America on the Move | Anchor patent model

Anchor patent model

Catalog #: 308,562, Accession #: 89,797
Currently on display
From the Smithsonian Collection

Elisha Trask Barlow sought to improve how anchors grab the seabed. His design exploits the force of a vessel pulling on the anchor to, in the inventor's words, "induce an effort in the anchor to take hold." This is the model Barlow deposited at the Patent Office with his application in 1869.

Physical Description

Barlow's anchor comprises a two-part main stem (the shank) with curved arms (flukes) projecting from one end. A shackle at the shank's other end provides the fastening point for a vessel's anchor cable. Pivoting metal plates link the shank and flukes together. The model is nickel-plated iron and measures 5 1/2" L x 3 1/2" W x 1 1/2 H. Barlow's name is etched into one side of the shank.

Details

Date Made:

1869

Locations:

California

Note:

San Francisco

Credit:

Transfer from the U.S. Patent Office

History

Many nineteenth-century anchor designs featured pivoting flukes. Barlow's innovation was to link them to a sliding double shank. When strain is placed on the shackle at one end of the anchor, the uppermost part of the shackle is pulled forward, forcing the flukes to rotate down. As the anchor cable tries to drag the anchor forward, the downward pointing flukes are driven into the ground. "This arrangement of the parts of an anchor is most complete," Barlow said, "as the flukes are always governed by the strain on the cable, and [the anchor] can by no possibility become detached from its position when once it is set in the ground, unless a vertical strain should be brought to bear upon it, or the anchor should be turned over by the movements of the ship, in which case it will immediately take hold again."

Barlow, a machinist, lived in San Francisco, California.

Ref:

Elisha Trask Barlow, Anchor, U.S. patent no. 97,342, Nov. 30, 1869

The San Francisco Directory, 1869