Zen,

I don't fly fish, but do slow troll with wolly buggers alot for trout and have noticed that I get alot of "short strikes". When this happens I cut the motor ( battery operated) and drop my rod back a few feet creating slack and "fish on" - your explantion clears up the mystery for me, I always though it was just moving too fast.

In lakes with green colored water, I have had my best success with olive or black/olive wolly buggers and the cracked frog flatfish which is green and yellow. Maybe I need to get some chartreuse buggers.