applies an evolved version of strip theory in a particularly efficient
way to calculate the ship motions response amplitude operators in
6 degrees of freedom. ShipmoPC has been validated for Froude numbers
as high as 0.42 . Other features include keel immersion and slamming,
and deck wetness probability prediction.
Several wave types and sea spectra are supported, with user-defined
height, length and direction. Industry standard interfaces allow
ShipmoPC to be used in conjunction with any hull design software.
Its intuitive user interface
and comprehensive supporting documentation make ShipmoPC easy to use
even by ? ShipmoPC Seakeeping Prediction Software
ShipmoPC is a derivation of the SHIPMO seakeeping predictions code
developed by the Canadian Defence Research Establishment Atlantic
(DREA). Specifically, ShipmoPC incorporates the core computer code
from the SHIPMO4 version.
ShipmoPC is a strip-theory based frequency domain seakeeping code capable
of computing the six degree-of-freedom motions of a monohull with
forward speeds in regular as well as irregular seas of arbitrary
headings. Response Amplitude Operators (RAO's) for the longitudinal
(heave, pitch and roll) and the lateral (sway, roll and yaw) motions
are derived for the complete range of frequencies using the hull
geometry input for the specified speeds and headings. Also included
are load components - shear forces, bending moments and torsion.
The ship dynamics model of ShipmoPC is capable of accounting for the
hydrodynamic effects from rudders, bilge keels and other appendages
as well as tank roll stabilizers. Autopilot routines are built in
that allow rudder roll stabilization to be modelled.
most significant development of the new version is the addition
of a load calculation module that has been developed and extensively
validated at DREA through sea trials and model tests. The predicted
load components involve vertical, lateral and torsional shear forces
and bending moments.
in an irregular seaway may be calculated either by specifying a
theoretical spectrum or by a set of measured spectral ordinates
input by the user. The theoretical spectral formulations built into
the code are quadratic regression spectrum and Bretschneider spectrum.
Both unidirectional and short-crested seas can be specified, the
latter being represented by cosine-squared spreading. Computed results
such as RAOs (amplitudes and phases) and the significant (single
amplitude) motions in all the six modes are generated. For the specified
locations on the hull, computed output includes parameters such
as accelerations, probability and frequency of incidence of deck
wetness, keel emergence and slamming, as well as slam pressures
and forces. In addition, an index showing human tolerance to vertical
motions is also provided. The
program will produce habitability indices such as Motion-induced
ShipmoPC has been validated against a large number of ships ranging
from coastal defence vessels to cargo ships as well as barges, icebreakers
and naval ships. ShipmoPC, the commercial version of SHIPMO4, was
developed by Fleet Technology Limited for its software subsidiary,
Sable Maritime Limited.
In order to predict the motions accurately, it is necessary to ensure
that the hydrostatics parameters are correct. The hydrostatics may
therefore be run independently, allowing the user to assure correctness
before proceeding with the hydrodynamic computations.
ShipmoPC results are both tabular and graphical. The user will typically
select to view RAOs (six degrees of freedom) or RMS motions for
various ship speeds, headings and sea states.