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Selection of Anchorage. The tests indicate that because no anchor performed well in rocky, kelp-infested areas, a selection of suitability of bottom for anchoring, may be more important than selection of an anchor. Indications on nautical charts of bottom characteristics are very general. Cook and Vancouver took the time to investigate potential anchorages but in these days of electronic gadgets it is probably unrealistic to expect yachtsman to use tallow on a lead line. Investigation of holding ground is possible through experience and, if all else fails, experimentation. Since it is generally difficult to verify the quality of the set, the best insurance is personal experience with a given anchor design and its suitability for specific bottom conditions. Selection of Anchors. There would appear to be at least four important criteria for anchor selection: (1) reliability to set, (2) holding power, (3) ability to withstand veering, and (4) susceptibility to damage. The Luke and Davis anchors failed to either set or hold so consistently that they can be considered unacceptable. Importance of High Percentage of
Setting. This is a very
important factor in all but windy conditions and in this regard the Bruce would rank the highest. This is probably why many
Bruce
anchor owners express satisfaction with its properties. The
setting percentage in our tests were.
The results are skewed in favor of the anchors which set in foul ground. However, those areas should not be selected for anchoring in all but the lightest weather, e.g., day anchorages and calm. Impact of Veering Tests. The veering tests were 56 in number and primarily conducted at one site, which was good holding ground. In general, the unstable anchors were unstable on veering and the good holding anchors held well on veering.14 Holding Power. The worst time for an anchor to drag is in extreme conditions. Those situations often occur at night, on lee shores or when a vessel may be surrounded by coral heads, reefs or other boats. Most cruising boats in Puget Sound may anchor thousands of times in summer weather yet never experience a storm anchorage. However, the probabilities of foul weather increase if a boat cruises to the West Coast of Vancouver Island, further north, or in the winter months. For argument, two thresholds could be established for a 45' sloop (1) 42 knots (rare indeed in an anchorage), (2) 63 knots (the edge of the hurricane and perhaps a once in a lifetime event). 42 knots. Strain of 844 lbs. according to Smith tables; for safety factor, deck houses and or ketch rigs raise this to 1,000 lbs. Assessment is made on the minimum capability of the anchors to achieve 1,000 lbs. holding power, in the Puget Sound tests the anchors. 63 knots. Strain of 1899 lbs.; for safety factor, deck houses and/or ketch rigs raise to 2300 lbs. The ABYC tables state that a 45' boat with 13' of beam should have a storm anchor capability of 3,200 lbs. For our purposes four anchors demonstrated the capability of more than 2,300 lbs. holding power one or more times during our testing sequence. Damage. The MAX and Fortress anchors both sustained significant damage. The MAX bent its flukes twice and shank once (seriously). The Fortress bent both flukes on one test and the shank twice. However, most damage was sustained at strains in excess of 3,000 lbs. which was probably more tension than would be generated by a sailboat of less than 56 feet in winds of 63 knots. Boats that size should have bigger anchors. The Performance 35 sustained no damage although it sustained loads of 4,100 lbs. The Fortress did bend flukes at 2,100 lbs. on primarily sand bottom at Blake Island. The first thing the tests indicate is that the Puget Sound areas tested do not compare exactly with the Columbia River, San Francisco or Florida tests. Just as the holding power of mud varies, so does the holding power of sand. In the end it is an analysis in soil cohesion; just as a civil engineer would analyze soils for construction of a pier and vary the piling length, so must power of the anchor depend on the particular soil. Nevertheless, there are similarities in how the holding power of the anchors ranked. A comparison of the San Francisco mud tests, the Smith observations and Puget Sound tests would rank the similar anchors as follows for holding power:
In the Puget Sound tests the Performance 35 had only slightly less holding than the FX 37. It was not tested in San Francisco but would be more comparable to the Danforth Hi Tensile 33. The Bruce demonstrated the least holding power and the CQR about mid to low range in all three areas. The Delta was marginally better than the CQR in San Francisco and Columbia River, but the reverse was true in Puget Sound. Adequate holding power should be the most important criteria rather than the ease of setting. An average sailboat auxiliary engine of 30-40 H.P. can exert perhaps 300-400 lbs. backing down while setting an anchor. Many anchors would hold at that tension, giving the illusion that the vessel is secure, only to fail when the wind builds. In our tests the Bruce had a tendency to reset after a drag then it would drag again only to reset. If a person had been below during dragging, the dragging might not be observed. It would seem preferable for an anchor to not set than to set and hold at only moderate conditions. For Puget Sound conditions we would therefore rank the anchors as follows: 1. Performance 35 or similar pivoting fluke steel Danforth style. Ample holding power, construction resistant to damage. Adequate setting characteristics. 2. CQR 45 - Although significantly less holding power than the Danforth types, it is resistant to damage, has enough holding power for most conditions, and is relatively easy to set. 3. Fortress 37 - When set has more holding power than any of other anchors tested. Harder to set than most anchors and subject to damage. 4. MAX 17 - Very good holding power in most areas but subject to damage at higher loads.17 This anchor did not hold well at Blake Island. 5. Delta 35 - Not easy to set and not a storm anchor for Puget Sound. 6. Bruce 44 - Easy to set and strong but must be ranked as a moderate weather anchor for Puget Sound. 7. Luke 50 - Consistently failed to show even minimum requirements for holding. 8. Davis 45 - Consistently failed to set at all.18 The foregoing recommendations are made on the basis of the tests observed and review of other tests. It is recognized that there is anecdotal evidence that some of the lower ranked anchors will occasionally perform better than indicated. For example, see Practical Sailor August 15, 1994, describing an incident where a CQR failed and a MAX held in severe conditions.19 Or, see the report of Bloodhound anchoring on a rocky lee shore in a storm with a fisherman style anchor. Heavy Weather Sailing, Coles (1956). However, the anecdotal reports are subject to imprecision and soils differing from those observed during our tests. We acknowledge the help of Bob Smith in preparing this report and the comments of Andy Peabody of Creative Marine and Chuck Hawley of West Marine. Wilbur Andrews and Bob Taylor provided comments on the test procedure when the test plan was designed August 1, 1995 |
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