Section 3 Equivalents
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Naval Ships, January 2023 - Volume 1 Ship Structures - Part 3 Design Principles and Constructional Arrangements - Chapter 1 General - Section 3 Equivalents

Section 3 Equivalents

3.1 Alternative arrangements and calculation methods

3.1.1 In addition to cases where direct calculations are specifically required by the Rules, LR will consider alternative scantlings which have been derived by direct calculations in lieu of specific Rule requirements. All direct calculations are to be submitted for examination.

3.1.2 Where calculation procedures 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;
  • structural modelling;
  • design criteria and their derivation, e.g. permissible stresses, factors of safety against plate panel instability, etc.

3.1.3 LR will be ready to consider the use of Builder’s programs for direct calculations in the following cases:

  1. Where it can be established that the program has previously been satisfactorily used to perform a direct calculation similar to that now submitted.

  2. Where sufficient information and evidence of satisfactory performance is submitted to substantiate the validity of the computation performed by the program.

3.1.4 Alternative arrangements or fittings which are considered to be equivalent to the Rule requirements will be accepted, in accordance with Vol 1, Pt 1, Ch 2, 3.2 Tailoring – Departures from the Rules and Rule additions.

3.1.5 Where no special reference is made in this Part to specific requirements, the construction is to be efficient for the intended purpose and to conform to good practice.

3.1.6 Where items are of a novel or unconventional design or manufacture, it is the responsibility of the designer to demonstrate their suitability and equivalence to the Rule requirements.


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