Floating Cranes. Technical documentation for the crane, including the
rotate bearing and its lower structural support, must be as described above. The
barge design, including the tub, must be reviewed and approved by the American
Bureau of Shipping (ABS). The floating crane contractor is required to make
arrangements with ABS for that purpose and provide the required technical
documentation. ABS review would consider the presence and effect of the crane in
the specified configurations.
ABS maintains authorized inspectors in the major U.S. ship building areas
and many foreign locations. These ABS inspectors provide
on-site surveillance and enforce the prescribed quality standards during the
construction of the vessels.
Other technical data that requires ABS review and approval includes the
trim and stability booklet, steel certificates, welding procedures, list of ABS
qualified welders and their certificates, and weld inspection and testing
documentation. Following review and approval of barge design, the contractor must
obtain from ABS a class certificate confirming that the barge was manufactured and
classed as a Maltese Cross A1 barge, International load Line certificate, and a
Fitness To Proceed Under Tow certificate (confirming approval of the towing plan).
Commercial Cranes. Standard commercial cranes and line hauling
mechanisms should be accepted with the standard documentation, in the form of
operational and maintenance manuals, customarily provided with the equipment.
Mobile and pedestal cranes warrant further elaboration. See paragraph 7.7, below.
Mobile Cranes. In the case of mobile cranes, the critical documentation
is the load charts, which establish the operating envelope for the crane in its
various configurations. The lifting capacities (load-radius combinations) are
governed by the stability and strength limits of the crane, which is the product
of a such key inputs as the boom length (and weight), reeving, rotate position,
and site conditions. It is important to note that the weight of the load block
(and on some models or configurations the wire rope) is considered part of the
Pedestal Cranes. Pedestal cranes should be procured from manufacturers
authorized by American Petroleum Institute to use the API monogram, which is a
registered trademark, and attests that the design and quality standards of API
have been met. Additional documentation required for these cranes is in the form
of load ratings. These cranes are variably rated for static and dynamic
conditions. Static ratings apply when there is no relative motion between the
crane and the load to be lifted; dynamic ratings apply when there is specific
relative motion between them. As with the mobile crane ratings, the load block is
considered part of the load.
Computer Analyses. Computer analyses are preferable to hand
calculations, especially for the design and evaluation of complex structural
assemblies. NCC policy is to accept computer-generated analyses provided that the
program is proven and generally recognized by the industry, and that the
presentation is properly tailored and its application is fully explained. As
minimum requirements for acceptability, the computer analyses must:
Provide program title (and version), concise description,
methodology, and assumptions.