How to catch river b?

I am a avid fisherman that is fairly knowledgeable and seem to be having a hard time catching these monster b that i see swimming all day long, but cant seem to catch them, i have tried all sorts of colors and sizes and still i cant come up with a solution. catching smaller b seems to be no problem, but lets be real here, being a serious, devoted b fisherman, you want to go for the gold... any suggestions?