It’s a boating question that’s been around for ages: Which anchor works best? Ask that question among any reasonably equipped group of boaters and you’ll get as many different replies as there are people. And while anecdotal testimonials are good enough for most folks, others prefer hard scientific data.
That’s where Fortress Anchors, a manufacturer of lightweight, aluminum alloy, Danforth-type anchors, comes in. The company has done more independently assessed anchor testing over the last two decades than just about any other, starting with the Fortress Anchor Tests in Biscayne and San Francisco bays in 1990. In these two places the company used a tugboat to yank several popular anchors into the bottom, and then measured how much force it took to pull out each one.
With today’s global economy, there are more brands and types on the market than ever—and not just those made by the once-dominating names of Danforth, Bruce, or CQR. Ever heard of a “Mantus,” “Supreme,” or “Boss” anchor? That’s OK; neither had I.
It’s this modern anchor invasion that prompted Fortress to conduct a new round of testing, to see how these relative newcomers measure up. As for location? Fortress’ Brian Sheehan said, “The soft mud bottom of the Chesapeake is especially challenging for anchors. This made it an obvious first choice for these tests.”
The tests—dubbed the 2014 Chesapeake Bay Anchor Holding Power Test—got underway in Solomons, MD, under the watchful eyes of about a dozen critical and very opinionated marine journalists (including me), who were there to make sure there wasn't any Fortress funny business.
The amount of boating knowledge gathered on the dock the first morning was humbling: we estimated that among us there was easily more than 300 years of boating experience assembled. Also present was Chuck Hawley, former vice president of product testing at West Marine. Hawley would serve as an independent reviewer, and he also helped to develop the testing protocol with which the anchors would be tested.
Our test platform for the 2014 tests wasn’t a big, twin-engine tug, but the University of Maryland Center for Environmental Science’s research vessel Rachel Carson. Now make no mistake, Rachel Carson has the brute strength to rip some anchors through the mud with her twin, 1,200-horsepower MTU diesels, but it was this vessel's oceanographic winch and Kongsberg cPos Dynamic Positioning System that made her so valuable for our testing.
On our way out to the Patuxent River testing area, Hawley described the testing protocol that we’d be using to evaluate each anchor. We’d test eleven different anchors five separate times in five unique locations (datums). To eliminate the possibility that an anchor would be dragged through the ditch plowed in the bottom by a previous anchor test, each one would be pulled in a different compass direction from the center of every datum. The rode consisted of 20 feet of 3/8-inch, high-test chain and a length of 5/16-inch 7x19 wire rope, which was wound onto the Rachel Carson’s oceanographic winch.
After each anchor had been deployed to the bottom, enough rode was paid out so that a 5:1 scope was achieved. Following that, an additional 100 feet was let out to achieve an initial scope of around 8.3:1. With a suitable amount of rode paid out, the Rachel Carson’s dynamic positioning system was engaged to keep her set in one place on the water, and the oceanographic winch then hauled back the anchor rode at a precise speed of 10 feet per minute. That gave each hook 10 minutes’ worth of time to engage the bottom. A device called a running line tensiometer recorded rode tension, in pounds.
While it took us all a few hours to understand what we were seeing on the flat-screen monitors situated around the Rachel Carson, patterns began to emerge, and after a few days there were clear performers and under-performers among the group.
Generally, the Danforth-type anchors performed the best in the deep, goopy mud. The 35-pound Danforth High-Tensile displayed a tension of around 1,400 pounds, while Fortress’ FX-37 dug in to a whopping 2,100 pounds. There’s a reason Danforth anchors have a reputation for good performance in mud, and the tests show why.
Most of the other anchors displayed what could be called “average” performance. The most consistent of the group were the 45-pound Mantus and 46-pound Ultra anchors. The Mantus peaked at around 850 pounds, while the Ultra dug in up to 1,100 pounds. Included in the “average” group were the Claw (ex-Bruce) and CQR, with 200 to 400-pound steady results and peaks around 800 pounds.
We were all a bit surprised by the performance of the 44-pound Delta and the 44-pound Rocna, both of which have good reputations among cruising boaters. The Delta appeared to set reliably to around 300 pounds, but often quickly dropped off when the scope shortened. The Rocna behaved in a similar fashion. That said, both anchors did set at some point and held up to about the 700-pound mark.
To give all of these results some scale, Fortress recommends an anchor capable of 900 pounds of holding power to hold a 35-foot boat with average beam and windage in 30 knots of wind. A 40-footer needs 1,200 pounds and a 50-footer requires 1,600 pounds.
Phew! That’s a lot of data, and while I could certainly go on for hours about the one or two possible limitations in the testing protocols, it’s obvious that a Danforth-type anchor is your best bet in muddy bottoms. A Danforth anchor may not be the easiest of the group to stow and deploy from a bow platform, but it's the one I'd have on my bow when I want a good night’s rest on the hook in Chesapeake Bay.