When chunking for bluefin tuna off the Delmarva coast, I've found that the big ones feed near the bottom. Many anglers affix ten to 20 ounces of lead to their rig with a rubber band to get down to the strike zone. When the angler hooks a tuna, the fish's strong initial run breaks the rubber band. I replaced store-bought lead weights with economical and more environmentally friendly discarded iron railroad spikes that I found behind my place of employment. The spikes generally weigh between 14 and 16 ounces. I attach the spike to the line by looping a No. 32 rubber band over the head of the spike, then wrapping the band around both the line and the spike as many times as possible before looping the rubber band over the head of the spike again. I attach the spike to the main line ten to 12 feet above a six-foot leader of 50- to 80-pound fluorocarbon with a 6/0 to 8/0 circle hook. Lower the rig very slowly so the bait does not foul with the main line. Drop it to the bottom, then pick it up five to eight cranks. Set the drag just enough to keep the line from paying out. When the tuna takes the bait, throw the drag to strike and hang on.