I use a five#. One of the ones that opens up, and the ring locks the four sections out… a typical kayak anchor. It is enough in the river I fish, if I can hook on a rock or something. You will drag anything a little, and that can be good as sudden jerks in current are not always a good thing.
Really big thing to consider, is style. Mine fastens the rope on the bottom, and then through a zip tie on the top. There is a loop on the top, but a zip tie is huge for when you hang up…. and you will. In a kayak in current, you can only safely pull so hard, so you want the zip tie to break so you lift it out from the bottom. Same ideal of a richtor that you can pull it out.
I think the 10 will be good… mine is light, but consider the style. I also use a float on the end to keep the rope up if I have to cut it, or unsnap in a pinch. You want “out” in any situation…. like a big fish, something coming floating down river, big change in wind. It all happens, and you need to keep options open in current, and in a kayak.
Where you attach it is huge as well, in the side and the kayak can get very tippy. I am just off center, and a foot makes a big difference. I will someday add a trolly sort of thing for shifting it to the front or rear, based on how I want to hold on the river. It is always easier fishing down river to remove snags and such.
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