Unless there are big rocks in the dam I leave both packs in. I run the boat onto the dam, or at least into the sticks on the low side, then crawl over the front pack. The bow is partially supported by the sticks. I often have to grab a stick and squeeze it against the gunnel with one hand to keep the boat from moving backwards as I crawl forward. Once out on the dam I heave the canoe over and get back in. I usually just grab a paddle to stick in the stern as it slides off the dam, rather than untying a painter. The only tricky situation is going upstream, when I have to drag the canoe basically straight up, with the bow in the air, until the main pack (50 lbs) in the back is level with the top of the dam. Then I pull down the bow and slide the boat in. The pack is right on the dam when I pull down. If I just pull straight over with the bow low, the weight of the pack in the back bends the canoe across the dam and the canoe can crack
Light weight kevlar has its limits.
I can only recall getting wet once. I was going downstream, the dam was three feet high, it had many long sticks on the downstream side. There was another dam just downstream so the water on the low side was waist deep. The stern was about three feet from where I was standing, so I took a giant step down and into the stern. With my big pack in the back and all my weight even further back, the stern submerged, the boat was wildly unstable, and I did a graceful back flop into the beaver pond, swamping the boat. The move has worked fine on many other dams, because on the downstream side the water is usually very shallow, so the stern just hits the bottom. If I ever get in the same situation again, with deep water, I am going to try a superman style dive onto my stomach onto the main pack.
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shearjoy Sometimes your joy is the source of your smile, but sometimes your smile can be the source of your joy. Thich Nhat Hanh