I should have said that the 10mm floating rope that you see in the photo is run out to a buoy which has the main 3mm anchor warp via an anchor reel attached. This is the method we use when kayak fishing at sea and because the yellow rope is floating, there is no downward pressure on the boat bow so little or no slap. I fish mainly in the Humber area where there is a strong current but not a heavy chop and this method works well for me but I cannot really say how effective it might be in a heavy chop or really big swell.
You might say the anchor warp at 3mm is too thin, but I have found over the years that I have used this method, it allows me to use much lighter anchors. As a matter of interest I use a 0.75 kilo anchor on my kayak and hold ground very well, I also have a 1.5 kilo anchor which has never been used but I dare say will be used on the sib as there will be greater drag. When you fish from a kayak at sea, you have to use lighter gear otherwise you can get in a mess on such a small platform so we all tend to use light anchor warps and my other anchor is an aluminium divers reel loaded with 1.5mm line which also works very well in most conditions.
You are right Peter about the outer 'D' rings, the boat does have them but I wanted to create a more directional pull so I opted for the internal 'D' rings.