WEIGHTS & STABILITY

Gibbs & Cox, Inc. has an extensive database of weight data applicable to all phases of design accumulated throughout the 75 year history of the company. Preliminary weight and stability assessments are conducted using two ship synthesis software packages. The G&C developed ShipOPT and the US Navy's ASSET program, each of which utilize an extensive set of algorithms and user defined data to produce a high level assessment of ship stability, and a preliminary weight breakdown.

For more rigorous hydrostatic stability evaluations, we use General HydroStatics (GHS), developed by Creative Systems. GHS is able to model and evaluate all intact and damaged loading conditions. Compartment and tank weights and dynamic free surface moments are calculated within GHS using a user-defined compartmentation file. One of the most powerful features of GHS is the program's ability to evaluate given loading conditions against user defined stability criteria. This feature makes rapid assessment of alternate configurations and loading scenarios possible, which ultimately leads to an optimized design. GHS is also able to calculate and model heeling moments due to beam winds based on the user defined superstructure and hull geometry. Rapid development of maximum KG curves is possible using the programs "MAXVCG" command. G&C has developed several sub-routines which run inside the main GHS program which cater to specific client requirements.

Gibbs & Cox, Inc. also has extensive experience in evaluating the dynamic stability of a candidate vessel. We use the CRNav program FREDYN to model the 6 degree-of- freedom motions of a ship through a range of environmental conditions. This capability has been developed in parallel with the US Navy's newly issued "Stability for Mono hull Surface Combatants". Using these tools and the emerging methodologies for quantifying the dynamic stability of a vessel, Gibbs & Cox, Inc. is able to calculate the probability of dynamic instability of a Navy Surface Combatant during her service life.