You don't have much line in the water maybe 8 to 10' at the most and in most cases I have under 6' of line in the water per rod. You are not moving fast so tangled lines don't happen unless like already said you get in a stump field or a brush pile and they all get hungup. Gars are the worst problem I have had as fish species goes in tangling the lines but on a kayak you are only going to have 4 or 6 rods out at one time. I like to use 10 or 12' rods while spider rigging on my kayak and with the longer rods you have to be more alert of what is in front of you.
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Ascend 133X 13' - MotorGuide Xi3 & Mercury 4