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Debrief has been created to perform a variety of functions related to maritime tactical analysis, ranging from detailed analysis requiring accurate calculation and presentation of bearing and bearing rates, through the collation of graphical information to produce a plot for insertion into an analysis report, to the recording of animated dynamic sequences for replay in a presentation. The tool was originally produced to support submarine analysis, but has been expanded over the years to support surface and airborne analysis.  But, in its current version Debrief provides little support for analysis of land-based exercises – significantly it lacks a digital terrain model.

Debrief was originally produced in 1995 in the Maritime Warfare Centre to act as a desktop viewer for results produced by the ASSET submarine simulator. In use, it quickly became apparent that real exercise data could also be viewed in the application, removing the requirement for clerical staff to produce paper plots for use in analysis. The initial version of Debrief was a 16 bit MS Windows C++ application.

Debrief was updated in 1997 to 32 bits, in order to exploit the richer user interface components available for 32 bit Windows applications. It was at this stage that the application was demonstrated and subsequently issued under license to COMSUBDEVRON 12 of the US Navy.

In 1999, development towards Debrief 2000 was started. Over the previous four years a number of fresh requirements had arisen, requirements which could not be economically met using the existing architecture. Accordingly the Debrief 2000 application started with a clean sheet, adopting a modern modular approach to allow incremental implementation and insertion of future modules as they are required. The rapid maturity experienced by Java™ together with the availability of cheaply available development environments and rich application libraries (Serialisation, Java3D and XML in particular), and its platform independence made Java the natural choice for the application.

At the end of 2000, Ian Mayo, the developer and project manager of Debrief, left full-time contracting at the Maritime Warfare Centre to setup his own software development consultancy, PlanetMayo Ltd.

A competitive open tender process was conducted during late 2001 to supply the Maritime Warfare Centre with Debrief support. The contract was won by PlanetMayo, who grouped up the implementation of the MWC’s fresh requirements in a major update to Debrief, titled Debrief 2001. This update bought new, large areas of functionality to Debrief including vectored chart data, display of narrative text, and display of sensor-data.

Support for Debrief from PlanetMayo Ltd continued through 2002, with the company providing bug-fix and user support, followed by the update to Debrief 2002 in Summer 2002. The major new areas of functionality in Debrief 2002 were a gridded bathymetry and a ground-up re-implementation of 3d plotting.  By 2005, Debrief was again reaching the limits of the underlying architecture.  Accordingly Debrief NG was developed, which changed Debrief from being a standalone application to one that sits on top of IBM’s Eclipse framework.  From this broad-capability foundation, Debrief has continued to grow.

Debrief was never been produced with the intention of commercial exploitation; it was been created to meet the analysis requirements of the MWC. With the growth in popularity and size of the Open Source Movement, it has become apparent that Debrief was an ideal candidate for such status; MWC did not seek to make financial gain from Debrief, but would clearly benefit from its wider exploitation; largely for the following reasons:

  • Its open use allows a greater volume of usage, leading to more rapid discovery and correction of bugs, improving the application.
  • Encouragement of the adoption of standard file formats, easing file interchange between national and international analysis partners.
  • To spread the reputation of the MWC as a forward-thinking organisation adopting the most productive and efficient methods in the production of the tools it relies on.
  • There are economic advantages to be gained by third-party users extending and improving the application. The licensing policy means that improvements to the application will normally be released openly, allowing MWC to exploit new functionality when applicable.

Debrief is the major analysis and replay tool used for submarine analysis within the Royal Navy’s Maritime Warfare Centre. It is also used to varying degree by the Surface and Aviation divisions, as they experience the need for a cheap, accessible desktop analysis tool.

Elsewhere in the UK Debrief is in use, or has been used within DSTL, SSPAG and BAe.

Internationally, the Dutch NLANTAC, together with the American VX-1 and NUWC organisations hold and use Debrief. The major international user of Debrief, however, is COMSUBDEVRON 12 in Groton, CT. COMSUBDEVRON 12 have been a significant partner in the development of all of the versions of Debrief, providing a great wealth of information on bugs and usability improvements.

More recently Debrief has been adopted by Poseidon Simulation AS in Norway and within the Virtual Ship Project at Defence Science and Technology Organisation, Australia.

