Every other trolling tool answers the question of how deep. Planer boards answer a different one: how wide.
A boat is about eight feet across and it drags a disturbance behind it that is a good deal wider than that. Fish in shallow water, in clear water, or on water that gets fished hard every weekend do not sit in that disturbance. They move out of it. A planer board is the device that lets you fish where they went.
What a board does
A planer board is a float with an angled face. Towed forward, that angle makes it cut sideways instead of following, the same way a kite pulls away from the person holding it. Attach your fishing line to it and the line goes out with it.
The result is a lure running fifty, eighty, a hundred feet off to the side of your track, in water nothing has been through. It is also running shallow, because a board is a surface device and it holds the line up rather than pulling it down. That combination, shallow and wide, is not something any other trolling method delivers.
There are two families of them and they solve the same problem at very different scales.
Inline boards
An inline board is small, it clips directly onto your fishing line, and it travels out with the lure. When a fish hits, the board is still on your line, so you reel in the fish and the board together.
They are the format almost everybody starts with and most people stay with. They cost little, they stow in a bucket, they work on any boat including a small tiller boat, and setting one is a fifteen-second job: clip it on, drop it in, let line out and it swims away.
Some inline boards are designed to release when a fish strikes, sliding down the line to a stop above the leader so you are not cranking a board through the fight. Others hold on and come in with everything. Both approaches are in wide use and the choice is mostly about how much you dislike reeling in a plastic board on every fish.
How To Use an In-Line Planer Board to Troll for Trout and SalmonMast boards
The other family is the big-board system. One large board on each side, towed on a heavy line from a mast on the bow. Your fishing lines are clipped to that tow line with releases, the same idea as a downrigger release. When a fish hits, the line pops out of the clip and you fight the fish on a completely free line with no board attached to it at all.
The advantage is the clean fight and the number of rods. You can hang several lines off one tow line at staggered distances, and a boat running mast boards on both sides plus gear down the middle is presenting a genuinely wide pattern.
The cost is that it is a real installation. There is a mast, there is heavy tow line, there is a winch or a lot of hauling, and the whole rig has to come in before you can do anything sudden. It is a big-water, all-day setup, not something you deploy for an hour on a small lake.
The tattle flag, and why it earns its keep
Most inline boards have a flag, and the good ones have a flag on a spring.
A board is a long way away. You cannot see your rod tip do anything useful, because the rod is loaded by the board rather than by the lure. What you can see is the flag. A spring-loaded flag drops when the pull on the line changes, which means it tells you three things you would otherwise miss entirely: a fish is on, a small fish is on, or your lure has picked up a weed and stopped working.
That last one matters more than people expect. Trolling a fouled crankbait for forty minutes is a completely wasted forty minutes, and without a flag you find out at the end of it.
Running more than one a side
This is the whole reason to own boards, and it is where the discipline comes in.
Boards are staggered by distance. The outside board goes out furthest with the most line, the inside board sits closer, and there is real separation between them. Conventionally the two sides get different colored boards, and most manufacturers make the port board red, which means a glance tells you which side you are looking at without thinking about it.
The order of operations is the part that catches people out. When a fish hits the inside line, the inside board has to come in past nothing, so that is easy. When a fish hits the outside line, the outside board has to come in across the top of the inside line, and if you do it carelessly you now have two rods, one fish and one knot. The answer is either to clear the inside board first, or to steer the boat so the fish's line lifts clear, and it is worth deciding which one you use before it happens rather than during.
How to Retrieve a Single Planer Board Without Tangling in a Multi-Board Trolling SetupTurns are the other hazard. In a turn the inside board slows down, loses its pull and can fall back and sink, while the outside board speeds up and planes harder. Wide, gentle arcs keep everything where it belongs. A hard turn with four boards out is how a good morning becomes an hour of untangling.
Lead length, which is the setting nobody explains
Before the board goes on, you let the lure out behind the boat. That distance, from the lure to where the board clips on, is the lead, and it is a genuine control rather than a formality.
A short lead, twenty or thirty feet, keeps the lure close under the board. It is easy to manage, it turns tightly with the board, and it is what you want when you are working a contour and need the lure to actually follow the path you are steering.
A long lead, seventy feet or more, puts the lure a long way behind and below the board. With a diving crankbait, a longer lead is also a deeper lure, because a crankbait dives as a function of how much line is out in front of it. So the lead is doing two jobs at once here: distance from the board, and depth.
