Ditto with Buddy. That deep requires full sinking, not just a sink-tip. Right now at Henry's Lake here in Idaho the fish have moved into the shallower water (2-6 ft.) along the lake margins, so an intermediate (1.5 to 2 ips sink rate) line is called for. During the early season the fish are hugging the bottom so a full sinking line is not only desired but manditory.
I use a Class VI Sink-tip for my river fishing and never for the lake. I use full sinking as Buddy described and Intermediate lines for the lakes depending on whether I'm fishing the depths or the margins.
Kelly
Tight Lines,
Kelly.
"There will be days when the fishing is better than one's most optimistic forecast, others when it is far worse. Either is a gain over just staying home."
Roderick Haig-Brown, "Fisherman's Spring"