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Scientific Software for Naval Architectural Analyses

The tools that you need to do your job as a naval architect or a marine designer. The tools that work and not hastily put into market for the next upgrade. Developed, tested and used for over 15 years in various marine design applications encompassing commercial and military programs for ships, yachts, work boats, catamarans, SES, and SWATH, the products have been the workhorse for all projects. Their thoroughness compared to others in the market is unparalleled. These are the tools you need to meet regulatory approvals ( IMO, Classification Societies, Coast Guard ) for your vessel design.

MARITECH Corporation software suite consists of HYDRO (Hydrostatics characteristics and Curves of Form), ISTAB (Intact stability analysis), and DAMSTAB (Damaged Stability Analysis) programs. These programs constitute the most fundamental tools a vessel designer can have to validate a design. They are used to develop naval architectural characteristics for vessel design encompassing conventional mono hulls, catamarans, SES and SWATH hull forms. The modules can be purchased individually or as a suite. Free technical support is provided for 90 days to all registered owners. A brief description of each module that make up the suite (HYDRO + ISTAB + DAMSTAB) is described below.

Hull Form Data

The analytical process starts with the hull lines which requires digitization in the form of X, Y, Z coordinates for relevant hull stations and/or frames. The X, Y, ,Z coordinates of the hull defining the contour may be obtained either directly from a CAD drawing or can be manually prepared from a hard copy drawing of Body Stations by direct scaling. The hull offset data is prepared in ASCII format for each hull station in transverse section with station X value from a reference station. The transverse contour for each station/frame is described by points with height (Z) and half-breadth (Y), starting from the highest point of the deck, describing it in a counter-clockwise direction and back to the starting point to the deck. The transverse contour is required to be a closed section. If the contour is symmetrical about the centerline, it needs to be described for one side only by appropriate code in the program. For any hull discontinuities, they are modeled by points description (Z, Y). A number of station/frame data is prepared to define the hull from forward to aft (stem to stern). Depending on the hull's longitudinal discontinuities, additional station/frame data is prepared as required to simulate the appropriate discontinuity at any given location. Once all station data is compiled in the form of X, Y, ,Z format, the program GEOCHECK (included in the program suite) is used to validate the hull model. It generates a model in dxf format which can be imported as a drawing file into any popular CAD program that user has a setup. The model is viewed, revised for error if any and the acceptable model is saved for use as the common database for the naval architectural analyses. All modules of the naval architecture suite read the same digital hull model database for consistency in analysis and results.

New tool for Body Stations digitizing

MARITECH has added a new AutoLisp program to significantly reduce time for digitizing the hull form body stations directly from the screen display and save a formatted ASCII file to a given path and filename. The resulting output is exactly compatible for all applications discussed here. This enhancement is for users who use AutoCAD (r14 and up) from Autodesk, Inc. The DIGITIZER (software) is a lifesaver for creation of the digital model.

Example of hull body model described in X, Y, ,Z input or digitized from CAD

Coordinate system for model description

Hull design in CAD environment

Checkplot of digitized hull body in GEOCHECK

HYDRO: Hydrostatic Characteristics and Curves of Form

(Curves of Form)
HYDRO generates hydrostatic characteristics of ships and boats for a range of waterlines in zero trim condition. It requires the digital model of the hull form as prepared earlier and a simple input data describing principal dimensions, number of waterlines, and hull form code to generate a complete set hydrostatic characteristics for each waterline. In addition to the output, a set of Bonjean data (section area) for each hull station/frames is generated. A comprehensive user's manual shows how to run the program which includes sample input and output. The tabular results consist of various displacement values, centers of buoyancy, center of flotation, metacenter values for stability assessment and other hydrostatic properties relevant to the specific design.

