Downrigger Operation – How to use a downrigger for trout fishing

Salmon limit bag from Lake Coleridge caught with the aid of a Scotty electric downrigger.
Salmon limit bag from Lake Coleridge caught with the aid of a Scotty electric downrigger.

Downrigger Operation – Putting It All Together

Safety First

Downrigger operation is simplicity itself; however, safety must be our first consideration. There are several ways to get into trouble while operating a downrigger, so we had better cover those first. Take it easy at the start and don’t be in a rush. Using a downrigger for trolling soon become second nature after a bit of practice.

The arm, or boom, on your downrigger, is moved up and down during normal op­eration. In order to set the line in the re­lease clip, the boom is lifted inboard. On the larger Scotty models, there is a locking device to hold the arm in the raised position. It is important to swing the boom up rather than reach over the side to grab the wire cable. If you lean over the side sooner or later you’ll fall overboard!

Al­ways remember to lower the boom slowly. Don’t just let it drop down or damage to the boom could result, particularly with heavyweights. Keep the floor area around the downrigger free from obstructions such as tackle boxes, fuel containers, and other clutter. This is particularly important in a smaller craft. In the sudden excitement that follows a strike, it is all too easy to get tangled up and fall over. When a fish strikes you have to grab your rod and get the cannonball up out of the way so you can play the fish without it swimming around the cable! The last thing you need is an obstacle course in the way.

Scotty or Cannon Downriggers?

Which is better? I can assure you that both of these brands are durable and great fish takers. I have had extensive use with a number of different Scotty downrigger models from the small Lake Troller all the way up to their top of the top of the line electric models. On the otherhand I have never owned a Cannon downrigger but have been out on boats when they have been used. The cannon owners have always reported that they are of excellent quality and easy to use. A good analogy would be which is better, Canon or Nikon cameras. The answer is they are both good!   

Sitting Down Downrigger Operation

Unless your craft has a reasonably high transom and gunwales you are better to work your downrigger from a seated po­sition if possible. This way you lessen the possibility of slipping or falling, particu­larly if the water surface is a bit choppy. In short, consider what you are going to do in the event of a strike ahead of time.

When a fish takes, will you continue run­ning forward at trolling speed, or will you cut the engine? When lake fishing for trout I prefer to shut the engine off when a fish strikes. This not only does away with the noise, but it also slightly reduces the need to keep a constant lookout ahead! This is a very im­portant consideration, particularly in crowded conditions. It’s bad enough hav­ing to play the fish, and lift the cannon­ball up to the boat, without having to con­stantly lookout to avoid a collision, bring in any other lines your crew has out, plus avoid running ashore, all at the same time! All this is made simpler with the assist­ance of a good crew member. By allocat­ing tasks ahead of time, it will pay off when a fish strikes.

It is quite possible for one angler to fish a downrigger, and operate the boat on their own. I have done this without diffi­culty.

First-time downrigger operators might like to spend a few moments think­ing about what happens when a fish takes the lure.

1. Lift the rod from the rod holder. The line will now be free of the release clip.

2. Cut the engine.

3. Quickly wind in any other trolling lines – better still have your mate wind in his line to prevent the lure catching on the bottom.

4. Raise the cannonball so the fish doesn’t wrap the mono around the stain­less steel cable.

If you have an electric downrigger model raising the cannonball out of the way is just a matter of flicking a switch. The electric models also feature an adjustable stopper on the cable that operates a “dead man’s” switch to cut the electric motor when the cannonball reaches the surface so it doesn’t whack into the arm – what luxury! If you have a manual model, you, or a crew member, will have to wind the handle to lift the cannonball clear, at the same time as a fish is being played on the rod.

5. Maintain a constant lookout at all times to avoid a collision or running aground. Don’t laugh! When playing about with your downrigger you will gen­erally be looking aft. If you are focused on operating your motor from the transom position, again you will be spending time reaching over to put it in gear and set the throttle. It is easy to become so involved looking out the back, particularly when you hook a fish, that you lose perspective on where your boat is headed. So a proper all-around lookout is essential at all times.

All this might sound a bit complicated, to begin with, but after a couple of fish downrigger operation quickly becomes second nature – or even a reflex action!

Basic Downrigger Setup A downrigger uses a separate wire cable and heavy weight to take your lure down to the fish. Once a fish has pulled the rod line free of the release clip it can fight freely with no additional weight on the line. The diving depth of bibbed minnows trolled behind the cannonball is determined by the length of drop-back from the release clip. A shorter line will restrict diving depth.
Basic Downrigger Setup A downrigger uses a separate wire cable and heavyweight to take your lure down to the fish. Once a fish has pulled the rod line free of the release clip it can fight freely with no additional weight on the line. The diving depth of bibbed minnows trolled behind the cannonball is determined by the length of drop-back from the release clip. A shorter line will restrict diving depth.

