So ive been doing alot of jerk bait and jig fishing in this cold water but ive been looking for new areas to fish in thin cold 45 degree water. I started wondering about boat docks. Will winter fish use deep boat docks as cover in these cold months?

Absolutely. They'll hold surprisingly close to the bottom of them on warm, sunny days. Those black plastic dock floats give off tons of heat, so do the foam ones. The docks with good vertical structure under them that would hold fish without the dock are always the best. 

Blue nailed it. Just remember that it's not summer time. Slowww way down. But, yeah, docks will hold fish. No floating docks on my home lake. So I look Docks in sun and deeper docks. Work every pole you can cast to...do it slowly.

Dude you are on point with your bait selection. 5

they are great in the wintertime with the bigger swimbaits to....IE Huddleston 8".