Downrigger Selection for Effective Fishing – Salt and Freshwater Trolling

Scotty electric downrigger.
Scotty electric downrigger.

Downrigger Selection – Different Scotty Models

Deep trolling for trout in New Zealand, with the aid of a downrigger, has become popular over the past decade or so. Most anglers who fish on lakes from trailer boats in this country still don’t use them preferring to fish flat-lines instead. However, they have been around for about forty years or so, and have long been a valued fishing aid for sports anglers in other parts of the world, notably Canada and the United States. A downrigger doesn’t guarantee you will catch fish but it does add an “important string to your bow” increasing your chances of taking a fish!

Downrigger fishing has evolved a great deal in recent years as new technology has been introduced. Nowadays you can even buy a video camera that has been designed to attach to your cannonball so that even if you can’t catch a fish at least you’ll get a good look at them! There are other new systems as well, such as one that automatically raises and lowers your cannonballs to maintain the same distance from the bottom. Marine electronics have advanced to the extent that sophisticated gear is now available to suit a modest budget.

Three models from the Scotty range of downriggers. Center: The 1105 electric features a boom that extends to 48 inches for extra reach to clear your gunwale or transom and prevent the cannon ball hitting the side when conditions are a bit rough. Left: The No 1080 Scotty Strongarm which is a manual model with a strong stainless 24-inch boom, ideal for small to medium size trailer boats. Right: The Scotty Lake Troller is perfect for clamping to a tinnie or other small craft allowing you to fish deep to where the fish are cruising.
Three models from the Scotty range of downriggers. Center: The 1105 electric features a boom that extends to 48 inches for extra reach to clear your gunwale or transom and prevent the cannonball from hitting the side when conditions are a bit rough. Left: The No 1080 Scotty Strongarm which is a manual model with a strong stainless 24-inch boom, ideal for small to medium size trailer boats. Right: The Scotty Lake Troller is perfect for clamping to a tinnie or other small craft allowing you to fish deep to where the fish are cruising.

Downrigger Basics

Before we go any further let’s start with the basics. To begin with, a downrigger can only be used to troll a lure behind a boat. Therefore the first essential is a boat of some descrip­tion. The second item you need is an elec­tronic fish finder. This piece of modern electronic wizardry isn’t absolutely essen­tial, but as we’ll see later it greatly ex­pands your downrigger’s fish taking po­tential and effectiveness.

Downriggers are available in many different sizes and configurations to suit any sports fishing situation; or budget. They can be employed on any fishing ves­sel: from a modest little rowboat; a tinnie with a five-horse power outboard; all the way up to a fully-rigged deep sea charter launch after tuna and billfish! I have done a great deal of downrigger fishing from a 12-foot Porta-Bote and caught plenty of good fish while rowing. Using the oars imparts a more life-like stop-start action to the lure which, I am sure, induces more strikes than the constant speed produced by an outboard motor.

Most any species that will take a surface trolled lure will take a lure trolled with the aid of a downrigger. In New Zealand downriggers are par­ticularly well suited to fishing for rain­bow and brown trout, as well as landlocked Chinook salmon on our many lakes. We can also employ a downrigger in search of salmon off the east coast of the South Island. Downriggers have proven their worth when angling for salmon in Otago Harbour and its approaches around Taiaroa Head. Quinnat salmon have also been successfully targeted and caught off Banks Peninsula with the aid of downriggers.

Kahawai, albacore tuna, yellowfin tuna, skipjack tuna, and mako sharks have all been suc­cessfully targeted with downriggers in New Zealand. Often tuna and kahawai will be picked up on a downrigger trolled lure even though there is no action on the surface lures. At sea, downriggers have been shown at times to be by far the most effective trolling option, for the conditions and target species! Very often it is the deep lure behind the cannonball that is hit first.

