NAVCAD
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Minimum hardware required: PI 133, (64 Mb for Win NT)
Operating system(s): Windows NT, 2000, XP
Most recent version date & number: October 2009 , 2009.5
Number of installations:

400+






 
  Description
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NavCad™ version 2009 includes many new features, such as:

      Interface update - A new design of main Resistance and Propulsion pages, including analysis parameter entry tables

      Task List - A user Task List to create and track project tasks.

      Hydroacoustic analysis - Estimate blade impulse and tip vortex pressures.

      Cavitation analysis - A new proprietary prediction method for propellers in the transcavitating mode was added to NavCad, and presented at the WMTC2006 Conference in London.

      Effect of shaft angle - High shaft angle can greatly affect a propeller's thrust and torque. Avoid unexpected overload and peak cavitation surprises with a new "inclined flow" algorithm.

      River barge train resistance - A new supplemental calculation for the prediction of river barge trains (flotillas, convoys) has been added.

      Blade scan analysis - Enter local pitch and chord length at a few radii as measured from a blade scanning device, and this utility will help you determine the propeller's EAR and hydrodynamic mean pitch.

      Supplemental calculations - Calculations are now available that are beyond the typical set of resistance and propulsion analyses, now including . The first of these include the prediction of dynamic trim, vessel squat, and synchronous pitching. 

NavCad™ is a software tool for the prediction and analysis of vessel speed and power performance. It also provides for the selection of suitable propulsion system components - engines, gears and propellers. Built from a very comprehensive library of algorithms, NavCad can be used for the design and analysis of virtually any type of monohull or catamaran - from large displacement vessels to fast planing craft .

The Project View contains a tree (much like Windows Explorer) that you can use to quickly open data entry forms and run calculations. It also contains a "snapshot" of the project's principal parameters - such as Displacement, L/B or engine power.

The Performance Summary is a spreadsheet presenting the current system performance. It is a complete look at the results of your project calculations, from resistance all the way through engine power, fuel rate and cavitation. The Performance Summary also underscores the fundamental nature of NavCad™ - where all performance items are related through a Hull-Propulsor-Engine equilibrium.

What vessels can I evaluate with NavCad™ ?

NavCad™ can be used for virtually every type of displacement, semi-displacement and planing craft, river barge, sailboat and catamaran. Towing and free-running analyses are supported, as are a variety of propulsor options.


What makes NavCad™ different ?

NavCad™ is unlike any other resistance and propeller program. Not limited to a few routines for the prediction of one or two aspects of performance, NavCad™ provides a complete platform for the steady-state equilibrium analysis of performance from hull to engine. Features such as the minimum hull drag analysis provide designers with powerful tools to optimize hull forms.

What is the "minimum hull drag" analysis ?

Once hull data has been entered and a resistance prediction built, you can analyze and optimize your hull with the Minimum hull drag analysis. You define search ranges and intervals for significant data items (e.g., length, beam, LCB), and NavCad™ predicts the drag for the configurations and then ranks it. The configuration with the minimum drag is displayed at the top of the list, with the difference from minimum displayed in percent of drag. The calculation also has the ability to review a compromise analysis, using a time-weighted average of two speeds.

 
  Capabilities & New features
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  • New resistance prediction methods for semi-displacement hulls: VTT Round Bilge, VTT Hard Chine, US Navy CRTS, Jin-1988 and enhanced validation of the Mercier semi- displacement method
  • New resistance prediction methods for displacement hulls: Sturtzel & Graff shallow water added drag method for fast monohulls and enhanced data checking for the Holtrop method
  • Optimum trim analysis
  • Expression of added drags as percentages of bare-hull drag
  • Minimum drag analysis
  • Blade impulse pressure
  • Project management: file use monitoring
  • Waterjet propulsion
  • Surface piercing and cycloidal propellers
  • Sinkage & Trim due to squat
  • Azimuthing Thrusters Furthermore, some of the new functions under development are:
  • Conceptual bulb designer
  • Voyage analysis
    Recent publications include:
  • "A universal parametric model for waterjet performance", "Analysis of Vessel Acceleration with NavCad™", "Waterjet Data Files for NavCad™", "Predicting Resistance and Power for an Integrated Tug/Barge Using NavCad™", "Definition of Section Offsets in PropCad", "Typical WorkBoat Rudder and Propeller Placement", "HydroComp Software and Year 2000 Dating", "When Does Shallow Water Become a Problem?", "Modeling Tractor-style Azimuthing Podded Drives"
NavCad™ new function: blade impulse pressure.
This is a prediction of the pressure on the local hull region around the propeller from combined cavitating and non-cavitating pressure impulse of blade frequency.

Blade impulse pressure is a vibration excitation source, and thus is a useful parameter in evaluating the likelihood of noise and vibration from the propeller.

