A downrigger solves one problem, and it solves it completely: it puts your lure at a depth you choose, and it keeps it there.
Everything else about the tool follows from that. If you understand why precise depth is hard to get any other way, the rest of it stops looking like a winch bolted to a boat and starts looking like the obvious answer.
The problem it solves
A lure has a depth it wants to run at. A spoon runs shallow. A deep-diving plug runs to maybe twenty feet if you give it enough line. Add weight to the line and you get deeper, but you have bought that depth with lead, and now the lead is between you and the fish. A big sinker deadens the action of the lure, it fights you the whole way in, and a modest salmon feels like a plastic bag.
You also have no idea where the lure actually is. Depth from added weight is a function of weight, line diameter, how much line is out and how fast you are going, and three of those four are changing constantly. You are guessing.
The downrigger separates the two jobs. The weight goes on its own cable, on its own reel, on its own boom off the side or transom of the boat. Your fishing line is clipped to that cable with a release. The lure runs at the depth of the weight, on an unweighted line, and when a fish hits, the line pops out of the clip and you are fighting the fish on a free line with nothing between you and it.
That is the whole idea. Depth control and the fight, decoupled.
The parts
A downrigger is a spool of cable or braid, a boom to hold it away from the hull, a pulley at the end of the boom, a brake or clutch, and a counter that reads out how much cable has gone over the pulley.
On the end of the cable is a weight, usually called a cannonball because that is what the round ones look like. Eight to fifteen pounds is the normal range for freshwater and inshore work. Heavier balls are for deep water and fast trolling.
Somewhere near the ball is a release clip, which holds your fishing line under adjustable tension and lets go when a fish loads it up.
That is it. Manual downriggers have a crank. Electric ones have a motor and a switch, and once you have hauled a twelve pound ball up from a hundred feet a dozen times in a morning, you will understand why they exist.
Scotty: How To Use A DownriggerBlowback, and why the counter is lying to you
This is the part that separates people who own downriggers from people who use them.
The counter on your downrigger does not measure depth. It measures cable. It counts how much wire went over the pulley, and it has no idea what that wire did afterward.
What the wire does afterward is trail behind the boat. The ball has drag, the cable has drag, and the faster you go and the lighter the ball, the further back it gets pushed. The cable leaves the pulley at an angle instead of hanging straight down, and the ball is now shallower than the counter says. That angle is called blowback, and it is the single largest source of error in downrigger fishing.
The arithmetic is ordinary trigonometry. True depth is the cable out multiplied by the cosine of the angle off vertical. With a hundred feet of cable out:
At ten degrees you are at about 98 feet. Nobody cares.
At twenty degrees you are at about 94 feet. Starting to matter.
At thirty degrees you are at about 87 feet, so you have lost thirteen feet you thought you had.
At forty five degrees you are at about 71 feet, and you are fishing a completely different part of the water column than the one you selected.
Nobody carries a protractor. You do not need one. Hold a hand up against the cable where it enters the water and get in the habit of comparing it to vertical, or mark the pulley housing so you have a reference. What you are looking for is not a precise number, it is whether you are in the ten degree world or the forty degree world.
The fixes, in order of how much they help: a heavier ball, a slower troll, less cable out, and thinner cable. A heavier ball is usually the right answer, and it is why people who troll fast for kings run balls that look absurd to a lake trout fisherman.
Downrigger Weight Size When Experiencing BlowbackSetting the release
The clip has to hold your line against the drag of the lure and let go when a fish takes it. Those two demands pull in opposite directions, and the tension setting is where you resolve them.
Too tight and the fish does not trip it. The rod loads up, stays loaded, and the fish is now towing a twelve pound weight through the water on a short leash. Sometimes it comes off. Sometimes the hooks tear. Either way you did not get a fight, you got a tug of war.
Too loose and it fires on everything. A wave, a weed, a change in speed, the lure fouling on itself. You will spend the morning resetting.
The setting that works is the lightest one that holds the lure at your trolling speed with a little margin. Set it, run it, watch it. If you get false releases, add a little. If you get fish that stay pinned to the ball, take some away. It is a per-lure setting, because a big paddle and a small spoon pull very differently.
One habit is worth more than any adjustment: after you clip in and lower away, crank the reel down until the rod is bent into a real bow. That bend is stored line. When the release fires, the rod straightens and takes up the slack for you, which is the difference between coming tight on a fish and watching a limp line drift back.
Setback
Setback is how far your lure runs behind the release clip. It is not a detail. It is the second dial on the instrument.
Short setbacks, ten or fifteen feet, put the lure right in the disturbance of the ball. Some fish do not care and some fish seem to like it, because a downrigger ball at depth looks like something, and a lot of trollers deliberately dress the ball with a flasher to make it look like more.
Long setbacks, fifty feet and beyond, put the lure well clear of everything and are the answer for fish in clear, calm, hard-fished water. The cost is that a long setback rises. The lure is on a line with drag on it, and the further back it is from the clip, the more it planes upward, so your actual lure depth is shallower than your ball depth by an amount that grows with setback.
