Small Versus Large Anchors

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The consensus among anchor makers (Fortress, Bruce, Manson, Mantus) is that holding power in soft bottoms increases in approximate proportion with anchor mass; exponents range from 0.92 to 1.0. While there are differences between models and manufacturers, a 35-pound Mantus should hold roughly 18 times more than a 2-pound Mantus, and a Fortress FX-16 should hold four times more than a Guardian G5.

anchors

If we compare our soft mud 2.5-pound Mantus holding result (35 pounds) with the 45-pound Mantus result (750 pounds), the scale-up error is about 20 percent. The same is true for the Guardian/Fortress comparison and the Claw comparison: about 20-percent scale-up error. The drag-in distance to full holding was proportional to the anchors physical size, a trend supported by U.S. Navy testing; Anchors tested at Solomons Island took 30 to 40 feet to develop full hold, while the small anchors took 4 to 10 feet. These are averages; variations between runs were often 50 percent or more, often due to trash in the mud.

Overall, the burying behavior, turning behavior, and relative holding power of the pint-sized anchors in consistent sand and soft mud is consistently proportional to full-size anchors. In other bottoms, especially those that are hard to penetrate, the results are less comparable.

Darrell Nicholson, editor of Practical Sailor, grew up boating on Miami’s Biscayne Bay on everything from prams to Morgan ketches. Two years out of Emory University, after a brief stint as a sportswriter, he set out from Miami aboard a 60-year-old wooden William Atkin ketch named Tosca. For 10 years, he and writer-photographer Theresa Gibbons explored the Caribbean, crossed the Pacific, and cruised Southeast Asia aboard Tosca, working along the way as journalists and documenting their adventures for various travel and sailing publications, including Cruising World, Sail, Sailing, Cruising Helmsman, and Sailing World. Upon his return to land life, Darrell became the associate editor, then senior editor at Cruising World magazine, where he worked for five years. Before taking on the editor’s position at Practical Sailor, Darrell was the editor of Offshore magazine, a boating-lifestyle magazine serving the New England area. Darrell has won multiple awards from Boating Writer’s International, including the Monk Farnham award for editorial excellence. He holds a U.S. Coast Guard 100-ton Master license and has worked as a harbor pilot and skippered a variety of commercial charter boats.

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