Try a Big Jon Deeper Diver (google it). The 2" model will get you down to 45-50 feet using 10lb braid, much deeper than the equivalent dipsy or slide diver. While you can't use it with an ultra light rod, it works fine with a light action (4-10lb test) spinning rod. It will put a bit of a bend in the rod while trolling, but no more than a deep diving plug (like a yo-zuri crysal or a Bomber 24) would. And when a fish it feels the same as just having a slingblade and hoochie on. A lot better than using lead. Not as good as a downrigger but if you only fish for kokanee periodically, like I do, the small divers are an acceptable alternative.