## 3 Materials and Methods
### Procedure  
The testing sequence is depicted in Figure 15.  
A hand-held scale with a max weight indicator was checked for calibration and used to measure anchoring strength. During each pull, the wire root array was carefully inserted into the sediment and the root ring was depressed until it fully compressed the acrylic spacer onto the anchor plug resting on the sediment. Care was taken not to allow the plug itself to depress more than approximately 1 cm into the sediment or the wire roots to jam, tangle or otherwise fail to insert through the root tunnels in the anchor plug. The spike was then inserted through the wire root ring and anchor plug and carefully screwed into the sediment until firmly compressed against the upper spacer. The scale hook was then inserted through the thumb ring at the top of the plastic anchor spike, and the handle was smoothly pulled upward for the vertical tests, or at an approximately 45-degree angle for the angled tests, until the anchor released from the sediment. The angle was kept consistent for the angled pulls by keeping the scale handle just above the upper lip of the bucket during the pull, set to equal heights in all three sediment conditions, with the anchor rooted  
Figure 14: Sediment Samples: (**a**) Condition 1: Clay and pebble mixture; (**b**) Condition 2: Fine silt; (**c**) Condition 3: Beach sand.  
Figure 15: Testing sequence: (**a**) Wire root array ready for inject; (**b**) Anchor assembly fully rooted; (**c**) Vertical pull test completed.  
to the same depth and the scale attached at the same point (the thumb ring of the anchor spike). Care was taken to pull steadily without jerking the anchor free. The force was smoothly yet reasonably swiftly applied over a relatively short time period (approximately 1-2 s)--not as a jerk. The objective was to produce a consistent, steady pull through failure. We believe a jerk would give an unduly high strength measurement for the pulls. It is, however, worth noting that it is likely that in real-world scenarios, jerk force applications could influence anchoring strength. Such scenarios could reasonably be expected in shallow litterals affected by wave action, for example. Jerk force testing was outside the scope of testing for this early prototype analysis. Following the pull, the max tension (in pounds) was recorded. To prepare for the next pull, sediment was removed from the assembly, and a wooden block was used to firmly re-compact the sediment. The bucket was then rotated slightly so as to avoid using the exact same spot for the subsequent pull and help ensure the independence of the data.  
Test 1 consisted of a sample of 30 straight (vertical) pulls using the full array of eight wire roots within the anchor plug and the spike fully inserted in each of the three sediments, for a total of 90 pulls. Test 2 was conducted in a similar manner, with the exception of the reduction in the total number of wire roots within the array to four, evenly spaced, again for a total of 90 pulls. Test 3 consisted of the same procedure, but with the anchor spike alone, inserted to the same depth as in all the other tests, once again for 90 pulls. Test 4 consisted of ten pulls in each of the three sediment types using the full wire root array (eight wires) but this time pulling at an angle of approximately 45 degrees, for a total of 30 pulls. Test 5 was conducted in the same manner as Test 4 but without the wire root array (anchor spike only), again for a total of 30 pulls.