Practical Sailor’s Heavyweight Anchors Test 2008
Manson Anchors and Rocna hooks face real-world testing in a range of difficult conditions in Southern Chile—from kelp-filled anchorages to glacier-carved rock-bottom coves.
In a followup to the November 2008 shoreside testing of three large cruising anchors, this field report offers a glimpse of how the Manson Supreme, Manson Ray, and Rocna anchors perform in the real world. The test products, two roll-bar anchors (Rocna and Supreme) and one Bruce-style anchor (the Ray), are all acceptable as main cruising anchors. They are all good, but with distinctive strengths and weaknesses, so we tried them out, anchoring in dense kelp, soft mud, and hard rock bottoms, as well as in anchorages where short scope was required.
A cruising boat’s working anchor must not only have good holding power, but it should set quickly and perform well in a variety of bottoms.
The November issue introduced three large, well-made cruising anchors—the Manson Ray, Manson Supreme, and Rocna—which we tested with an emphasis on their effectiveness in difficult bottom conditions. Weighing the test performances and measurement analyses, testers gave the Ray the thumbs-up for setting quickly and holding in a variety of bad bottom conditions (rocky and short scope).
The second phase of testing these heavyweight anchors for larger boats was actually putting them to use—and abuse—on a cruising boat in the "real world" conditions of the Chilean channels. Practical Sailor contributors and cruising veterans Evans Starzinger and Beth Leonard commissioned the anchors for service during their three-season, anchorage-hopping cruise of Southern Chile aboard their 47-foot aluminum Van de Stadt-
designed sloop, Hawk.
What We Tested
For this round of anchor tests, we limited the field 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, heavy enough to give Leonard and Starzinger confidence in securing their 30,000-pound displacement hull in less-than-ideal anchoring 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.
Starzinger and Leonard tested Manson’s plow-style Supreme and the Bruce-inspired Ray. Both carry Lloyds Register approval. Similar to the Rocna, the Supreme was designed to be fast-setting and have a high holding power. It has two rode attachment points: a single hole at the end of the shank and a slot running its full length. (The slot is meant to make it easier to back the anchor out of rock and coral seabeds.) We tested the 121-pound galvanized Supreme; it also comes in stainless.
The Ray also is designed as a quick-set anchor, but for use in sand and mud. It closely resembles the original, highly regarded Bruce, a high-quality cast anchor that is no longer available. The Ray is available in galvanized and 316L stainless-steel plate.
Rocna Anchors’ hot-dip galvanized Rocna 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. The 28-pound Rocna fared well in our 2006 test ("Soft Mud Anchors $200 and Up," April 2006), and we tested the 121-pound Rocna in this test.
How We Tested
The Rocna, Manson Supreme, and Manson Ray are all good anchors and all will set and hold well under normal anchoring circumstances. But, as with the shoreline tests reported in the November issue, we wanted to put the anchors to use in difficult bottoms to determine the best large working anchor for a variety of poor anchoring conditions.
During their cruise of Chile, testers Starzinger and Leonard set out specifically looking for difficult or unusual anchorages. The holding ground there was typically good mud, but they did find several coves rated only Fair or Poor holding in the local cruising guide. And those were the venues for this real-world anchoring test.
It is impossible for these real-world tests to be as "scientific" as bench tests or the shoreline tests conducted for the November issue. You cannot ensure consistency or repeatability in real anchorages, and murky water makes it impossible to clearly determine what has gone wrong.
The conclusions drawn from this testing are by no means definitive. They are meant to supplement our recent shoreside tests as well as other parties’ holding power tests.
The testers anchored Hawk in 15 different coves using the test anchors. In eight of those, they had no problem with the anchors’ setting or holding. In the other seven, however, they encountered some difficulty and made notes on the results.
The test site anchorages were classified according to bottom type: soft mud, dense kelp, and rock bottom. Two of the coves were particularly small and required testers to use shortened scope. It is important to note that these conditions are not considered typical. Practical Sailor encourages readers to weigh the following findings along with those of previous tests on more typical bottoms before selecting an anchor.
Soft Mud Bottom
One test site had very soft mud. None of the locals would anchor or even set a mooring in this area because the holding was so poor.
When testers dropped the anchors in the ooze and started pulling immediately on the rode, they found the Manson Supreme set the quickest. (We suspect that because it was the heaviest, it settled into the harder mud fastest.) The Rocna was a close second, and the Ray just pulled through. However, testers found that if they did not pull immediately on the Ray, let it settle on the bottom for a while, and then pulled gently, it would set and hold.
The anchors were tested in one anchorage plagued by very dense kelp. A kelp knife is essential cruising equipment in the Chilean channels—exactly for anchorages like this—as each time you pull an anchor up, you also pull up several hundred pounds of kelp that has to be cut away.
This was the most difficult bottom in which to attempt a repeatable and well-controlled test because it was impossible to drop each anchor into exactly the same amount of kelp. However, the Ray was most consistent (likely because of its high tip weight), the Rocna a distant second (probably because of its sharp tip), and the Supreme a close third.
All the anchors preferred a slow settle and set, rather than a fast yank, in this bottom.
Two test sites had glacier-carved rock bottoms. The Ray did quite well, quickly snagging something each time it was dropped. Testers note that swinging-to on this bottom likely would pull the anchor unstuck. However, it was just fine for the stern-tying approach used in these coves.
The Rocna and Supreme performed identically: As they came under load, the anchors would snag, then let go, snag, let go. It seemed their tips were pulling around or over the rocky bottom. They never set.
Short Scope Required
Two other test anchorages were very small. Normally in Chile, Starzinger and Leonard would stern tie to shore in this type of cove, but for this test, they tried anchoring with short scope: 2:1.
The Ray set each time. The Manson was right on its heels, requiring a few tries, and the Rocna was third, setting only after more scope was eased out for the initial set and then shortened up. In one cove, the bottom sloped quite steeply away from the anchor pull, which mechanically is similar to short scoping. The roll-bar anchors failed and pulled away in just under 15 to 20 knots of wind as the testers attempted to sort out the dinghy and lines for a stern shore tie. The Ray, at least, held long enough to get a stern line ashore.
Practical Sailor would consider any of these anchors acceptable as a main cruising anchor. They are all good, but with distinctive strengths and weaknesses. The Ray offers the best all-around setting ability in poor bottoms, but—according to other anchor tests—it has the lowest holding power per pound. If you plan to use the Ray as a main anchor, get a big one.
The Rocna and Supreme have much higher holding power per pound but are less reliable setting in very difficult bottom conditions and may take a bit of additional skill and scope to get set in these unusual sort of conditions. And ultimately, if an anchor won’t set in a certain bottom, it’s holding power is irrelevant.
Which anchor is best for you will depend on what sort of difficult bottoms you are most likely to encounter and the trade-offs you make between setting reliability in difficult bottoms versus weight/holding power in more normal bottoms.
Practical Sailor was somewhat disappointed in the Rocna and the Supreme’s performances as our expectations were very high based on their marketing and the results of other people’s anchor tests, and we feel they didn’t live up to the hype. These field tests demonstrated to us why we have had such good success with big Bruce designs in the past.
Testers don’t yet have a complete understanding of the Rocna’s strengths and weaknesses, so for the meantime, the low-profile roll-bar anchor will remain in the long-term testing lineup. The higher-profile Supreme, however, awkwardly fits Hawk’s bow roller but not the stowage lockers and so didn’t make the cut. (Neither roll-bar anchor is likely to work on boats with deck-mounted bow sprits.)
Starzinger and Leonard will put the big Ray and Rocna through more long-term testing as they cruise South Georgia. Look for updates.