About the app
This product can be used by engineers and designers for rapidly generating rigging arrangements for 4-point lift design. There are two versions of the product: one with ‘no-tilt’ and other with ‘controlled-tilt’. Descriptions below:
|‘No-tilt’ and ‘No-tilt Plus’ Versions||Version with ‘Controlled-tilt’|
Work points and simple sling load estimates are calculated for “ideal” preliminary 4-Point, Single Hook lift arrangements where there is no Package “tilt” afterwards. It is aimed at fabrication yard engineers and knowledgeable designers who just need some guidance in layout of rigging systems and general sizing of rigging components. Estimates of the sling loads are made but detail strength design of padeyes and final selection of rigging components such as shackles and slings require further calculations. These latter calculations may be performed using App “Four point lift – DNV“. Design calculations for padeye design may also be performed using App “Pad-eye design app“. (Both of these latter Apps are available through “TheNavalArch.com” ).
No-tilt Plus Version
No-tilt version also has an advanced version called ‘No-tilt Plus’ which does everything which the no-tilt version does. In addition, input data for rigging arrangement “sub-models” for structural analysis programs SACS and StaadPro may be extracted to Windows text files that can be read by these analysis programs. Complimenting the sub-models,
|Work points are calculated for a 4-Point, Single Hook lift arrangements where Package “tilt” after lift-off is allowed. It is aimed at fabrication yard engineers and knowledgeable designers. Instead of working out an ideal hookpoint for zero tilt, the approach taken by this App is to constrain the location of the hookpoint to be over a central axis between a pair of corner lift points. This leads to one or more pairs of sling systems having the same length, where a sling system consists of a central rope plus end fittings such as shackles.|
The ideal starting point for applying this App is a “zero-tilt” rigging arrangement where estimates of sling loads have been made and rigging components sized on that basis. The arrangement resulting from use of this App will ideally involve simple adjustment of the hookpoint relative to the ideal case so that the forces in the rigging components will be approximately the same as those predicted for the “ideal” ie zero-tilt case.
Available options for both Apps are “with” and “without” spreader beam/bar. These are of interest to those dealing with packaged equipment intended to be lifted pre-service with a single crane.
These Apps can accommodate a wide range of Package weights, location of the four lift points, and location of the centre-of-gravity. Selected spot input and output checks are included to alert the user to inconsistencies in the data.
In addition to listed output data, a simple interface Excel data file is dumped to serve as input to companion App “GenerateAcadStarterRiggingModelV1.xlsm”
which guides the creation of a “starter” rigging arrangement model in Autocad 3D. This ensures that the key rigging work points are correctly located in 3D space at the beginning of the design process so that the engineers and designers involved are aligned right from the start. This AutoCAD 3D model can be further detailed by User’s designers.