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Michael wrote:
"A main, or “Working Anchor” should hold up to 30 knots of wind. A “Storm Anchor” is for winds up to 42 knots. Remember that as the wind speed doubles, the holding requirement quadruples!" Do you have a point? The above was quoted from the URL that was provided as a reference. OK, no point but you just want to review everything you've read about anchoring. That's OK, this all gets covered here every 2 or 3 weeks, it seems. .... I know more than one experienced crusier that do infact have a storm anchor...the old Hershoff style fishermans anchor that was about 70 lbs which they called their "storm achor" generally these can be taken apart and stored below. Large Fortresses are gaining favor in this regard - more bang for the buck (or pound). However, in a major storm the wind will shift, so you need more than one anchor that can handle a serious load. A friend is fond is fond of pointing to a small Danforth he keeps on the stern and saying, "That's the anchor that held us in the 'Storm of the Century.' " He now carrys a large Fortress in the bilge, but for that storm he had an array of three anchors set - the largest a 35 pound plow. All had large scope - I think the Danforth was set in a mud bank so at low tide it actually had negative scope! .... My point is that what you call a "working anchor" does not become a storm anchor simply by adding a kellet. I didnt suggest that...but that "as the wind speed doubles, the holding requirement quadruples!" as quoated from fortress anchors The kelt does 2 things effectively: 1 It acts as a snubber In light air it has similar effect. In heavy air, however, its "snubbing power" evaporates. This is not a problem if rope is included in the rode, but an all chain rode needs a proper snubber. Of course, I'm not saying not to use the kellet in heavy air, only that it shouldn't be relied on. In this case it acts as though you had slightly more (or larger) chain. 2 Keeps the chain on the bottom (when not in sorm conditions) and exponentially increases the holding power (vertical pull out) of the anchor. "Exponentially"??? I think not. In fact, it adds little if proper scope is used. Its utility is also diminished if you use a significant amount of chain on the rode. In other words, it can be very useful if you use 6 feet of chain and 3:1 scope. If you have 50 feet of chain an always use at least 5:1 scope, the utility is diminished. I havent used this tech. myself but the cantanery principle does make alot of sense to me. The "catenary principle" is often used when discussing anchors. It is nonsense, only used by those who think a mathematical sounding word is needed to explain what's going on. A catenary is the shape assumed by a chain suspended by its two ends. A suspension bridge is the classic example; a chain anchor rode is another. However, the reserve holding power of a chain is in the part that is still lying on the ground, not the part that is lifted up and is in the catenary shape. The reason is this: if a rode is assuming the catenary shape, the difference between that and fully extended (i.e. "rod-straight") is small, maybe a foot or so. The "reserve" is in the distance the boat can move when hit by a wave, not the force it takes to straighten out to chain. Thus, when someone draws the picture with the nice curve, and says "look at this catenary, that's what gives the smooth ride and holding power," it means they don't really understand what's going on. The kellet works because it forces the rode out of the catenary shape. The rode can be viewed as two parts separated by the kellet: The part nearest the anchor sees a shallow approach so it acts as if the scope were larger. The part near the boat acts as if the rode had a larger chain at the anchor end, which needs a larger force to lift it off the bottom. However, both of these affects diminish in stronger wind, as the kellet is raised and the rode straightens. Is a kelt necessary? Since I dont know of many that use one, probably not as they use other means of snubbing the anchor line, if at all. If I had the experience of using one, then I would decide if it was necessary. Thats why the original post sought others thoughts, either in principle or from usage experience. Still, i like the idea and it is something that you could probably make yourself....I like those kind of ideas.... As I said at first, handy but not necessary. They are most useful if you use minimal chain and scope. They can also be handy in reducing the tendency to swing. I used one often on my first boat, which was too small to carry all the ground tackle I wanted, and didn't have a windlass. I used one a few times to reduce horsing on my second boat, but also found I could just drop a weight to the bottom on very short short scope to accomplish the same thing - this is sometimes called a hammerlock anchor. Now I rely on a good anchor, 50 feet of chain, and a windlass, and use a second anchor for security. BTW, the friends I mentioned earlier have lived mostly at anchor for the last 25 years. They frequently deploy a kellet. They've tried a number of shapes, I think they now they use a set of diving weights strapped around the rode. I'll ask them about it the next time they pass through. (They're wintering now in Newfoundland!) FairWinds.... ... and a Following Sea |
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