penetration
In order to hold, an anchor must first deeply penetrate and set in the various types of seafloors. There are two types of setting: static and dynamic.Static SettingAlmost always followed by dynamic setting, this setting is typical for cargo ships, where the anchor, from several hundred pounds to several tons, sinks into the seafloor from its sheer weight alone. No extensive research has been carried out regarding effective setting for these circumstances.In terms of small craft navigation, we can find a similar static setting with the plow anchor, which they don’t manufacture under 15 pounds, simply because anything lighter could not function. Anchors which are not sufficiently heavy may only offer cursory holding in more compact or weedy seafloors, but they might be very effective in soft mud.Dynamic SettingThe traction of the rode ought to force the anchor to pierce and bury in the seafloor. Although its own weight may facilitate static setting, lightweight anchors will also set; it suffices that the anchor tip encounters a sand ripple, or a soft area to pierce, followed by the backward traction force which drives the the anchor into the seafloor, caused by the engine in reverse.On compact or weedy seafloors, some anchor models tend to skim the seafloor for some distance before taking hold.To ensure a speedy setting in virtually all types of seafloors, there are a couple of physical characteristics to consider:Regardless of the tool, depending on the substance, two parameters ensure good setting:-The proper setting angle and -The highest amount of pressure possible.The optimal setting angle adapted for anchoring is the “chisel angle.”The Fortress anchor features a "Razor Blade Angle":This angle, superior to 150°, is typical of plate or articulating anchors. They necessitate contact with a sand ripple or soft area for their fluketips to pierce the seafloor surface; they then assume the chisel angle and set. On compact or weedy seafloors, these anchors shave the bottom without taking hold. Setting Pressure:Pressure is defined as force divided by surface area. Here, we have two variables: force (daN) and surface area (mm²). The force must be as high as possible and the surface as small as possible to maximize the pressure. A number of anchors have sharpened setting edges, as do the Fortress, FOB THP, the Bügel or the Spade. The distribution of weight in the fluke tip makes sense in anchor design as it facilitates setting. We can see a great disparity amongst fluke ballasting in various anchors: The fluketips of flat anchors and the CQR comprise between 12 and 16 % of the total weight of the anchor, while the ballasted tip of the Delta contains 28% of its total weight. The SPADE anchor contains 47% of its total weight in its point. We can see that an anchor will tend to set more easily in the seafloor when it launches with the appropriate penetration angle coupled with the maximum pressure on its fluke tip.(From the book: " The complete anchoring handbook"..)