Overview
ISO 23453:2022 - Ships and marine technology - Guidelines for the design and manufacture of the hub cap with fins (HCWF) for a fixed‑pitch marine propeller - provides general, practical guidance for designing, testing and manufacturing a hub vortex energy‑saving device that replaces a conventional propeller hub cap. The standard covers hydrodynamic design procedures, manufacturing and surface‑finish recommendations, tightness and strength checks, and methods to verify energy‑saving performance (model tests, CFD and full‑scale trials).
Key topics and technical requirements
- Purpose: Reduce energy losses from propeller hub vortices and improve propulsion efficiency; also helps reduce underwater noise.
- Applicability analysis: HCWF is particularly suited to fixed‑pitch propellers and propellers with high root loading; designers assess applicability by experience and analysis.
- Geometry & positioning: Early design parameters include axial distance (L), circumferential phase angle (ψ), HCWF diameter (D), number of fins, chord and thickness, rake and skew distributions.
- Hydrodynamic design: Pitch and camber distributions should be established using potential‑flow coupled with viscous‑flow theory, CFD or equivalent methods.
- Performance verification:
- Use CFD supplemented by model tests and full‑scale verification.
- Model testing examples include reverse propeller open‑water test (Reverse POT) in cavitation tunnels, circulating channels or towing tanks.
- Correction and comparison procedures are provided to derive corrected open‑water coefficients and efficiencies.
- Manufacture & materials: HCWF material should match propeller material and comply with relevant IACS and propeller specifications (IACS UR W24 referenced). Surface finish and tolerances are recommended to follow ISO 484‑1 / ISO 484‑2 as applicable.
- Tightness test: Inner chamber must withstand hydrostatic or air pressure > 0.2 MPa for > 30 minutes, maintaining ≥ 90% of test pressure with no leakage.
- Strength checks: Structural strength can be validated per classification society propeller specs or by FEA; blade thickness guidance specifies checks at 0.6×radius under 5% MCR.
- Fastenings: Connecting bolts must be corrosion‑resistant, sufficiently strong and incorporate anti‑loosening measures.
Applications and users
Who uses ISO 23453:2022:
- Naval architects and ship designers assessing propulsion upgrades or newbuild designs
- Propeller and HCWF manufacturers developing energy‑saving devices
- Shipyards performing installation and maintenance
- Classification societies and surveyors reviewing compliance and strength checks
- Propulsion engineers and R&D teams validating CFD and model tests
Practical uses:
- Retrofitting merchant ships to improve fuel efficiency and reduce underwater noise
- Specifying manufacturing and test procedures for HCWF production and acceptance trials
Related standards
- IACS UR W24 - Cast Copper Alloy Propellers
- ISO 484‑1 / ISO 484‑2 - Ship screw propellers - Manufacturing tolerances
- ITTC recommendations on unconventional propulsors (1999)
Keywords: ISO 23453:2022, hub cap with fins, HCWF, hub vortex energy‑saving device, fixed‑pitch marine propeller, hydrodynamic design, CFD, open‑water test, propeller manufacturing.
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