That double duty is the thing to hold onto. On a board rod, letting out more line does not simply move the lure back. It moves it back and down, and if you are trying to hit a specific depth with a specific crankbait you need the lead to be a number you set deliberately rather than however much felt right when you dropped it in.
Reading what the board is telling you
A board is an instrument as well as a tool, and learning to read one is most of what separates a good board fisherman from someone dragging plastic around.
A board running correctly sits up, tracks a steady distance out, and leans consistently. Anything that changes is information.
A board that falls back toward the boat has lost pull. Usually that means weed on the lure, sometimes it means the boat slowed, occasionally it means a fish that is swimming toward you. Check the flag, then check the speed, then reel it in.
A board that suddenly surges forward or starts to skate is going too fast for its load, which happens on the outside of a turn or when a following sea picks the boat up. It will usually sort itself out. If it does not, you are trolling too fast for the board.
A board that is riding low and wet is carrying more than it should. Too heavy a lure, too much lead core, or line that has picked up something. Boards have a load limit and exceeding it does not produce an error message, it just produces a board that half works.
And a board that has stopped moving relative to the others is often the first sign of a fish that has not yet dropped the flag. Watching all your boards as a group, rather than each one individually, is how experienced trollers see bites early.
What you hang off a board
Anything that does not pull too hard for the board to handle. That is the real constraint.
Crankbaits are the standard, because they dive to a known depth on their own and a board does not stop them doing it. A board plus a crankbait is a controlled depth in uncontrolled water, which is why it is the walleye trolling rig on most of the Great Lakes and most of the big reservoirs.
Lead core behind a board is the quiet deep-ish combination and one of the most effective presentations in freshwater. Nothing hard is in the water, the line sinks on its own, and the whole thing is a long way from the hull.
Spoons and stickbaits run shallow and are the answer for brown trout and rainbow trout cruising the top ten feet in spring, which is the classic board fishery: fish so shallow and so spooky that a boat passing overhead ruins the spot.
Inshore, striped bass in shallow bays and flats get boards for exactly the same reason.
When boards are the wrong answer
They are not the tool for deep fish. A board holds line up, and if you need to be at ninety feet you want a downrigger and possibly a diver instead. Boards and riggers coexist happily on the same boat, covering different parts of the same water, and that is the usual arrangement rather than a choice between them.
They are also wrong in tight water. A board a hundred feet off your beam needs a hundred feet of clear water on that side, and in a narrow river, a crowded launch bay or a channel with traffic, that is not something you have. Boards demand space, and taking them where there is none is antisocial as well as unproductive.
And they are wrong in a big following sea, where a board spends more time airborne than working.
One more case worth naming, because it surprises people: boards are wrong when you are still looking for the fish. A four-board spread takes real time to set and real time to clear, and while it is out you are committed to a course. If you do not yet know what depth or what contour you want, a single rod off the back tells you more per hour than a wide spread does, because you can change it in thirty seconds. Boards are a tool for exploiting a pattern you have found, not for finding one.
The gear
The list is short and the boards themselves are the cheap part.
Inline boards in pairs, port and starboard, and more pairs than you think. They are inexpensive, they get lost, and a spread wants at least two a side.
Long rods, eight feet or more, with a soft tip. Length reaches out over the water and keeps line clear of the hull, and the soft tip lets you see the flag work rather than fighting it.
Line counter reels, again, because board distance is the variable that separates one board from another and keeps them from meeting.
Monofilament, in most cases, rather than braid. This is one of the few places mono is genuinely preferred: it stretches, which keeps a board from popping off on a wave, and it has more drag through the water, which helps a board pull.
Board releases or clips appropriate to your boards, plus spares. They are small, they are the moving part, and they go over the side.
A rod holder set that spreads rods across the beam. The whole point is separation, and four rods in two holders side by side gives you none.
And a long-handled net, since the fish arrives outboard of the boat with a board somewhere on the line.
Rules
Nothing about a board is unusual gear, but it does not change the count. Rods per angler is set by each state, varies by water and season in some of them, and every board rod counts. A boat running four boards plus two riggers has six rods out, and that is a number worth checking against the regulations for the specific lake you are on, not the state generally, and against both states if you are on border water.
Our fishing access laws by state explainer covers how much this varies, and finding public fishing access covers getting the boat in the water legally to begin with.
The honest summary
Boards do not catch fish that riggers cannot reach. They catch fish that a boat scares.
That is a narrower claim than the marketing makes, and it is also the reason boards are on almost every serious trolling boat in the country. Spooky shallow fish are a large fraction of the fish worth catching, and there is no other way to put a lure in front of them from a boat without the boat getting there first.
