Minimum Shaft Diameter Calculation for Propeller Shaft

This tool allows you to calculate the minimum diameter of the propeller shaft based on the transmitted power, rotational speed, shaft type (solid or hollow), and the mechanical properties of the material used.

The calculation is based on a technical formula recognized in the marine industry, which takes into account key parameters of strength and structural safety, in order to ensure the reliability of the shaft under continuous operating conditions.

Minimum Shaft Diameter Calculation







Minimum shaft diameter:

-- mm
Disclaimer

The data and calculation tools presented in this section are provided by ENAVE for informational purposes only. ENAVE does not guarantee the formal or substantive accuracy, nor the updating of the data, reference standards, calculations, or results contained herein.
All content should be considered indicative and non-binding, and cannot in any way replace a design calculation performed by a qualified professional.
The use of these tools for purposes other than information is entirely at the user’s own responsibility.

 

Coefficient Values

  • 82 for intermediate shafts without keyways, equipped with full flange couplings or clamp-type couplings without key.
  • 90 for intermediate shafts with keyways (e.g., for non-full flange couplings).
  • 104 for propeller shafts made of corrosion-resistant steel or propeller shafts with continuous bronze cladding or an effective oil lubrication system.
  • 109 for propeller shafts with continuous bronze cladding in contact with seawater.
*Values of the Rm coefficient
MaterialMaterial grade/codeRm (N/mm²)
Carbon steelFe 37/360
360
Carbon steelFe 43
430
Carbon steelFe 510
510
Stainless steelAISI 304
500/700
Stainless steelAISI 316
500/700
Stainless steelAISI 410
730
Stainless steelAISI 420
800
Stainless steelAISI 430
400/600
Stainless steelAISI 630
1270
Stainless steelAquamet 17
931
Stainless steelAquamet 22
1000

For the purposes of the calculation, the maximum usable value of Rm is 930 N/mm².

The result returns the minimum shaft diameter (d) in millimeters, required to ensure adequate mechanical strength and long-term durability.

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