A little confusing I agree, but I get the gist and will try and explain.
Basically the author is explaining how to avoid and or deal with a situation when the anchor chains of 2 (or more) boats become crossed when docking stern to a quay, a very typical docking method in the Med. The crew determine where on the quay they wish to tie (stern to) and whilst backing towards this spot, drop their anchor and continue playing it out until they reach the quay. After tying the stern of the boat to the quay, they take up some tension on the anchor chain to keep the boat from hitting the quay as it moves around in the wind.
The problem comes when many boats are all tied in this manner to the same quay, an extremely common occurrence especially in season in popular harbours. The dock master will squash as many boats as possible onto the quay such that the boats will be pressed beam to beam like sardines in a tin. Now, assuming you manage to drop your anchor in a perfect line in front of your boat, as well as the guys either side of you and perhaps even the guys outside of them then you have no problem, but this is rarely the case. Often you may be docking with a side wind making this manoeuvre a little tricky and inevitably you may well misjudge and drop your anchor a little to windward of your space on the quay such that when you play it out and tie up, you have laid it over the top of someone else’s chain (probably the guy you are now alongside). Alternatively the same may happen when another boat docks next to you. This happens so often that it is more or less normal and is no reason to get angry (as many do), just be aware of how to deal with it.
The problem comes when you now wish to leave the dock before someone next to you who has his chain laid over the top of yours. Knowing the situation it’s probably worth letting your neighbour know you’re leaving so he can help as necessary. As you leave the quay lifting your chain, your chain will slip from underneath your neighbours, ultimately however, your anchor will hook your neighbours’ chain and as you continue to lift his chain comes up too.
So…. Now you have your anchor at the surface and the chain of your neighbour laying over it preventing you from being able to bring it aboard and stow. Your neighbour should also be aware that this might have tripped his anchor such that it’s no longer holding and preventing him from drifting back into the quay. Your neighbour should start his engine and put it in forward gear at low revs to prevent this from happening, he should then reset his anchor after you have left.
To remove the chain from your anchor, the previous author is suggesting taking a hook on a rope to hook the chain, once hooked the hook/rope assembly can be tied off tightly to a bow cleat. Lower your anchor to free it and then lift it again past the suspended chain and stow it. Now you can drop the suspended chain.
However, I personally would recommend a slightly different approach that I have successfully used, as I can’t see how you now get your hook un-hooked from your neighbor's chain. Alternatively, I take a short rope, tie one end to a bow cleat, pass it under the fouled chain, then pull it tight and tie it back to the same cleat. Now I lower my anchor to free it from the neighbor's chain and once clear lift it aboard and stow it. You may want to use your boat hook to orientate your anchor to not hook the suspended chain as it passes again on its way up. "
Once your anchor is safely stowed, undo one end of the rope suspending your neighbours’ chain and let it slide away, finally pull aboard the rope AND OFF YOU GO…….
I have used this method hundreds of times for all sorts of fouled lines and chains on my anchor, including once a 4” power cable which was so heavy I could only get it to about 20 foot of the surface. On this occasion I took a longer line, tied off one end and swam with the other underneath the cable and back to the surface before tying it off to the cleat.
I hope this all makes sense.
Capt. Ian G. Fagg