THE CTX TANKER SOFTWARE LIBRARY

Preamble

This effort is not really a project. Rather it is a set of rules for ensuring that the work of all the CTX software projects can be easily re-used and extended. These rules are also aimed at insuring that the source code can be easily scrutininzed and checked by any interested party. CTX's view is that any programming that purports to be in the public good, especially programming which claims to ensure that a tanker is being legally designed or operated should be subject to third party review and inspection. Currently, this is not the case. All the programming that is used in tanker design and operation is proprietary. Nobody other than the authors has any idea how it works nor what the bugs are. Nor is there any reasonably reliable system for exposing those bugs. CTX personnel have stumbled on several major, long standing bugs in standard tanker design and loading programs, but we can be sure that as long as the source code is unavailable for every bug that is discovered, a score or more will not.

The various CTX projects will generate a great deal of software. At a minimum these will include:

CTX_MATE

This program will be a re-write of the existing MLOAD package which inter alia does tanker hydrostatics, tank tables, longitudinal strength, intact stability, damaged stability, flooding, sloshing resonance, intact and damaged transverse section modulus, cargo survey report generation, Effective Oil Spill calculation, 13G7 HBL calculation, and actual oil outflow for a given damage location. This program exists and is in daily use by two big tanker owners. However, currently it does not do a good job of modelling spillage in many double hull casualty scenarios. The program needs to be extended to include the impact of the double sides as a spill containment device in the event the damage does not extend to the top of the side shell. It also needs to be extended to handle the improved standard casualty scenario. Needs to be totally rewritten and organized into classes. Needs to be integrated with CTX_HULL and CTX_3D.

CTX_HULL

CTX_HULL will perform full hull finite element calculations and display them. Bits and pieces of this capability exist but needs to be put together.

CTX_3D

CTX_3D which will be a three-D visualization package for tanker loading and spillage purposes. Only bits and pieces of this exist. Intention is to use the VTK visualization tool kit. Needs to be closely intergrated with CTX_MATE.

CTX_KIT

CTX_KIT is the glue that combines the other programs into a tanker design and analysis program based on the vessel's dna.pl file. This will be an extension of the existing MKIT package. We will need to beg, borrow, steal, develop, an Open Source CADCAM package. This will be used by the students in their design work and extended as required. Must interface with CTX_MATE, CTX_HULL, and CTX_POWER at a minimun.

CTX_IMO

A new package to implement an improved standard casualty scenario. Starting from scratch but will be very easy to write. The hard part is deciding on the standard scenario.

CTX_SHAFT

A shafting design and alignment package. Bits and pieces of this exist. The first phase goal will be an Open Source version of the BV program.

CTX_PURGE

CTX believes that all double hull spaces should be inerted as a matter of law. This raises the issue of safely purging these spaces for inspection. CTX_PURGE will computes gas flows in double hull ballast spaces for purging and inerting purposes. This progam will be built on Mike Kennedy's VENT2D. All we need is a better user interface.

CTX_POWER

For a variety of design purposes, we need a good model of tanker resistance/propulsion in given sea state. And the corresponding ship motions. Goal is a virtual towing tank. We need to use or build on one of the existing ship motions programs.

EPILOGUE

And hopefully many more.

All this software will be organized into a set of classes which will allow the individual functions to be combined and extended in an efficient manner.

One obvious application is a combination of CTX_MATE and CTX_HULL to get around the severe and potentially misleading problems of using beam theory in damage situations. The concept of using finite element to compute stresses in routine loading sitations may not yet be quite computationally feasible. But it certainly will be within five years. (One short-run possibility here is a coarser FE Model, with a mesh similar to the Safehull system, that is about 4 m by 4m. Such a model with some 30,000 nodes could easily be used in routine loading situations right now. The issue the CTX will have to explore is whether or not it is worth maintaining both a fine mesh and a coarse mesh model.)

Further by following a set of standard software rules, the Center's code can be more easily used by third parties including owners, charterers, environmental groups, etc.