Naval Historywith Dr. Alex

Q&A · 44:51-46:11

How large ship propellers are cast and finished

Large marine propellers are preferably cast as one piece, then machined to the precise final form that a mold alone cannot produce.

Marine EngineeringPropellersShip PropulsionShipbuilding
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Question

Are large ship propellers cast in one piece, or are the blades attached to a separately cast hub?

Short answer

A single casting is preferred, followed by substantial milling and finishing because the propeller will not emerge from the mold precise enough for service.

Notes

A single casting is preferred over separately attaching blades to a hub. The foundry creates an oversized near-final form in a large mold, after which machining or milling removes material and corrects the surfaces. Casting supplies structural continuity while precision finishing produces the hydrodynamic shape required in service.