The paddle wheel on the left provides a more accurate boat speed reading on your sounder when trolling at slow speeds.
The paddle wheel attached to the transom (on the left) provides a more accurate boat speed reading on your electronic sounder, especially at slow trolling speeds.


There are various ways we can troll a lure behind our boat. What are the op­tions An un-weighted line (otherwise known as fishing a flat line or Flat Lining)

An un-weighted line (otherwise known as fishing a flat line or Flat Lining)

This method is the simplest of all. We just tie our trout lure to the end of our 6 lb monofilament fish­ing line and lower the lure over the transom and let out line as our boat is travelling forward through the water. In order to avoid a huge belly in the line apply slight pressure as the lure drops back. If it’s an egg beater reel you can just pop your finger on top of the spool to retard the line a little. It is best not to back off the drag on an egg beater otherwise you will have to set it again once the lure is far enough back for your liking. This is a hassle and not a very accurate way of going about it. A free spool reel is easier to use. You can simply put the reel out of gear and thumb the spool.

The rod and reel used for flatlining can be the same light spinning outfit you would use to cast from shore. Flatlining is the easiest method to employ when we wish to fish on or near the surface. The depth of the lure will be determined by a combination of the following considerations: the type of lure, the length of the line we let out, and boat speed.

Almost all lake anglers who troll for browns, rainbows and landlocked salmon in New Zealand will have used this un-weighted line method with their Tillins Cobras and Tobys behind the boat. With light spin­ning gear and 6 lb line, fish are able to give a good account of themselves when hooked. The disadvantage of this method is that it only works well if the fish are swimming, and feeding, close to the surface. Therefore trolling a surface lure for trout is more likely to be successful when overhead conditions are gloomy, and the fish are mostly in the water layer nearest the surface. The most favourable conditions for flatlining are: early morning and evening, when there is an overcast sky, a good chop on the water, or even better if it is raining!

As I said earlier just how deep your lure will go down on a flat line is very much determined by boat speed and the type of lure employed. When trolling a Cobra or Tassie Devil on light line boat speed needs to be down to a slow walking pace or your lure will just plane straight up to the surface. Bibbed minnows will dive down the deepest.

Generally speaking the larger the bit relative to the size of the minnow the deeper it will dive for a given trolling speed. Always keep in mind your boat speed when flatlining. You only want to be doing one or two knots at most. If your lure is breaking the surface every now and again you are going much too fast.

A small paddle wheel will provide a more accurate gauge of speed to your fish finder than one of those typical levers which really only register when you get to about five knots. If you have no other way of determining boat speed lower the lure over the side and adjust your boat speed until the lure swims and dives at its best. Then maintain that speed as you let out more line for the lure to drop back. This is very important. If you arrive back at the boat ramp and discover your mates in the other boat have caught their limit while your crew remain fishless then you may well have been trolling your lures far too quickly!

Local knowledge based on years of experience fishing at different times, and under varied conditions, should never be underestimated when trolling. Lakes often fish quite differently at certain times of the year, so whatever fishing method you plan to use, cultivate the habit of asking the old hands what they recommend you try. New Zealand Fishing Flies.

Tie on a weight

It is possible to get your lure down deeper for a given boat speed by tying a lead “D” weight, or spiral leads to the line above the lure. How far above the lure the lead should depend on two factors. If the lead is too close to the lure it will completely deaden its action thus making the lure lifeless. Or at least hamper the lure’s action to some degree. The second factor is that we won’t be able to wind the lead on to our spinning rod so in order to net the fish the weight cannot be more than a rod length or so above the lure. This is also a good method – up to a point. As with the un-weighted line, it is difficult to know just how deep our lure actually is below the surface, though it is sure to be deeper than with no lead at all.

We also have to fight the fish with the weight still on the line. In order to get any depth, we need to tie on a heavy lead weight. A heavier weight, in turn, means we have to resort to a heavier line to cope with the extra weight. This creates a bit of a problem because if we tie on too much weight when we finally hook a fish it has to drag it all around and so can’t put up much of a fight. In some cases when you hook a small or undersized fish, particu­larly a trout, it can easily wind up dead before you realise it has been hooked!

