You’re right about the mechanics of the Ottertail, but they’re are exclusively lake paddles, right? I need something for shallow streams and currents also. Currently using a BB Explorer, which is 23 oz, 118 sq in blade.
Not to answer for ScottS, but I think you are right about otter tails being more lake paddles. However I also saw you were thinking about a beaver tail. While a beaver tail does carry more width lower in the blade which does help in shallower water, it is still not really ideal for shallow currents, at least in my experience. I have a badger paddles badgertail (their beaver tail design) and I also pretty much exclusively paddle rocky streams with alternating shallow (sometimes super shallow) and deep areas. I love the paddle but I only really use it in the deep/slower pools for two reasons. One, it doesn’t get enough bite in the shallows. Two, because it doesn’t get as much bite, I naturally tend to start digging deeper and invariably hit bottom with it. This is unacceptable because it’s just too pretty to beat up like that (not sure if all their paddles are like that but mine at least is a VERY nice piece of cherry -it’s a work of art and a joy to use). They’re also usually longer than a design like your explorer, so in shallow water you have to lift them pretty high, which gets awkward and robs your leverage - possibly not great for the shoulder issue. I guess what I’m saying is while a beaver tail is better in shallower water, don’t expect it to be worlds better than an otter tail as neither are really geared toward shallow rocky streams.
Rather than damage my paddle with what invariably devolves into awkward seated poling, I usually switch off to a tougher, shorter paddle when I get close to the end of the deep pools now. I personally don’t mind switching off because it lets me use more of my paddles more frequently, and for what they’re good at. Adopting a similar practice might at least save your shoulder in the deeper stretches where you could use a beaver or otter tail, and then still give you the familiarity and benefits of your explorer in the shallow stuff. You gotta carry more paddles, but half the fun of paddling is using different, nice paddles for what they excel at (at least for me).