 
  Why Do You Need NavCad ?
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Naval architects, marine engineers, hydrodynamicists and researchers in shipyards, design consultancies, equipment manufacturers, navies and research institutions all rely on NavCad™.

 
    How Does NavCad Work ?
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Prediction accuracy is insured by offering a) the largest available suite of prediction methods (over two dozen for bare-hull resistance alone), b) compatible components between methods, c) calculations built from contemporary state-of-the-art methodologies, d) a complete analysis environment where critical components (like shallow water resistance, for example) cannot be forgotten and e) dedicated evaluation, testing and internal R&D (see MacPherson, D.M., Reliable Performance Prediction: Techniques Using a Personal Computer, SNAME Marine Technology, Vol. 30., No. 4, October 1993).

In addition, NavCad™ contains HydroComp's Method Expert prediction method ranking system. This feature takes your vessel data and ranks all monohull prediction methods based on speed regime, ranges of hull parameters and the availability of hull details (e.g., if waterplane coefficient or trim, for example, has been entered and is used in the method). It also takes into account HydroComp's extensive knowledge about prediction method behavior and reliability. Warnings are raised if a method has shown poor results for the given vessel information.
What propulsor types are supported by NavCad™ ?

NavCad™ greatly extends your propulsor options. In addition to the popular B-series, Gawn and Kaplan propellers, NavCad™ includes surface-piercing and cycloidal propellers, cupped propeller prediction, use of custom Kt/Kq data and the much anticipated waterjets.

Can NavCad™ evaluate cupped propellers ?

NavCad's prediction of cupped propeller performance is based on novel developments from HydroComp's technical staff. The results of this study were presented at SNAME Propellers '97 [MacPherson, D.M., "Small Propeller Cup: A Proposed Geometry Standard and a New Performance Model"]. A version of this prediction technique has been used in HydroComp PropExpert™ for over a year with great success.

How do I use my Kt/Kq model test data ?

New file types have been added to allow you to enter Kt and Kq versus J data from your propeller model tests or wake-adapted calculations. These simple ASCII files are then used as the source of propeller performance for Shaft Power and System Analysis calculations. NavCad™ even properly applies scale correction during the calculations. At the current time, these files cannot be used for Optimum Propeller calculations (since the propeller P/D ratio, number of blades and blade area ratio are already defined).


What kind of support is available from HydroComp ?

NavCad™ includes both on-line and printed User's Guides and Help systems, which can generally answer most questions. In addition, 90 days free maintenance and telephone/fax/e-mail support are included with the purchase. The annual maintenance, support and update (MSU) subscription offered by HydroComp will insure that you continue to receive all updates and in-depth technical support. HydroComp also maintains an extensive library of technical references that can be accessed by users. A quarterly newsletter provides useful hints and suggestions, and on-site or seminar training is available.
Technical support is of course also available through DS&T.

Can I use NavCad™ with my other software ?

NavCad™ is suitable for use either as a stand-alone tool or in conjunction with other naval architectural design software. NavCad's simple parametric hull data makes entry of vessel details very easy. NavCad™ also supports the IMSA open hull data transfer standard (IDF) so that hull data developed in a design or stability program can be exported to NavCad™.



NavCad™ can be run from within other design programs with design data passed to NavCad™ on start up. After completing an analysis in NavCad™, the new optimized hull parameters can be returned to the host program. HydroComp is working with key marine software developers to allow NavCad™ to be run from their systems (such as FastShip) with hull data automatically created and transferred.

In much the same way as NavCad™ can be run from other programs, you can launch other programs from within NavCad™. Standard ASCII-based NavCad™ job files are used as the data exchange format.

Tell me about waterjets in NavCad ?

After a number of years of looking at the problem of waterjets, we concluded that a suitable first-principals solution was not possible. Part of our review included the development of two new coefficients - coefficients which would allow waterjet performance to be defined in a manner suitable for NavCad's ASCII file formats. Through the use of these new coefficients, the waterjet calculation algorithm determines the proper thrust and power for a given speed and equilibrium RPM.

Like all NavCad files, the format for the waterjet files is available from HydroComp. We also provide a Microsoft Excel template to help create waterjet files. Many files are already being made available to NavCad users who are up-to-date on their support and update subscription .

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  What do you need to run NavCad ?
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NavCad™ is a Windows program for use with Windows NT, 2000 or XP. A pentium CPU, 8 Mb ram and 10 Mb of hard disk space is required. Windows 98 can also be used, but is no longer officially supported. With regards to hardware, any modern PC will do.

Who uses NavCad™ ?

As of January 2004, NavCad™ is used in over 450
most respected companies in more than 30 countries.

Link to Hydrocomp inc.

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