Hitting Bottom

A final safety point to remember is set­ting the drag on your downrigger cor­rectly. Everyone snags the bottom sooner or later! Mostly this simply results in bringing up a bit of weed. However, it is potentially very dangerous, especially in a smaller boat because if the cannonball catches around an obstacle; such as rocks or a sunken tree trunk, and your drag set­ting is too tight, it could possibly pull the transom under the water, or even rip the transom off your boat completely. The danger of being swamped by water com­ing over the transom, caused by a snagged downrigger ball, and over tight drag set­ting, is increased in rough conditions. Personally, I wouldn’t fish a downrigger in marginal conditions. If you are worried about this you might like to keep a pair of cutters close by so that in an emergency you could always snip the cable. The worst that could happen is that you would lose the can­nonball and a bit of wire cable.

Fortunately, this is easily avoided by setting the drag in such a way that if the cannonball does snag on the bottom, ca­ble will simply be stripped from the downrigger spool giving you time to cut the motor and back up. You can set the drag on your downrigger on dry land. Set it so that you can still pull the cable off the spool, with the downrigger in gear, with­out too much effort. For this same reason, you should not fish your downrigger with all the cable out because there would be nothing left for the clutch to release if the cannonball should snag.

When used with a depth sounder to track the contours of the bottom there is little chance of getting snagged. Watch the pulley on the end of the downrigger arm. It will bounce about if you hit bottom. I prefer to have my cannonball no deeper than a maximum of half the water depth when lake fish­ing. This usually gives you plenty of time to lift the cannonball up a couple of winds as the water gets shallower. Most depth sounders also have a useful warning buzzer which you can set to sound at any water depth. This is handy if you are fish­ing unfamiliar water.

Keep in mind also that if you are fishing a bibbed minnow with the aid of a downrigger the minnow will be diving down deeper than the cannonball.

I know it has nothing to do with downriggers but I’ll mention it anyway. Never go out on the lake unless you are wearing your life jacket. Even when the lake surface is flat calm; still wear your lifejacket with the straps fully fastened. If you fell overboard and knocked yourself unconscious on the gunwale your lifejacket could keep your head above water long enough to survive. Don’t just make your kids wear theirs while you don’t. Be a good role model. When fishing distant isolated lakes from small boats there is always the potential to end up in the water. If you put your lifejacket on every single time, before you climb into your boat, you’ll never be caught out not wearing it!

Catching Fish

With safety covered we are finally ready to start fishing. I like to rig my rods before launching including selecting my first lure for the day and tying it on. Having your rods fully rigged and sitting in their rod holders makes things easier once you get underway. You can start fishing as soon as you get out on the water!

Now out on the lake begin by having your boat running for­ward at a slow speed. This will avoid tangles! For trout trolling you only want to be going at one or two knots, or a slow walking pace. The boat speed to select also depends to some extent on the type of lures you are fishing, more on this later. But remember you only want to be going very slowly through the water. Go too fast, and you’ll catch noth­ing.

A Quick Word On Motors

My preference is to run a small 6 hp Johnson auxiliary outboard motor for trolling. This thing is very economical to run. It also means that the big motor doesn’t oil up – as it has a tendency to do at slow speeds. Though with modern outboards the old oiling-up problem is now a thing of the past.

However, the main problem with big engines is difficulty getting the boat to run slowly enough for trout trolling. There are attachments known as trolling plates that you can buy which connect to the leg, or anti-cavitation plate, of your outboard motor. These act as a baffle to deflect propeller thrust sideways and downwards and so reduce forward speed. I haven’t used a trolling plate attachment myself. Those who have reported mixed results. Some guys swear by them while others report difficulty steering at slow speeds. Many boaties are also put off by the need to drill holes in their outboard motor’s cavitation plate to attach them. These plates do work as a mate of mine uses his to effectively troll for trout with his 115hp Yamaha.

A second auxiliary motor for trolling has the following advantages; cheaper to run; better directional thrust; acts as a backup should your big motor not start; can be used on a second smaller craft.

Downrigger Operation Lures Out

Next cast out the back if fishing spin­ning gear, or feed the lure over the tran­som if you are fishing a trolling rod not designed for casting. How far back the lure should depend on two differ­ing schools of thought. Don’t be afraid to experiment to find out what works best for you on particular water. When sea fishing albacore tuna and other species will take lures in the prop-wash right behind the boat. I have found that when fishing on smaller lakes trout will take a Tasmanian Devil or Rapala minnow trolled 100 m or more behind the boat.

