pdqaltair, thanks for the complete explanation. Can you define super soft mud. Also, is the procedure for setting a Danforth different than for setting a Rocna?
Bottom firmness. The US Navy used to have a procedure the used two men in a small boat, with a hammer and a blunt stake. Though primitive, it is a simple, practical description. I sometimes use the term very soft and supper soft interchangeably. I generally use a kayak paddle; if I can push the paddle into the mud more than a foot with one hand while sitting in the kayak, it is very soft.
• Very dense sand: more than 50 blows/foot.
• Sand: 25-50 blows/foot.
• Hard clay: more than 16 blows/foot.
• Consolidated mud/clay: 4-16 blows/foot.
• Soft mud: 2 blows/foot.
• Very soft mud/silt: you don't need the hammer.
Setting pivoting fluke anchors. There are two main differences:
1. Feel. Because of the way pivoting fluke anchors must rotate into position, it really helps to start with little more than hand pressure. Of course, this is true of all anchors. Then increase the pressure very gradually until the anchor is set.
2. In soft mud the chain must be very light and you can't wait to set it. The challenge is that the chain and shank are narrow and heavy and sink in the mud, and the flukes are light and float on top. This results in the tips pointing upwards, planing along, unable to set. Keeping the shank light and setting quickly helps. However, this initial set should be very light, just enough to catch the tips. Then wait 10-30 minutes for the mud to consolidate around the anchor before giving it a good power set.
Some suggest getting the initial grab at short scope Same idea, to lift the shank and keep it from sinking. But this is only to get that critical initial grab. Then set at long scope.
Sometimes pivoting fluke anchors just won't bite. They don't like weeds, rocks, trash, gravel, or very hard bottoms. Thus, they are not the best choice as a primary anchor in most areas. They are one of the best kedge and secondary anchors, by virtue of their great power in soft mud and light weight.