Section 1 General

1.1 Upon application to LR for General Approval of a longitudinal strength and stability calculation program, two approaches are available to the loading instrument manufacturer. Firstly, where the manufacturer already has loading instrument software for an LR Classed ship the program may receive General Approval on the basis of the examination of that ship, although the extent of the approval will be limited to only those functions examined and to a particular ship type. The ship particulars required to be submitted in this case would be as outlined in paragraph Ch 1, Ch 4, 2 Appraisal of Test Conditions for Longitudinal Strength Aspects 2.1.

Alternatively, LR will provide the applicant with test data for three different ship types. This test data is to be input to the program and the results obtained, (together with the hydrostatic and cross curve data developed by the program, if appropriate) is to be submitted to LR for checking computational accuracy against the results obtained from LR's parallel calculations using the same input data. Where the calculation process involves interpolation which could lead to tolerance differences in repeat calculations, the tolerance limits are to be advised.

1.2 Where a program has been written for a single application only, i.e. a unique program for a specific ship, or in those cases where the software is not available for general use, the General Approval procedure will be specially considered by LR London.

1.3 In all cases where a program has been developed to carry out grain stability calculations from first principles, a hull form definition must form the basis of the calculation. Where actual maximum allowable grain heeling moment data is utilised a hull form definition is not required. In the latter case, the program is to contain sufficient data such that compliance with the relevant grain stability regulations is accurately determined for the vessel in any anticipated loading condition.

1.4 Automatic assessment by the program of the results of the calculations against relevant criteria and other operational limits is considered essential since assessment by the operator could introduce error.

1.5 A clear and concise user’s manual is to be submitted for review. An English translation of the manual is to be provided if the original is in another language.

1.6 Details of the minimum specification of the hardware on which the program will be run is to be provided.

1.7 The manual must clearly show the program name and version number.

1.8 Details of any calculation tolerances in the program and their specific values should be stated.

1.9 Program disks are to be provided for use as part of LR’s examination.

1.10 It is recommended that the program should have a simple command (keystroke/icon) that returns the user directly to a familiar “home” screen from any of the loading screens. This allows a “lost” user (who may have got disoriented among various loading screens) to re-establish their orientation quickly.

1.11 The program should have easily accessed “help” functions such as designated function keys or an on-screen menu bar.

1.12 A default loading condition should reflect any special loading or operating requirements imposed by the ship‘s stability booklet (such as locked-in ballast requirements).

1.13 The program should check that data entered by the user is reasonable so that possible input errors are identified - for example, a cargo tank entry which exceeds the maximum capacity of the tank. Similarly, the program should alert the user if an output parameter such as “predicted GM” is out of expected bounds.

1.14 The system should alert the user if an output indicates a critical or possibly dangerous situation. It is recommended that warnings should, where possible, be augmented by audio signals. It is also recommended that the graphical presentation and audio signals are different, in case of critical events and user errors.

1.15 In most cases, load entries will be of the fixed-location type where LCGs, VCGs etc are pre-displayed and the user needs only enter a weight value. However, the program should include the facility to allow additional non-fixed load entries where the user can enter its longitudinal extent along with VCG, LCG, TCG etc. Examples of non-fixed load entries might be an unusual temporary deck cargo.

1.16 Each loading condition print-out should automatically contain the name of the ship, program name with associated version number and the date of the print-out, along with a title for the condition. This information should be repeated on each page of the print-out.

1.17 Once the above information has been submitted and the program’s calculations, program functionality and user’s manual are considered satisfactory, LR will issue a "Certificate of Approval", (See Figure 1.7.3 Certificate of Approval).

1.18 It should be noted that any changes to the program which affect either the longitudinal strength or stability calculation aspects must only be made by the software manufacturer or his representative and that Clasification Society MUST be informed immediately since such changes may invalidate any certificate issued. In cases when the approval certificate is considered to be invalidated, approval of the new program will be carried out in accordance with the procedure in this booklet.

1.19 It is recommended that the program be designed and produced in accordance with appropriate quality standards (e.g. ISO 9000-3 or equivalent), in order to demonstrate that the software operates correctly for cases other than those for which LR has checked computational accuracy. Certification in accordance with LR’s Software Conformity Assessment System will be considered to satisfy this requirement.

1.20 Users should be allowed to enter or modify only operational parameters (such as loading data or display formatting options). The basic software and its configuration data for a specific vessel (such as hull structural data) should only be capable of modification by the manufacturers or other authorised persons notified in advance to Clasification Society, and should be protected from unauthorised modification by suitable means such as passwords or encryption.