5.1 Direct calculations
may be specifically required by the Rules for Special Service Craft.
They may be required for craft having novel design features, or may
be submitted in support of alternative arrangements and scantlings.
LR may, when requested, undertake calculations on behalf of designers
or Builders and make recommendations with regard to the suitability
of any required model tests. Where model testing is undertaken to
complement direct calculations details would normally be required
to be submitted indicating the schedule of tests, details of the test
equipment, input data, analysis and calibration procedures together
with tabulated and plotted output.
5.2 All direct
calculations are to be submitted for examination. Where calculation
procedures other than those available within the Rules for Special
Service Craft are employed, supporting documentation is to be submitted
for appraisal and this is to include details of the following:
- calculation methods,
- assumptions and references,
- loading data,
- structural modelling,
- design criteria.
5.3 LR will consider
the use of Builder's and/or designer's programs for direct calculations
in the following cases:
- where it can be established that the program has previously been
satisfactorily used to perform a direct calculation similar to that
now submitted,
- where sufficient information and evidence of satisfactory performance
is submitted to substantiate the validity of the computation performed
by the program.
5.4 Where items
are of a novel or unconventional design or manufacture, it is the
responsibility of the Builder and/or designer to demonstrate their
suitability and equivalence to the Rule requirements. Alternative
arrangements, which are in accordance with the requirements of a National
Authority, may be accepted as equivalent to the requirements of the
Rules for Special Service Craft.
5.5 These Guidance
Notes are published to enable designers/Builders to carry out the
Rule calculations without using the Rules for Special Service Craft
software.