Product

Skewed Kaplan Style

combine the high-thrust performance of a traditional Kaplan ducted propeller with advanced blade skew geometry to drastically minimize hull vibration, acoustic noise, and cavitational pressure pulses. Designed specifically for operation inside Kort nozzles and ducted shroud systems, the Skewed Kaplan design maintains tight tip-clearances while smoothing out pressure spikes as the blades pass nozzle support struts and hull structure.

Incorporates progressive blade skewing to distribute hydrodynamic load gradually across the blade span, dramatically reducing hull vibration and underwater acoustic signatures.

Maintains broad tip contours optimized for nozzle interiors, eliminating tip vortex losses to maximize bollard pull and towing efficiency.

Cast from high-impact CF3 (modified 304L) stainless steel or Nibral bronze to withstand severe river silt abrasion, cavitational erosion, and log impacts.

CNC-machined and dynamically balanced to ISO 484-2 Class 1 tolerances, protecting tailshaft bearings, cutless bearings, and reduction gears from cyclic fatigue.

Propeller Model Code	Blade Configuration	Diameter Range	Propulsion Material	Primary Commercial Application
SK-KAPLAN-4B-CF3	4-Blade Skewed Kaplan (Low-Vibration Ducted)	30" to 108"+ (Custom Pitch)	CF3 Stainless Steel (Impact Resistant)	Kort nozzle push boats and river towboats requiring heavy thrust with reduced cabin vibration.
SK-KAPLAN-4B-NIB	4-Blade Skewed Kaplan (Low-Vibration Ducted)	30" to 108"+ (Custom Pitch)	Nibral Bronze (Ni-Al-Bronze)	Ducted harbor tugboats, passenger ferries, and commercial craft demanding smooth thrust.
SK-KAPLAN-5B-CF3	5-Blade Ultra-Quiet Skewed Kaplan	48" to 108"+ (Custom Pitch)	CF3 Stainless Steel (Impact Resistant)	High-horsepower multi-screw ducted push boats operating under maximum continuous load.
SK-KAPLAN-5B-NIB	5-Blade Ultra-Quiet Skewed Kaplan	48" to 108"+ (Custom Pitch)	Nibral Bronze (Ni-Al-Bronze)	Research vessels, ocean-going tugs, and high-spec commercial vessels with strict acoustic limits.

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Design

Custom commercial ducted propulsion propeller featuring progressive blade skew, Kaplan wide-tip geometry, anti-singing edge bevels, and specialized hub castings engineered for Kort nozzles requiring quiet, low-vibration operation.

Application

Low-Vibration Push Boats & Towboats: Commercial river vessels operating under heavy load where crew comfort and hull resonance reduction are critical.
Ducted Ocean & Harbor Tugs: High-bollard-pull tugboats requiring smooth, quiet power delivery during ship-assist and towing maneuvers.
Research, Passenger & Patrol Craft: Ducted commercial or governmental vessels demanding low acoustic signatures and ultra-smooth propulsion.

Materials

CF3 Stainless Steel: Proprietary modified 304L stainless steel formulation offering maximum impact toughness, high fatigue strength, and excellent weld repairability.
Nickel Aluminum Bronze (Nibral): High-density marine alloy providing outstanding cavitational erosion resistance and smooth hydrodynamic surface finishing.

Construction

Precision Machined Hub & Bore: Custom SAE or Metric taper shaft bores CNC-machined and verified with calibrated plug gauges for precise fitment to the propeller shaft.
Skewed Anti-Singing Trailing Edges: Beveled trailing edges integrated with skewed blade contours to eliminate harmonic acoustic singing and resonance inside the nozzle shroud.
Dynamic Balancing: Dynamically balanced to ISO Class 1 specifications to prevent tailshaft stress, stuffing box wear, and cutless bearing failure.

Scope of delivery

Custom Kahlenberg Skewed Kaplan Propeller: Machined, polished, and balanced ducted propeller tailored to custom nozzle dimensions, pitch, and shaft bore specs.
ISO Class 1 Inspection Certificate: Pitch verification, blade thickness report, bore taper check, and dynamic balance certification.
Documentation: Installation instructions, shaft keyway alignment sheet, and Kahlenberg factory warranty paperwork.

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