Click here to see a typical output from HYDRO

ISTAB: Intact Stability Characteristics
ISTAB generates transverse stability characteristics of a vessel in intact (undamaged) condition for any given displacement and centers of gravity. The program analytic is designed to balance the flotation in four constrained parameters (displacement, and three centers of gravity: longitudinal, vertical, and transverse, to derive the equilibrium condition for the specific loading condition. Then it goes on to derive the righting arm values (GZ) for a range of heel angles (PHI).

The most powerful capability of ISTAB is its ability to process openings in the hull or on deck where down-flooding may occur under beam wind, combined with rolling. During computation of righting arms (GZ) for each heel angle (PHI), the program checks if any down-flooding that may occur at each inclination through any of all the defined openings . If it does, then these heel angles are identified in the tabular output to inform the investigator the range of acceptable GZ vs. PHI for computation of righting energy in the system. No other similar programs are known in the market to have such capability.

The derived information can be used to prepare stability compliance check as required by regulatory authorities or IMO stability requirements.

Click here to see a typical output from ISTAB.

DAMSTAB: Damaged Stability Analysis
DAMSTAB is the most comprehensive analytical tool available to evaluate survivability characteristics of any vessel under various conditions of hull damage. You need an analytical tool like this to meet the most demanding requirements of regulatory authorities (IMO, MCA, Coast Guard, Classification Societies). The flooding compartments are described by compartment geometry information, either directly created from hull offset or specifically described by the investigator. The compartment description may include free-flooding spaces such as air ducts, moon pools and other areas within the hull considered to be potential floodable spaces. This is a unique capability of DAMSTAB where hydrostatic characteristics are integrally calculated as opposed to externally defined appendages. All computations are done under the constraints of constant displacement and trim. The output results are tabulated in a manner which can be easily integrated in the main body of the report for design documentation.
Similar to ISTAB, DAMSTAB has the capability to process openings in the hull or on deck. During computation of righting arms (GZ) for each heel angle (PHI), the program checks if any down-flooding is likely for each inclination (PHI) through any of all the defined openings . If it does, then these heel angles are identified in the tabular output to inform the investigator the range of acceptable GZ vs. PHI for computation of residual energy in the system (area under PHI-GZ curve). No other similar programs in the market are known to have such capability.

Damaged stability analysis is mandatory to meet IMO (International Maritime Organization) codes for new or modified vessel design.

The input to DAMSTAB is the same digital hull model as used by HYDRO, and/or ISTAB. This is supplemented by user defined initial ship condition and flooding compartments description. The input stream is simple and straightforward for a complex analysis like DAMSTAB.

Click hereto see a typical output from DAMSTAB.

STABTST: Stability Test Analysis (Inclining Experiment)

STABTST is designed specifically to prepare a set of hydrostatic properties for the stability test of a vessel. The exact hydrostatic characteristics are computed from draft readings along the length of the vessel, taken during the test. As many as ten sets of draft readings may be used to derive hydrostatic characteristics. This is especially necessary for long slender hulls because of hull structural deflection. The calculated transverse metacenter (KMt) from STABTST is then used in conjunction with derived GMt from pendulum readings to derive vertical center of gravity (VCG) of the vessel at the time of the test. This conforms to the requirements of ASTM F1321 as mandated by the U.S. Coast Guard (NAVIC 17-91).

Click hereto see a typical output from STABTST

Minimum System Requirements

Personal computer with Intel Pentium CPU
Windows operating platform
32 MB RAM
4 MB free hard disk space
CD ROM

Software prices (US$, excluding S/H):

Software suite is available in both US customery unit or SI unit.

NAVTECH Suite of Software	US$ 2395.00
Hydrostatic module: HYDRO	Included
Intact Stability module: ISTAB	Included
Damaged Stability module: DAMSTAB	Included
Stability Test Analysis module: STABTST	(Optional: $695)
On-Screen Hull form DIGITIZER	Included

For ordering information, please go to Home/Contact or call [USA] (619)283-3853
We accept certified bank check or money order (domestic or international)

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