Independent testing

From the Rocna Knowledge Base
Jump to: navigation, search
PeterSmith-icon.png The topic of this section is supplemented by an article at the Rocna designer's personal website.

To read this article, click here: Independent Anchor Performance Testing

Independent anchor comparison testing forms one of the few credible sources of information for the boater looking for the ideal anchor. Unfortunately much (most?) magazine "testing" is severely lacking in its methodology and results analysis, rendering it scientifically invalid. Testing anchors involves many different variables, and there is debate about what results an experiment should be testing for. This gives anchor testing a bit of a bad reputation.

This section is a collection of testing material and results. It includes only tests which have included the Rocna (which rules out anything before 2004), and is restricted to truly independent (that excludes anything with connections to an anchor manufacturer, including our own testing) and well controlled tests.

West Marine 2006 (SAIL / Yachting Monthly)

West Marine 2006 testing

In 2006, West Marine conducted a major series of anchor testing in California on sand seabeds. Their testing involved 14 anchor types in the 15 kg / 35 lb size range, three different real world underwater locations (with varying bottom types), and a real world rode connecting the anchors to the test boat.

In their 2007 and 2008 catalogs, they published a brief summary of this testing, including some very brief summary comments relating to each anchor. These are quoted in the table below, together with the details of each anchor tested.


Sizes and types

The anchors chosen were as above in the small to mid-sized range, around 15 kg / 35 lb. An unfortunately common mistake was made by the inclusion of varying materials, i.e. mixing aluminium with steel anchors, with the Fortress and the Hydrobubble. The aluminium Fortress FX-37 tested is massive, and would weigh over 25 kg / 55 lb if it were built from steel. This is not to say that aluminium anchors are inherently more efficient – steel is used by most anchor types for reasons relating to durability and strength. Indeed, the Fortress was damaged during the testing! The two material types are not easily comparable, as they have different purposes and applications.

There was a significant variation in sizing with some of the other anchors also. Below, the results are shown in both their raw form, and scaled on a size-for-size basis.

The rode used was 1" (25mm) nylon rope with a 20' (6m) leader of 5/16" (8mm) chain, deployed at three different scopes of 3:1, 5:1, and 7:1. Anchors were pulled from a powerful motorboat capable of pulling all anchors to the force cap of 5,000 lb (2,270 kgf).

Locations and seabeds

Three locations with varying types of seabeds were chosen. This is fortunate and is an element missing from much testing. While an anchor might perform well in one or two pulls at a particular location, its consistency and reliability is not tested at all unless the same test is repeated at other locations. Some of the contenders did manage to record high pulls at least once or twice, but their average results are greatly damaged by failures to perform at other locations.

All seabed types were sand, generally firm and hard. This is one of the reasons that some of the old generation anchors could not be made to set reliably, and this makes a good testbed from which a harsh light is shone on those anchors which are not good all round types. Versatility is closely examined in this test.

Summary comments

Company Anchor Material Weight (lb) Comments verbatim from West Marine
Noteco Bulwagga 27 Steel 28.6 Held up to 3,000lb., engaged each attempt. Released and failed to reset at higher loads.
Lewmar Claw 33 Steel 36.3 Failed to set during this test. Maximum tension under 700lb., briefly.
Lewmar CQR 35 Steel 38.5 One promising set to 2,000lb., but little else. Would not engage bottom.
Lewmar Delta 35 Steel 36 Variable results ranging from around 1,500lb. to 4,500lb. Drags at limit.
NavX Corp Fortress FX-37 Aluminium 21.9 Generally held as much tension as we could throw at it. Was slightly damaged when pulled over 5,000lb. Excellent performance.
Anchor Concepts Hydrobubble 45 SA Alu & stainless steel 16 Surprise performer based on small size and weight. Held over 5,000lb. twice, also held to 1,600lb twice and released.
Manson Marine Manson Supreme 35 Stainless steel 35.9 In six pulls never held less than 2,300lb, and held over 5,000lb three times. Seemed to engage the bottom immediately.
SPADE Océane 35 Steel 38.2 Highly variable results. After four disappointing results, the Océane held over 5,000lb on the last two pulls. Puzzling.
Rocna Anchors Rocna 15 Steel 32 Superb, consistent performance. Held a minimum of 4,500lb and engaged immediately.
Anchor Right SARCA #5 Steel 33 Medium performer that held in the 2,000lb range and either released or dragged. One pull to 5,000lb.
SPADE Spade S80 Steel & lead 34.4 Somewhat mixed results with three OK pulls, and three maximum pulls. Set immediately each time.
WASI WASI 35 SS Stainless steel 32 Varied results from 1,300lb to maximum tension. Failure mode was generally dragging.
West Marine West Marine Performance 20 Steel 26.3 Disappointing results considering previous tests. Held 200 to 1,500lb, but could not get a secure grip.
XYZ Marine XYZ Stainless steel 10.6 Could not get anchor to work. One pull at 900lb, but mostly dragged on the bottom.

Pull results

Below is a chart as published by SAIL magazine which shows for all 14 anchors three averaged measures, being "max before releasing", "stable dragging", and "max pull".

  • Max before releasing is the average force the anchor held before dragging (in other words, holding power). It is the more important of the three.
  • Stable dragging is recorded if the anchor failed to set and attain a reasonable resistance.
  • Max pull is the average of peak forces recorded for the anchor. This figure should be higher than "max before releasing", as it occurs once the anchor has been pulled beyond yield. Its absence is a tell-tale sign of poor behavior and means that the anchor released completely rather than remaining embedded once it started to drag. Ideally this figure should be close to "Max before releasing", indicating both high resistance to yield and stable yield behavior.

Averaged raw holding power


Commercial involvement of West Marine

This testing has been criticized by proponents of the anchors which tested poorly who allege that West Marine, who after all do sell anchors, are not a neutral party. However, this criticism rather ignores the results. By publishing these results, West Marine did far more harm than good to these interests, as their primary line-up of anchors at the time were the Lewmar range of the CQR, Claw, and Delta, and the Manson Supreme, not to mention its own branded Danforth type – all of which did not fare particularly well. In actual fact, it could be argued that some bias was displayed toward these anchors, particularly the CQR, which enjoyed far more attention than the others when it refused to set. The #1 performer, the Rocna, was not sold by West Marine at the time of testing.

Magazine publication

SAIL and Yachting Monthly magazines sent reporters to attend the West Marine testing, and later published write-ups on it. Similar articles appeared in respective sister publications. Unfortunately both publications published differing results, making contradictory comments about each anchor. The editorial of both magazines often strays from the narrative of West Marine themselves. SAIL was the sole magazine to publish averaged holding power along with peak pull loads, and this tallies well with the summary analysis published by West Marine, as above.