Analysis, Model & Full-Scale Testing
experience in motion simulation started with the development of
frequency and time domain motion simulations of surface effect
ships operating in waves in support of the U.S. Navy Surface Effect
Ship Program. Over its 30 year history, these capabilities have
been refined and extended in support of the company's developments
of ride control systems for monohulls, catamarans, SWATHs and
can provide an analysis of a vessel's motion and assess the requirement
for the stabilization of pitch, heave, roll, and yaw motions by
means of trim tabs, interceptors, fins, T-foils, rudders or any
similar control device. The programs predict the statistical properties
of a vessel's motions with and without active ride control while
the vessel is running at any heading relative to a unidirectional
NAIAD simulation program first models the bare hull and simulates
the design's uncontrolled state. The predicted uncontrolled motions
can be compared to model test results to validate the simulation
program. At this time adjustments to the mathematical model are
made, if necessary. Next, using the active roll, pitch and yaw
control devices driven by an NAIAD controller, the motions are
predicted for the same sea conditions.
technical memorandum summarizing the results of the simulations
and discussing any design recommendation for improving seakeeping
or directional control problems is provided to the customer. The
results can be presented in graphical presentation for the standard
deviation of heave, pitch, roll, sway and yaw motions, as well
as vertical and lateral accelerations at customer selected locations.
The vertical and lateral acceleration results may be used to calculate
the Motion Sickness Incidence (MSI) and Motion Induced Interruption
(MII). In addition, Response Amplitude Operators (RAO) of the
vessel motions can be presented.
of the control surface resistance and power requirements are also
available. If ride control is deemed necessary, a technical specification
and quotation of the recommended system is provided.
simulation programs have been validated against both model and
full-scale test data both with and without active ride control
for a variety of hull forms.
2010 Naiad Maritime Group, Inc.