Section 5 Documentation required for design review
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Naval Ships, January 2023 - Volume 2 Machinery and Engineering Systems - Part 4 Propulsion Devices - Chapter 1 Propellers - Section 5 Documentation required for design review

Section 5 Documentation required for design review

Parent topic: Chapter 1 Propellers

5.1 Documentation

5.1.1 Particulars of the propellers are to be submitted with the plans, in triplicate, as described in Vol 2, Pt 4, Ch 1, 5.2 Plans to Vol 2, Pt 4, Ch 1, 5.3 Calculations and information.

5.2 Plans

5.2.1 Plans of the propeller, together with the following particulars, are to be submitted:

  1. Maximum blade thickness of the expanded cylindrical section considered, in mm, excluding any allowance for fillet, T, in mm.

  2. Maximum shaft power (see Vol 2, Pt 1, Ch 2 Requirements for Machinery and Engineering Systems of Unconventional Design), P, in kW.

  3. Estimated ship speed at deep draught in the free running condition at maximum shaft power and corresponding revolutions per minute (see Vol 2, Pt 4, Ch 1, 5.2 Plans).

  4. Revolutions per minute of the propeller at maximum power, R.

  5. Propeller diameter, D, in metres.

  6. Blade section nose-tail pitch at 25 per cent radius (for solid propellers only), P0,25, in metres.

  7. Blade section nose-tail pitch at 35 per cent radius (for controllable pitch propellers only), P0,35, in metres.

  8. Blade section nose-tail pitch at 60 per cent radius, P0,6, in metres.

  9. Blade section nose-tail pitch at 70 per cent radius, P0,7, in metres.

  10. Length of blade section of the expanded cylindrical section at 25 per cent radius (for solid propellers only), L0,25, in mm.

  11. Length of blade section of the expanded cylindrical section at 35 per cent radius (for controllable pitch propellers only), L0,35, in mm.

  12. Length of blade section of the expanded cylindrical section at 60 per cent radius, L0,6, in mm.

  13. Rake at blade tip measured at shaft axis (backward rake positive, forward rake negative), A, in mm.

  14. Number of blades, N.

  15. Expanded area ratio, B.

  16. Material: type and specified minimum tensile strength.

  17. Skew angle, θs, in degrees, see Figure 1.1.1 Definition of skew angle.

  18. Connection of propeller to shaft, details of fit, push up, securing.

  19. Keyed connections details.

  20. Details of control/hydraulic system and pressures for controllable pitch propeller actuating mechanisms.

  21. Inertia of propeller assembly, specified either as GD2 or Wk2, in kgm2.

  22. Total mass of propeller assembly, in kg.

5.2.2 The design operational service profile for the life of the ship is to be submitted. For fixed pitch propellers, this data is to be supplied in terms of a table or histogram showing the proportion of time anticipated to be spent within a particular speed range from zero to full speed. In the case of controllable pitch propellers, the combinator diagram is to be submitted and this is to show the propeller rotational speed, blade pitch angle at 0,7R and power absorbed against the control lever position. Additionally, for these types of propeller the proportion of time planned to be spent at a particular rotational speed, between the minimum and maximum speed ranges, is to be specified in terms of a histogram or table.

5.2.3 For blades of fixed pitch propellers with skew angle of 30 degrees or greater, the stresses in the propeller blade during astern operation are not to exceed 80 per cent of the propeller blade material proof stress. Consideration is to be given to failure conditions and a factor of safety of 1,5 is to be attained using an acceptable fatigue failure criteria. Documentary evidence confirming that these criteria are satisfied is to be submitted.

5.2.4 For propellers having a skew angle equal or greater than 50°, in addition to the particulars detailed in Vol 2, Pt 4, Ch 1, 5.2 Plans 5.2.1 and Vol 2, Pt 4, Ch 1, 5.2 Plans 5.2.2, details are to be submitted of:

  1. Full blade section details at each radial station defined for manufacture.

  2. A detailed blade stress computation supported by the following hydrodynamic data for the estimated ahead mean ship effective wake condition and when absorbing full power:

    1. Radial distribution of lift and drag coefficients, section inflow velocities and hydrodynamic pitch angles.

    2. Section pressure distributions calculated by either an advised inviscid or viscous procedure.

5.2.5 Where propellers, as defined in Vol 2, Pt 4, Ch 1, 1.1 Application 1.1.4, are intended for more than one operating regime, such as towing duties, a detailed blade stress calculation for each operating condition, indicating the rotational and ship speed, is to be submitted for consideration.

5.2.6 Where it is proposed to fit a fixed pitch propeller to the screwshaft without the use of a key, plans of the boss, tapered end of screwshaft, propeller nut and, where applicable, the sleeve, are to be submitted.

5.2.7 Where it is proposed to use a controllable pitch propeller, calculations are to be submitted which demonstrate the design integrity of the pitch control mechanism contained within the hub. Details of the associated piping arrangements are to be submitted. The submission is to include justification for the selection of the associated sealing arrangements within the hub, see Vol 2, Pt 4, Ch 1, 7.5 Propeller boss and hubs 7.5.3.

5.3 Calculations and information

5.3.1 In cases where the vessel has been the subject of model wake field tests, a copy of the results is to be submitted together with details of the model dimensions, scale and test conditions.

5.3.2 The following information is to be submitted as applicable:

  1. For controllable pitch propellers, plans (in diagrammatic form) of the hydraulic systems together with pipe material and working pressures.

  2. Details of control engineering aspects in accordance with Vol 2, Pt 9, Ch 7 Control, Alerts and Safety Systems

  3. Calculations or relevant documentation indicating the suitability of all components for short-term high power operation. Where undertaken, fatigue strength analysis of components indicating a factor of safety of 1,5 at the design loads.

  4. For cases where the propeller material is not specified in Table 1.6.1 Materials for propellers, details of the chemical composition, mechanical properties and density are to be provided, together with results of fatigue tests in artificial sea water (3 per cent NaCl) to enable a value for U to be assigned.

5.3.3 Methods for demonstrating compliance with requirements for class notations AP1 and AP2 are to be submitted where applicable.

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