Mark the Shark demonstrates how to replace fishing line on a reel for deep sea fishing. First make sure to thread the fishing line into the guide ends and that you don't miss any. Put the rod in the rod holder so that you have two free hands to work with the line. Thread the line twice in the spool and make a knot to hold the line in place. Pull the line tight so it's snug against the reel and snip off the loose ends. Turn the crank and make sure that the line feeds into the spool very evenly. Go from end to end. Put the line spool supply source in a bucket of ice to keep it lubricated. Keep tension on the line the whole time so it goes smoothly on the reel when replacing the line.