Over 150 years of expertise in marine railways and floating dry docks

Crandall Dry Dock Engineers
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Bilge Block Systems

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Movable block systems

Bilge block winches

Bilge block chain

Garboard shell assemblies

Upright shell assemblies

Replacement sheaves

Bilge block hinges


Crandall adjustable sliding bilge block systems have been used by shipyards throughout the world for decades. The system consists of crank-driven cast iron winches secured to mounting plates attached to stands located atop the cradle uprights (or atop the wing wall of a floating dry dock). Upright shells located at the upright base at deck level serve as idlers fairleading specially calibrated proof-coil bilge block chain to the bilge blocks. Since the chain is arranged in an endless system, the return movement is accomplished by the use of garboard shells located adjacent to the drydock centerline. Crandall sliding bilge block systems can be operated either from both docking platforms of a marine railway or, in teh case of railway dry docks with side transfer capabilities, special equipment is available for operation from one side only. For floating dry docks, the wing wall or offset back from the face of the wing wall so as not to interfere with line handling, crane rails or other equipment. The winch stand sprocket can be operated by a hand crank or power drive. A ratchet and pawl mechanism on the winch provides a positive lock for holding the chain stationary.



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Crandall Dry Dock Engineers, Inc.
Established 1854
(888) DRYDOCK crandalldd@aol.com