There are two accessories that, if you know how and especially when to use them, can be of great help to you in anchoring in the roadstead. The salmon and the grippiale.
Salmon and grapple: how to make anchoring even safer
Salmon is a weight that is spun along the anchor line in search of increased line cushioning and improved anchor working angle. Numerical analysis of the catenary allows some basic considerations to be made:
(a ) In terms of dampening and improving chain/anchor angle, the addition of a salmon can be replicated by an increase in anchor line length, achieving virtually identical results. For example: total depth 5m, 25m of 10mm chain is lifted by applying a horizontal pull of 123kg. Adding a 15 kg weight at the middle of the chain, the force to lift the whole chain rises to 153 kg. The same 153 kg can be obtained by spinning 28 m of chain. Salmon can be useful when you want to increase the tightness but there is no possibility of increasing the length of the calumus: the anchorage “tops down,” is a classic case.
(b) If the effect on the angle of chain pull on the anchor is to be maximized, the salmon should be placed as close to the anchor as possible. Using the same example as above, by placing the 15 kg at the anchor the force required to lift the chain becomes 184 kg; the same 184 kg can be obtained by spinning a little more than 30 m of chain: salmon allows for a noticeable reduction in the length of chain required.
(c) To have any appreciable effect on the catenary, the salmon must be relatively heavy: using a weight of a few pounds on a 10-12m boat is almost irrelevant. If you plan to use it, you have to make some considerations about the practicality of carrying around a 10-20kg block.
(d) Salmon can be useful in calm conditions to reduce boat movement around the anchor; in this case, even a light salmon can be effective. At what distance to place it? Theoretically, the best effect on the angle of chain pull on the anchor is achieved by putting it attached to the anchor; since anchors tend to sink considerably into the bottom, it is best to keep it one or two meters away. The advantage of salmon is that it can be lowered down the chain at any time, even when anchoring has already been done, which provides flexibility of use.
Other equipment that may be useful is the grippiale-one of the possible methods of releasing a captive anchor and indicating its location. Some possibilities are depicted in the figure above.
(a ) “Classic” case, the grippiale is attached to a float with a line as long as the depth. System only possible in areas without tidal excursion: it indicates the position of the anchor, but there is a risk of a boat passing by it with the propeller or perhaps someone confusing it with a buoy.
(b) In tidal areas, a weight can be interposed to try to hold the float on the vertical of the anchor. If there is only tide it works (with the limitations of case a), if there is some current the float is moved until all the spun line is unfolded, if small it often disappears underwater.
(c) Specific buoys with winding systems: the same considerations as in the previous point apply.
d) The grippiale line is returned to the boat: we lose the indication of the anchor’s position, but there is no risk of someone else ruining our anchor; the problem arises in areas of variable wind or alternative current as the line and chain tend to twist, eventually the line goes under tension and risks shipping the anchor.
(e) System similar to the previous one, but with a series of floats that keep the line separate from the calumus: this is the most multipurpose system.
(f) “Grippialino” just as good, the line is relatively short, with a small float: it assumes the possibility of being able to dive to go and fix a line. In all cases, keep in mind that unlocking a stuck anchor may require exerting significant tension, so don’t skimp with the diameter of the gripper line; among other things, since you often have to resort to the tender, your hands will also thank you for being able to handle perhaps 10-12mm of line rather than a 4mm line.
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