Your lure only needs to be 20 feet back before clipping the line into the release clip and lowering the cannon­ball. The belief is that trout or salmon swim up to the cannonball for a look. Its curiosity being aroused it decides to fol­low this strange thing that has entered its domain. Then suddenly the lure appears close behind and is snapped up by the in­vestigating fish.

The second school of thought is that the lure should be at least 50m, or more, behind the boat before setting the line in the release clip and lowering the cannon­ball. The idea here is that the boat is fright­ening the fish, and so the lure should be as far away from the boat as possible so the trout doesn’t associate the lure with the boat!

I have often asked successful anglers how far they drop back their lures before setting them in the release clip. Interestingly I have received a wide range of answers to this question.

Take your pick as to which view is correct! I tend to think the second op­tion is the better one in clear shallow wa­ter. I have observed rainbows swim out of the way of a slowly approaching boat in water less than four metres deep. In this situation, you want the lure well behind the boat. It is also worth drifting and casting in clear shallow water when you can see fish. Again, experiment to see what works best.

With the lure now out behind the boat we can set the monofilament fishing line into the downrigger clip. Lift the boom aboard first and lock it in place. Have the clip set reasonably tight so that the fish needs to give a good solid pull to free the line. If you set the clip pressure too lightly the hook won’t set properly, and you’ll also spend all day winding in to reset the line in the release clip be­cause of false strikes. I fished on lakes for many years with a 6 lb monofilament line – I now use braid. It’s sur­prising just how tight you have to set the release clip for it to work effectively, even with such a light line!

With the line now in the release clip, keep your finger on the spool of your fishing reel so line doesn’t fall off too quickly causing a tangle be­fore lowering the boom, and pulling the lever forward on the downrigger to start the cannonball, clip, and line descending.

Never fully release the clutch so the cannonball falls freely. If you do kinks will develop in the cable. Lower the cannonball and fishing line together in a steady deliberate manner. Don’t allow the cannonball to simply drop at high speed or tangles will result!

After the cannonball has descended to the desired fishing depth, stop releasing ca­ble from the downrigger and place the rod in a rod holder. Keep an eye on your rod tip and you’ll soon know when a fish hits because the rod tip will suddenly jerk and spring back. If you should miss see­ing this happen you can tell if the line has come free of the clip by the angle the line is running down from the rod tip.

Before a fish strikes the line will be pointing down at an angle only slightly less acute than that of the downrigger cable. Once a fish strikes and pulls the line from the clip, the line will be pointing well astern, where you would expect it to be if you were trolling a lure without the aid of a downrigger.

How Deep?

How deep to set your cannonball de­pends on several factors.

1. How deep are the fish?

2. Past experience.

3. Water depth.

4. Lake being fished.

5. Time of day.

6. Weather conditions.

Sonar is Essential for Efficient Downrigger Operation

When trolling in lakes you will often notice that most of the fish appear on the sounder at a particular depth. An elec­tronic sonar (sound navigation and rang­ing) device is almost a necessity when trolling with the aid of a downrigger. I have used a small Scotty Lake Troller without Sonar without any problems. However, a Sonar device will make your downrigger operation safer, more productive in terms of fish caught, at much more enjoyable. Sonar is so inexpensive these days that even the most modest craft has a sounder of some description. The sounder is the angler’s eyes underwater. It provides the downrigger angler with a con­stant “view” of the bottom depth making it possible to avoid snagging the cannon­ball.

When trolling on a lake if you aren’t seeing any fish on your “fish-finder” sonar then it’s time to reel in your lines and try somewhere else on the lake. It is reassuring to see fish on your sonar screen even if you can’t convince one to hit your lures!

A sounder not only indicates the presence of fish, which as I say is very reassuring but also their depth in the water column. For ex­ample: while following the bottom con­tour around the margin of a lake in 30m of water, you might discover that most fish are showing at 10m to 13m, and so you can set your cannonball depth accordingly. The fish may be at this particular depth because that is where the thermocline is.

During high summer you may find that the fish will be much deeper. In a shallow lake, they will likely be trying to avoid the heat by staying close to the bottom where the water may be a few degrees cooler. Trout are very sensitive to water temperature and will move up and down the water column to remain within their preferred temperature range. As you gain more experience fish­ing a particular lake you begin to know where the best places are to fish and at what depth you can expect to find fish.

