To save time while bottom fishing, keep a selection of cotter pins in sizes 5/16″, 3/8″ and 7/16″ in your tackle box. Simply slide a plastic or rubber bead onto the main line before tying on a swivel. When you need to add weight to your line, bend open the split of the cotter pin and slip it over the line until the line passes through in the eye of the pin. Pass the ends of the cotter pin through the eye of a bank sinker and bend them back to attach the sinker to the line. The cotter pin will work on nearly any kind of sinker, including an egg sinker if the ends of the pin will pass through the center bore. Weight can be added without retrieving the line; simply attach the pin and weight and send it down the line. The bead prevents the pins from damaging the knot.
– Edmund Jacobs, U.S.S. Juneau