Download ShipMo3D Version 3.0 User Manual for Computing Ship Motions in

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Introduction
ShipMo3D is an object-oriented library with associated applications for predicting
ship motions. This report describes applications for predicting ship motions in the
time and frequency domains. A companion report [1] is the user manual for creating
ship models required for computing ship motions. For each ShipMo3D application,
user input is read from an ASCII input file. Each application produces an ASCII
output file, and many applications also produce graphical output. The ShipMo3D
graphical user interface (GUI), ShipMo3D30.exe, can be used to interactively prepare
input data, launch applications, and view output results.
Several reports describe the theory behind ShipMo3D, and also give verification and
validation of ShipMo3D results. References 2 and 3 describe the prediction of hull hydrodynamic forces. The modelling of seaways is described in Reference 4. Reference 5
covers appendage and viscous forces, which are important for predicting lateral plane
motions. The extension of ShipMo3D to freely maneuvering ships is described in
Reference 6, with refinements to maneuvering forces given in Reference 7. ShipMo3D
Version 3.0 introduces modelling of U-tube tanks [8] and sloshing in tanks with free
surfaces [9]. Reference 10 gives validation results for Version 3.0 of ShipMo3D.
Section 2 of this report describes features that are new for Version 3 of ShipMo3D.
Section 3 gives an overview of predicting motions using ShipMo3D. Section 4 describes coordinate systems used for motions and ship geometry. Section 5 describes
the application SM3DBuildSeaway for building a model of a seaway. Time domain
motions in a seaway or in calm water can be computed using SM3DFreeMo, described in Section 6. Sections 7, 8, 9 and 10 describe the applications SM3DSeakeepRegular, SM3DSeakeepRandom, SM3DSeakeepSeaway, and SM3DSeakeepSeawayFromRaos which are used to predict motions in the frequency domain for
various types of sea conditions. The post-processing program SM3DTimeSeriesFromRaos is described in Section 11. Section 12 describes inputs for the rudder autopilot
and Section 13 describes various inputs for seakeeping predictions in random seas.
Final conclusions are given in Section 14. Annexes at the end of the report give input
file descriptions and sample input and output files for the ShipMo3D applications.
Detailed input formats and sampled files are given in Annexes A to G. For brevity,
some portions of sample output files have been removed from this document; however,
full sample output files are available for the software.
DRDC Atlantic TM 2011-308
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