In 2002, the NUWC in the US adopted Debrief, modifying the source code to provide additional functionality required for submarine track reconstruction.


In Summer 2000 the Maritime Warfare Centre committed to switching the Debrief application to Open Source status. The adoption of the Open Source licensing model affected MWC in a number of ways:

  1. Organisations that are currently using Debrief will have full access to the source code of Debrief, allowing them to identify and correct bugs provided they have sufficiently trained staff. The licensing is such that these modifications may be made public through the re-insertion into the central, online “code base”.
  2. Organisations that are not currently using Debrief also have full access to the application and its source code. Since the application and its supporting documentation clearly describe its origins in MWC this will spread the name of the organisation together with enforcing its reputation as a centre of maritime tactical analysis.
  3. Any organisation using Debrief that identifies a bug/algorithmic problem is able to independently correct the problem and submit the corrected code back into the central “code base”. In time, this will greatly increase the accuracy and reliability of the application. MWC may then freely utilise these improvements, only incurring the administrative overhead of “checking-in” code modified by third party organisations.
  4. The free, open source status of the application makes it easier for third party, commercial organisations to bid for development contracts to maintain or extend Debrief. This wider availability will only bring economic advantages to MWC and fellow organisations.
  5. The wider national/international use of Debrief will also lead to easier exchange of exercise data between nations (through common file formats) and potentially offer an increase in efficiency and the general quality of naval exercise analysis

The Debrief 2000 application is free to use, although no support or warranty is provided by either the Maritime Warfare Centre or PlanetMayo Ltd. Additionally, the complete source code for Debrief is freely available through the GitHub site.

Until 2014 PlanetMayo Ltd was contracted to support the Maritime Warfare Centre, and to provide initial support to organisation wishing to adopt Debrief. Organisations which have adopted Debrief can gain further assistance from PlanetMayo Ltd through a Debrief Support Contract.

Yes, it is downloadable from the Files section of GitHub, accessed via the Debrief home page.

The Debrief administrator is currently responsible for the checking-in of modified source code, to allow some quality control management in the early stages. The administrator can be approached via the Debrief Summary page on GitHub if special arrangements are required (such as in the implementation of significant changes). In the future it is intended that additional administrators be appointed as and when suitable candidates are identified.


For a start, you can explore this web site. The Features page provides a breakdown of what Debrief is able to do, whilst the Tutorial page will give you an simulated run-through of the application.

If you’re definitely interested, from the Debrief home page you can navigate to the download page on GitHub and download a Debrief installation (it’s around 160Mb, including the Help file and World coastline, and another 26Mb with the world-wide Natural Earth dataset).

If your questions remain unanswered, then try the following:

  • For a question relating to the development or use of Debrief, use the Feedback Form

Try dropping an e-mail using the Feedback Form, ensuring that you specify what operating system and platform you are using, together with any diagnostic information you think may prove useful.

The data file formats supported by Debrief are described in detail in the Debrief help file, part of the default installation. It is normally quite simple to convert your data to the Replay file format, which is a flat-file text format. Alternatively, if you have more structured data, it may be more suitable to use XSL to create an XML file in the Debrief plot file format.

Once you are ready to commit to the use of Debrief in your analysis, it may be time to consider a more stream-lined approach to handling your data. You can consider amending your data extraction/handling application to output files in one of the Debrief data formats, or you could consider adding a new import filter to Debrief. The open-source nature of Debrief facilitates this addition by allowing you to write either the code yourself – or pass it to a favoured software developer. The Project Lead can provide guidance in the identification of software developers.

The Bug database for Debrief on the Debrief summary page has provision for requests for new/changed features in addition to new bugs, your extra functionality may already be listed on this page, with details of how/when it is to be added.

If you have the Java development skills necessary to make the correction yourself, once you have created your own account within SourceForge you are able to download the Debrief source code and make the correction on your own computer, before uploading the corrected file. It would still be useful to put the details of the bug and its fix on the bug database so that other users are aware of them – it may just save somebody a wasted afternoon.

Go to the Bug database, there’s a link to it from the Debrief home page. First look to see if the bug has been reported already. If so, see if you are able to add any additional information to the bug report, or raise it’s priority. If the bug isn’t reported already, then add it. Details of the new bug are automatically forwarded to the administrators and developers, with fixes being uploaded sometimes as soon as 20 minutes later.