Product Test: Heavyweight Cruising Anchors for Challenging Anchorages
Two roll-bar anchors and one Bruce-style anchor face a battery of tests to see which sets the best.
One of a cruising anchor’s most important traits is its ability to set easily (and reset after a wind shift) in the widest possible variety of bottoms. For those who can carry extra large anchors, holding power, the normal parameter measured by anchor tests, is not as important as setting performance. Once set, an oversized anchor should easily have sufficient holding power. With that in mind, this comparison focuses not on ultimate holding power but the ability of the anchors to set quickly—even in difficult bottoms and with short scope—and to stay set when conditions change. Practical Sailor tested the rollbar-style Manson Supreme and the Rocna as well as the Bruce-inspired Manson Ray claw anchor. Testers looked at each anchor’s design and measurements, as well as its setting and veering performance on a frozen-sand beach covered with large rocks and on a sand/ mud beach. Practical Sailor encourages readers to weigh these results along with those of previous tests on more typical bottoms before selecting a primary anchor.
One of most significant investments a sailor can make is in ground tackle. This is especially true for cruising sailors, who inevitably find themselves needing a good night’s sleep in a less-than-perfect anchorage.
In extreme conditions, the working anchor must not only have good holding power, but set quickly and perform well in a variety of bottom conditions. Most anchor makers will specify a size and weight according to the boat’s size, but these tend to be optimistic. For serious voyaging, the right size working anchor is generally the biggest one that your boat, equipment, and crew can comfortably handle. At the very least, you should move up one size from what the manufacturer recommends.
Practical Sailor’s most recent anchor tests (both in soft mud) were of new anchors in the January 2007 issue and adjustable anchors in the October 2006 issue. These anchors were primarily aimed at boats 40 feet and under. To compare the performance of heavy-weight anchors designed for bigger cruising boats, Practical Sailor turned to regular contributors and cruising veterans Evans Starzinger and Beth Leonard, who both have 85,000-plus bluewater miles—and plenty of experience with poor holding ground—under their belts.
Ashore and aboard their 47-foot Van de Stadt-designed sloop, Hawk, the pair spent several weeks testing three beefy, high-end anchors: the Rocna, the Manson Supreme, and the Manson Ray.
One of a cruising anchor’s most important traits is its ability to set easily (and reset after a wind shift) in the widest possible variety of bottoms. For those who can carry extra-large anchors, holding power, the normal parameter measured by anchor tests, is not as important as setting performance. Once set, an oversized anchor should easily have sufficient holding power.
With that in mind, this comparison focuses not on ultimate holding power but the ability of the anchors to set quickly—even in difficult bottoms and with short scope—and to stay set when conditions change. (See "How We Tested," above.)
The evaluation was divided into two parts: beach testing and real-world comparisons in a wide range of holding grounds. This article focuses only on the beach tests, with the final long-term report coming next month in the December 2008 issue.
What We Tested
The field was limited to fixed-shank Bruce-style (claw) and roll-bar anchors from two manufacturers, Rocna Anchors and Manson Anchors. The size was specified at 110 pounds, enough heft to give Leonard and Starzinger plenty of confidence when trying to secure the 30,000-pound displacement hull in the challenging holding grounds of southern Chile.
From Manson, Practical Sailor tested the plow-style Manson Supreme and the Bruce-inspired Manson Ray. Manson makes all of its anchors out of fabricated, high-tensile steel at its New Zealand facilities. The anchors are Lloyds Register of Shipping approved.
Similar to the Rocna, the Supreme was designed to be fast-
setting and have a high holding power. Users can attach the rode either to a single hole at the end of the shank, or to a slot running its full length. The slot is meant to make it easier to back the anchor out of rock and coral seabeds. This test featured the 121-pound galvanized Supreme, but it’s also available in stainless, and comes in a range of weights starting at 5 pounds. Manson recommends the 60-pound Supreme for a boat the size of Hawk.
The Ray is designed as a quick-set anchor—Manson claims it will set in only the length of the anchor itself—for use in sand and mud. It closely resembles the original, highly regarded Bruce, a cast anchor made in Scotland that is no longer available. Although Manson says the Ray "is not ideal for rock," past experience and testing bear out that Bruce-style anchors are quite versatile and can perform as well as other designs in rocky bottoms.
