You may have heard an angler talk about "setting your drag" when fighting a fish. Drag on a fishing reel is an important feature that allows a fish to pull on the line without breaking it, ensuring that the fight will continue.
- To tighten drag means to tighten the spool so that more force is necessary to take line from the reel.
- To loosen drag means to loosen the spool so that less force is necessary to take line from the reel.
Drag mechanisms on fishing reels all function in a similar fashion regardless of the reel type. They provide resistance to the line being pulled from the spool. When set correctly, this resistance is set to less than the breaking strength of the line. When a fish pulls on the line with a force greating than the drag setting, it will begin to pull line from the spool.
Allowing line to feed from the spool accomplishes three things. First, it keeps your line from breaking when sudden force is applied. Second, it prevents your rod from being pulled out of your hands, or prevents you from being pulled into the water. Third, it allow the fish to expend its energy repeatedly taking line so it can be more easily landed.
Imagine you have a reel wound with 50 pound line. You have the drag set very light, let's say 3 pounds. You hook into a large fish, and it wants to run. The fish begins to run, and applies a force to your line of approximately 5 pounds. This force, being greater than your drag setting, breaks the drag and the fish starts taking line.
If you let the fish continue taking line, it could spool your line completely and get away. So you tighten the drag to 15 pounds or so. You start to reel, and you manage to reclaim a few dozen yards of line before the fish takes another run. But with a heavier drag, this run is much shorter, and the fish is clearly burning off a lot of energy. It's now just a matter of time until the fish can be reeled in enough to be landed.
If at any point your drag is tightened past the weight rating of the line on the reel, and more force is applied to the line than its rated breaking strength, the line will break. You never want to tighten the drag so much that it exceeds your line's weight rating.