I have a Rule bait pump on my boat. It's below the water line + a thru-hull scoop (yes it is facing forward), and I still cant get it to self-prime even when cruising at 18kt. I always end up twisting the pump off so water fills in for a second before re-attaching and turning it on.
I've always wondered about how a kayak would do it. I presume a primer bulb would work great on yaks even with the smaller diameter because you don't need the kind of GPH flow that a boat requires.
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