The Ray is available in galvanized and stainless. The galvanized Ray is fabricated, not cast, allowing for more exact measurements and consistent steel quality, according to Manson. The stainless Ray is made with 316L stainless-steel plate. For a boat Hawk’s size, Manson recommended a 55-pound Ray; Practical Sailor tested the 110-pounder.
Rocna Anchors manufactures its anchors in Canada and New Zealand and distributes them worldwide. The hot-dip galvanized Rocna, designed by Kiwi boatbuilder and cruiser Peter Smith, is touted as a fast-setting anchor. The company claims it will typically set within 3 feet.
It has all-steel construction with high-tensile steel in the shank and a small slot for attaching the rode. A stainless version of the anchor will be out this year.
The Rocna comes in a range of weights, starting at 9 pounds. The 28-pound Rocna fared well in our 2006 test ("Soft Mud Anchors $200 and Up," April 2006). Rocna recommends about an 88-pound anchor for our test boat. The 121-pound Rocna Practical Sailor tested is rated for a 52- to 85-foot boat, depending on displacement.
One drawback to roll-bar anchors like the Supreme and Rocna is that they can be a challenge to stow. On some bow rollers, they simply will not fit. On Hawk’s twin bow roller, the roll-bar anchors prevented the use of the adjacent roller, even for simply running an extra line. Stowing them in a hatch or inside the boat can also prove difficult.
Physical measurements of anchors cannot produce definitive conclusions about anchor performance, but they offer clues to likely performance in different conditions.
Our analysis found that the measurements (tip weight, total weight, blade area, etc.) of the tested anchors suggest that the Rocna and Manson Supreme should provide similar holding power when fully buried in a good bottom. (See Value Guide.)
The Ray could have an edge in setting performance and in holding power in a common type of poor bottom (thin sand over rock/coral). One note of caution is that these measurements apply only to these particular size anchors, and scale effects may change the rank order in smaller anchors.
An anchor’s tip weight is the percent of the anchor’s total weight that the tip of the anchor puts on the sea bottom when the anchor is lying on its side. (The position the anchor normally assumes when it lands on the bottom.) This is viewed as an important factor in determining an anchor’s setting ability. The Ray has the heaviest tip weight of the three anchors tested.
Blade area is the surface area of the anchor blade when the anchor is completely dug in. This is considered an important factor in determining an anchor’s holding power. The Rocna has the largest total blade area of those anchors tested.
Tip blade area is the surface area of the first 9 inches of the blade tip. A common poor-holding bottom type has a couple inches of sand or mud over a harder rock or coral surface. According to Starzinger and Leonard, it’s been their experience that only the first 9 inches or so of the tip will bury in these bottoms—and often only two of the three flukes in a Bruce design—so this measurement is an indication of holding power in this sort of poor anchoring bottom. Of those tested, the Ray has the largest blade area.
Beach Test Findings
All of the anchors Practical Sailor tested are large and of well-regarded design. Previous tests of these anchors conducted by other parties showed that all three will set easily and hold well in good sand or mud bottoms. Practical Sailor wanted to find out how they would perform in more difficult bottom conditions.
In their many years of cruising, Starzinger and Leonard estimate that 70 to 80 percent of the anchorages where they dropped the hook had good bottoms with deep sand or mud, and the remainder posed an anchor-setting or holding challenge (rock, coral, kelp, or too small/crowded/deep for proper scope). Most sailors will encounter these extreme conditions less frequently.
Given how bad the holding conditions were during the Practical Sailor rocky-bottom, long-scope, anchor-setting test (see "How We Tested," page 35), expected the anchors to have difficulty setting and holding. However, all three performed quite well, setting within 11 to 13 feet and holding 1,000 pounds of load.
The Ray penetrated the rock and started digging into the sand in half the distance of the Rocna and the Supreme: The Ray dug in at 11.7 inches, while the Supreme and Rocna dug in at 31.2 inches and 35.1 inches, respectively. This is consistent with the assumptions made by analyzing the tip-weight measurements.
The Ray also took slightly less distance than the others to set and hold the 1,000-pound load, but the differences were not significant. The Ray did not roll upright, and thus only dug in one side fluke and half the main fluke, but it dug in the deepest and held the 1,000-pound load. The Rocna dug the biggest furrow.