Which is the honest summary of downrigger depth control: the ball is where the counter says minus blowback, and the lure is where the ball is minus setback rise. Precise is a relative term. It is still ten times better than guessing with a sinker.
Stacking
You can hang two rods off one cable. The lower one clips at the ball. The upper one clips to the cable ten or twenty feet above it, on a stacker release that grips the wire.
The reason to do it is that you are covering two depths on one downrigger, which matters when you are searching for a band of fish rather than working one you have already found. The reason not to do it is that bringing the ball up now involves unclipping in the right order while the boat moves, and a fish on the lower rod comes up through the upper rod's line.
Learn it after you can run a single rod cleanly, not before.
Choosing the depth
The whole tool is pointless without an answer to the question of what depth to pick, and the answer comes off the sonar.
Find the fish, then set the ball a few feet above them. Not level with them and not below. The standard reasoning is that these fish feed upward, so a bait passing overhead is in view and a bait passing underneath is behind them. That reasoning is a rule of thumb rather than a measured law, but the practice built on it is close to universal among people who do this for a living.
Also read the temperature. On the Great Lakes in summer the fish are stacked around a thermocline you can often see on the sonar as a fuzzy band, and finding it does more for your day than any lure change. Lake trout sit deep and cold and are the species most people learn downriggers on, because they hold still enough to let you make mistakes. Chinook salmon will make you work for it, moving through the column with light and bait. Coho salmon run shallower and faster than their bigger cousins and will take a lure trolled quicker than feels right.
It is not only a big water tool. Kokanee salmon in a western reservoir are a downrigger fishery in miniature, run at a crawl with tiny gear. Walleye suspended over a basin are a classic rigger target. Inshore, king mackerel get trolled on riggers along the southeastern coast for the same reason as everything else: the fish are at a depth and you would like to be at it too.
Speed
Ball drag rises steeply with speed. Everything about the rig gets worse as you go faster: more blowback, more strain, more noise.
The number that matters is speed at the lure, not speed over the ground. A GPS gives you speed over ground, and if you are trolling with a current or against one, the water is moving too, and the lure only knows about the water. On the Great Lakes this is a serious effect, because subsurface currents can run in a different direction than the surface. This is why people who troll seriously carry a probe that reads speed and temperature down at the ball, and why everyone else learns to troll in a big S so that the inside and outside of every turn tell them which speed the fish wanted.
Cable or braid
Traditional downriggers run stainless cable. It is cheap, tough and abrasion resistant. It also hums. Water flowing past a taut wire makes it vibrate audibly, and opinion divides sharply on whether that sound calls fish in or pushes them out.
Braid has largely taken over at the high end. It is thinner, so less blowback for the same ball. It does not hum. It is quieter to fish and easier on your hands. It is also less forgiving of a nick and more expensive to replace.
There is a related idea worth naming so you can decide what to do with it: some very experienced trollers believe a boat carries a small electrical potential into the water through the cable, and that the level of it affects whether fish approach. Devices sold to control it have been in use on the Great Lakes for decades. The underlying physics of a dissimilar metal in an electrolyte is real, and the fish response is not something you should treat as settled. Plenty of people catch a great many fish without ever owning one.
The gear
You do not need much, but the things you need are specific.
The downrigger itself is a real purchase, so buy for the water you actually fish rather than the water you imagine. If everything you do is under sixty feet on a small lake, a manual unit with a short boom is enough and will outlive you. If you are running a hundred and fifty feet on big water, hauling that by hand will end your enthusiasm quickly.
A word on safety before the list, because a downrigger is the most dangerous thing on most fishing boats. A cable under load stores energy, and when it lets go it does not let go gently. Keep fingers out of the path of the cable and off the spool. Never grab a moving cable to slow it. Watch the boom when someone else is cranking, and stop the boat before anyone leans over the transom to sort out a fouled ball.
Rules, and where to check them
Downriggers are legal gear on every water we are aware of, but the number of lines you may fish is not a national number and never has been. It varies by state, and inside some states it varies by which lake you are on, whether you hold an extra stamp, and whether you are fishing through the ice. A downrigger rod counts as a rod. Two rods stacked on one cable count as two.
Get that number from your state agency before you set a spread rather than from the boat next to you, because the boat next to you may be registered somewhere else. If you are on border water, both states have an opinion and they are sometimes different.
Access is the other half of it. A boat ramp is not automatically a public one, and a lake you can see is not automatically a lake you may launch into. Our fishing access laws by state explainer covers how that varies, and how to find public fishing access covers finding a legal launch before you drive to it with a boat behind you.
What it is really for
The unglamorous truth about downrigger fishing is that it is a search method. You are not casting to a fish you found. You are dragging a known depth through a large volume of water at a known speed until something happens, and then you are trying to remember exactly what you were doing at the moment it happened.
That is why the counters and the speed and the setbacks matter. They are not fussiness. They are the record that lets you repeat the thing that worked. Any fool can catch a fish. The point of running a rigger properly is catching the second one on purpose.
