Here is some data from some of my testing a "Sandy Mud" seabed in
Washington State (note: The original poster of this discussion described the seabed of his dragging event as "Sandy Mud").
In these tests, I chose to measure the maximum resistance during a pull with an electric
winch. In all cases the anchors were moving when developing peak values. The fact that winching "speed" slows as load increases means that the larger anchors are (generally) moving slower than the smaller anchors. It is not clear to me what effect this has, but, it may account (in part) for the larger anchors having higher efficiencies than the smaller anchors.
All tests were conducted with the same rode: 12' of 5/16" chain +
Dyneema rope. The fact that smaller anchors will have MORE difficulty burying this chain than the larger anchors may account (in part) for the larger anchors having higher efficiencies than the smaller anchors.
I believe that this amount of chain (12') is small enough, and the loads high enough, that measurable catenary will be eliminated.
The data was derived by dividing the Peak resistance by the weight of the anchor.
---------------10kg (range)------------20kg (range)
Spade (steel)------75----------------------107
Vulcan--------------67---------------------109
Mantus M2---------67-----------------------95
Quickset------------55-----------------------88
Viking---------------52---------------------104
Excel----------------51----------------------87
CQR-----------------50----------------------72
Mantus M1----------43----------------------78
Delta----------------41----------------------41
Rocna---------------27----------------------15
Bruce---------------15-----------------------16
Average------------49.4--------------------73.8
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The next set of data is from my testing in a "Cobblestone" seabed in
Washington State. In these tests, a true maximum HOLDING was measured (anchor not moving) using the
propeller thrust of a test vessel.
All tests were conducted using all chain rodes with enough scope to ensure that the chains did NOT
lift at the anchor. In other words, the angle of pull on all anchors = zero.
Because all anchors used similar chains (that were laying on the seafloor), the small anchors likely have an advantage due having a higher percent of their holding power coming form the friction of the chain on the seafloor.
The data was derived by dividing the holding power by the weight of the anchor:
---------------10 kg (range)----- 20 kg (range)
Excel----------------8.9--------------8.6
Rocna (rollbar)-----8.2--------------7.2
Mantus M2---------8.2-------------11.4
Mantus M1---------8.2--------------8.6
Vulcan--------------7.9--------------8.4
Quickset------------7.5--------------6.3
Spade (steel)-------7.1--------------8.2
Delta----------------6.9--------------4.3
Viking---------------6.7-------------16.5
Bruce----------------6.4-------------3.4
CQR-----------------5.2---------------1
Average------------7.4--------------7.6
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This next set of data should be taken with a
HUGE GRAIN OF SALT because a rode that included 80 FEET OF CHAIN was used on all of these test anchors. This means that the smaller anchors received a LARGE benefit due to the effect of greater chain catenary (lower angle of pull). Yes, the small anchors were hindered by having to drag a proportionally larger chain through the seabed, but I believe this factor is far overshadowed by the increase in chain catenary.
The test was conducted in a "Soft Mud" in Washington state (creamy organic material, no sand).
The rode was 80' of 5/16" chain + nylon at 5:1 scope.
The data was derived by dividing the peak resistance by the weight of the anchor.
------------------------10kg (range)--------------20kg (range)
Mantus M1----------------37--------------------------20
Viking---------------------32--------------------------21.5
Rocna---------------------27--------------------------18
Bruce---------------------25.5------------------------18
Vulcan--------------------22--------------------------16.8
Mantus M2---------------21--------------------------12.2
Excel---------------------20---------------------------13.7
CQR----------------------20---------------------------10.8
Spade (steel)------------19---------------------------10.3
Quickset------------------14---------------------------8.2
Delta----------------------5.6--------------------------3.6
Average-------------------22.1------------------------13.9
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The next set of data is from my testing of 5 Genuine Bruce anchors of different sizes in a "Soft Mud" seabed in Washington State.
A rode consisting of 3/8"
Dyneema (only) was used for each anchor.
The data was derived by dividing the peak resistance by the weight of the anchor.
-------------5kg----------15kg----------20kg-----------30kg-----------50kg
Bruce-------25-----------13.5----------12.7------------10.6------------15.2
-------------------------------------------------------------------------------------
Steve