In most South Island lakes the best trout and salmon fishing, that is if landlocked salmon are present, will generally be at the head of the lake where feeder streams or rivers enter. Therefore if you are fishing a new body of water for the first time the head of the lake will be the best starting point. Also, try where other streams and rivers enter the lake.

Time of day also plays a part in where fish will be found. In the early morning and evening, and at night, fish are often closer to the surface. This is also the case when there is a bit of chop on the water. As the sun rises trout and salmon will usually go down to deeper cooler water.

In many of the North Island lakes the water temperature heats up as we get into summer. Over the warmer months trout will be much deeper; most of the time at depths below 25m. Deep trolling is the order of the day if you are to catch them. At such times downriggers really come into their own. Jigging is also popular on these North Island lakes but in my experience is rarely used in the South Island. Your sonar device will make a huge difference when jigging for trout otherwise you will just have to guess and experiment to find the correct depth by trial and error.

Long or short Line?

The longer the line you have out the deeper the lure will sink. That is, within reason. If you let out too much line the lure will actually start to rise towards the surface as drag becomes a factor. Generally speaking – it depends on the lure – if it runs at a depth of say 20 feet with just 60 feet of line from the downrigger release clip, it will likely dive to 30 feet should you let out an extra 200 feet of line. This is particularly so with deep-diving plugs. All this is important to consider because you may actually be fishing your lure quite a bit deeper than your downrigger cannonball. Generally speaking in clear or shallow water let out more line before clipping them into the release clip.

Line Diameter

Another factor is line diameter. “The thinner the diameter of your line, the deeper the lure will dive. I almost always troll with 6 lb mono. But it is the line’s diameter that is the most important. Daiwa Samurai Green 6 lb monofilament has a line diameter of .22mm. By way of comparison, I have an old spool of Ultra Damyl 4 lb mono that has a diameter of .20mm. So in this case there is only 0.02 of a millimetre to be gained by going down to this 4 lb line weight.

If you fish a short line, with the lure close to the clip, you are more likely to be fishing it at the depth you desire, espe­cially if it is a soft plastic or some other lure that is less likely to dive deep. On the other hand, it can be very difficult to judge the actual depth of a bibbed Rapala fished on a light line 100m behind the cannonball, other than to say it will be running much deeper than the cannonball itself.

More Fish Are Caught on the Downrigger

In my experience, if there are several anglers in the boat trolling their lures for trout most of the fish will be taken on the downrigger. I have noticed this in Lake Coleridge in particular. Especially so on a sunny day and or when the water is calm, the downrigger will outfish trolled lures on a flat-line at a ratio of 4 to 1.

Boat speed paddle wheel indicator at left, and sonar transducer, right, on the transom of the author's boat. Essentials for downrigger operation.
Boat speed paddle wheel indicator at left, and sonar transducer, right, on the transom of the author’s boat. Both are important when trolling both with and without a downrigger.

Boat Speed

Boat speed is also an important factor in determining lure run­ning depth. As a rule, the slower the trolling speed the deeper the lure will run. One of the biggest mistakes made by anglers new to trolling is to go too fast. For trout trolling optimum speed is generally less than 2 knots. The lure used decides the trolling speed. Generally, a slow walking speed is about right for trout and landlocked salmon. A trout is not going to chase your offering all around the lake at high speed for an extended period trying to catch it! The same applies when spin fishing for trout. If you wind too fast you will catch nothing! It is better to err on the side of trolling too slow than too fast!

Experimentation plays an important part in learning about efficient downrigger operation. If you aren’t getting strikes when passing through areas that have plenty of fish showing on your sounder then try something different. Try trolling at a much slower speed. Swap out your lures for something different. You will often find that if you are trolling four different lures that most of the strikes may occur on one particular pattern.

Try trolling a feathered lure instead of a hard-bodied minnow. Try a segmented Rapala as these really vibrate and seem to attract more hits. I have found that bibbed minnows usually outfish aqua foils like the Tasmanian Devil. Whereas in other lakes the opposite may be true.

Keep a notebook in your tackle box and record the lures that have worked best for you in different waters. Note the time of day and time of year, lures used, colours, where on the lake you were fishing, trolling depth and speed, and so on. This information will enhance your downrigger operation and angling experience and as time goes by. I will help to reduce your strike rate per hour fished.

Downrigger Operation Checklist

It might seem obvious but having a checklist can save you a great deal of frustration. Tick each thing off your list as you load your gear into your boat and vehicle. Have you loaded your rods and reels, cannonball, lures, lure release clips, sounder, and the like? Forgetting to pack a vital piece of kit is an easy mistake to make. There is nothing worse than driving for two hours to the lake and realising you have forgotten some item you can’t do without.

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