changes in topside
functional requirements instigated by management or by unex-
pected production changes.
Crane vessel
The vessel, ship or barge on which lifting equipment is mounted.
It is considered to include a crane barge, crane ship, derrick
barge, floating shear-legs, heavy lift vessel and semi-submersible
crane vessel (SSCV).
Determinate lift
A lift where the slinging arrangement is such that the sling loads
are statically determinate and are not significantly affected by
minor differences in sling length or elasticity.
Dynamic amplifica-
tion factor
The factor by which the gross lift weight is multiplied, to account
for dynamic loads and impacts during the lifting operation.
Grommet
A grommet is comprised of a single length of unit rope laid 6
times over a core to form an endless loop.
Factored weight
The factored weight of any individual item is characterized by its
base weight multiplied by the product of all relevant allowances.
Gross weight
The calculated weight of the structure to be lifted, including
contingencies, or the weighed weight, including weighing
allowance.
Hook load
The hook load is the summation of the lift weight and the rigging
weight.
Indeterminate lift
Any lift where the sling loads are not statically determinate.
Lift point
The connection between the rigging and the structure to be lifted.
May include padear, padeye or trunnion.
Lift weight
The lift weight is the gross weight in addition to the allowance for
dynamic effects.
Load-out
The transfer of topside or jacket from land onto a barge by hori-
zontal movement or by lifting.
Load-out, lifted
A load-out performed by a crane.
Minimum required
breaking load
The minimum allowable value of breaking load for a particular
lifting operation.
Net weight
The calculated or weighed weight of a structure, with no con-
tingency or weighing allowance.
Padear
A lift point consisting of a central member, which may be tubular
or a flat plate form, with horizontal trunnions around which a
sling or grommet may be passed.
(Continued)
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