All three of the anchors would have dug in deeper with a greater pulling force, and the holding power of all would easily have exceeded the pulling power of the windlass used in testing (3,500 pounds). A greater load would have rolled the Ray upright. Our short-scope testing (see photo, page 39) also shows that a more upward rode angle will roll the Ray upright.
Testers tried pulling several lighter anchors—an 88-pound Manson Supreme copy, 55- and 45-pound Deltas, and a 45-pound CQR—on this beach, and none dug in. They just skated over the rocks and frozen sand. This reinforced the importance of weight in challenging bottom conditions.
The roll-bar anchors Practical Sailor tested seemed to have difficulty where there were decent size loose rocks over a hard impenetrable rock/coral surface. This was apparent in the first meter of the beach test where the roll-bar anchors hopped among the rocks before the tips managed to penetrate the frozen sand.
The Ray tends to scoop the loose rocks between two of its flukes, pile them up, and then snag a bigger rock. The Rocna and Supreme blade points will skate between the loose rocks, throwing them off to either side, until the anchor can jam on a big rock.
In small, crowded, or deep anchorages, sailors occasionally have to anchor with shorter scope than they would prefer. In these situations, Leonard and Starzinger have used as little as 2:1 scope. To simulate this extreme for the evaluation, we held a second pull test, this time on a different beach with a much-better-holding gravel and mud, using a 2:1 scope, with and without chain, and with a more upward pulling angle. We were surprised by the results.
Given the loose bottom conditions, we expected all the anchors to dig in easily and quickly. However, in the first pull, with only rope rode and no chain, only the Ray dug in. The Rocna and Supreme skated along the surface. The Rocna did dig a deeper trench than the Supreme, but neither showed any inclination to set.
In the second short-scope pull, we added 6 feet of chain to the rode. The Ray dug in almost immediately, as we had expected, but the Supreme took 6 feet to dig in, and the Rocna continued to drag. We repeated the Rocna pull three times, and it refused to bite each time.
Steve Bambury of Rocna Anchors said these results are not consistent with their experience and the results of other independent tests. He added that these have earned a solid reputation among experienced cruisers such as yacht designer and past Practical Sailor contributor Steve Dashew.
If anchoring with short scope is unavoidable, Rocna recommends, using 3:1 scope to allow the anchor to dig in, then shorten scope as needed once the anchor has properly set.
We can conclude two things from this 2:1 scope test. First, sufficient scope and chain are critical to getting an anchor to set and hold. If you have to set with short scope, it’s best to do so very slowly and gently to give the anchor tip an opportunity to angle down into the bottom. Second, the Ray performs much better in short-scope conditions than either of the two roll-bar anchors, and produced a set that would have been adequate for anything less than gale conditions.
The Ray, Rocna, and Supreme are all well-made anchors, and all showed good setting ability in difficult bottom conditions in our beach testing. The performances of the Rocna and Supreme were very similar, with the edge going to the Supreme in price and short-scope situations and the Rocna in hard sand and ultimate holding.
The Ray design offers faster and deeper setting in a variety of bad bottom conditions but, based on data from other sources, it has a lower maximum holding power. The Ray does make an excellent general-purpose anchor for serious cruisers likely to encounter such challenging conditions regularly; be sure to select a size that is one or two sizes larger than the equivalent roll-bar anchor. (Note: Based on experience and anecdotal evidence they’ve collected, Leonard and Starzinger believe that Bruce-style anchors’ effectiveness—relative to other styles—may be diminished in sizes under 44 pounds.)
The Ray is quite expensive compared to other Bruce copies, but it is noteworthy as its forged shank construction would have prevented the casting cracks that destroyed Starzinger and Leonard’s previous 50-kilogram original Bruce.
Based on the measurements and beach testing, our initial—and tentative—recommendations are that the Practical Sailor Best Choice for difficult conditions (bad bottom/short scope) is the Manson Ray. The Supreme gets the Budget Buy nod as its performance was very close to the Rocna, but it is significantly less expensive.
For many, it will come down to stowage—which one will fit your bow roller or locker? In truth, you can’t go wrong with any of these big boys. While the Rocna and Manson Supreme’s short-scope setting ability fell short of the Ray, both have a hard-earned reputation in the field.
Practical Sailor encourages readers to weigh these results along with those of previous tests on more typical bottoms before selecting a primary anchor.