Thirty-odd years ago a Jardine lead – painted green – with a coiled wire at each end, was wound on the end of the fly line just above the trace. This was pretty much the only way to get a bit of extra depth out on the lake.

Harling for Trout

Trolling a feathered lure behind our boat on a fly line with a fly rod, a method known as Harling is somewhere between a weighted and an unweighted line, that is if we are to make a distinction! Harling a smelt fly is a very relaxing and time honoured fishing method – pleasant indeed on a warm summer’s day!

There are numerous rod, reel and line combinations used for trout Harling in­cluding: fast or slow sinking fly lines, the addition of a “colour” or two of leadline, various trace lengths from 5 to 20 metres, and tying on two flies or a fly and a Co­bra, and so on.

Usually, the whole fly line is let out to­gether with plenty of backing in order to get the lure well behind the boat and away from disturbed fish. Harling is still very much a surface trolling method. Even with a very slow boat speed of un­der 2 knots, the lure will usually be less than five metres (25 feet) beneath the surface at the absolute most. For this reason, Harling works very well early in the morning, or in the late evening when there is less light on the water and trout are more likely to be feeding near the surface.

Harling is particularly effective if the boat is propelled by oars rather than a motor. This makes the feathered lure rush forward on the pull stroke and drops back as the oars are lifted from the water. The lure action is much as is would be if mending the fly line by hand. It is even better if you can talk someone else into doing the rowing! Harling from a rowed boat is a very productive fishing method for trout on smaller water. On some of the smaller lakes in New Zealand angling regulations – quite rightly – do not permit trolling with a motor. Harling will enable water to be covered where dense bush to the water’s edge would render other methods impracticable. In such situations, if the lake margins are shallow any other method would be difficult to employ, save perhaps casting from the boat towards the edges.


Lead core lines have been used for many years by trolling anglers in search of trout. Lead-line is an effective and a per­fectly legitimate fishing method.

With a lead-line you have a bit more control over lure depth in that leadline is marked with different colours metered every ten yards. It sinks at about five feet per colour and so a whole 100-metre line will get you down to about 50 feet (15 metres). Which is about the maximum fishable depth with this method.

Although getting your lure down to a predetermined depth is a bit simpler with a colour-coded lead-line it still has its limi­tations. It puts your lure down to an ap­proximate depth depending on boat speed.

Perhaps the biggest disadvantage with lead-line is that, as with a lead weight tied to the line, it deadens the fight of a fish. Many anglers, rightly or wrongly, won’t fish with lead-line for this very reason. Small fish, in particular, are unable to fight at all!

Scotty electric downrigger model mounted on the transom of a McLay trailer boat. The use of a separate battery avoids any risk of a flat boat motor battery.
Scotty electric downrigger model mounted on the transom of a McLay trailer boat. The use of a separate battery avoids any risk of a boat motor flat battery.


A downrigger consists of a robust spool onto which is wound about one hundred metres of stainless steel wire. The wire has a rated breaking strain of about 150 lb. A heavy lead “Cannonball” is clipped to the end of the wire.

Typical downrigger set up.
Typical downrigger set up.

The lure is then let out behind your boat on a completely separate rod and reel. When the lure is 30 metres out the back, the monofilament line close to the rod is clipped into a line release clip, which has been tied to a foot or so of heavy monofilament. The other end of this short length of mono is clipped to the stainless steel line just above the cannonball. The cannonball is then lowered beneath the surface of the lake down to a precisely determined depth. The exact depth is determined by a counter on the downrigger, or on a less expensive model, by counting each turn of the downrigger handle as the cannonball is played out – typically one, or two, feet per revolution. When a fish strikes the 6 lb monofilament line is pulled free from the release clip and played on the rod and reel only, com­pletely unencumbered by the cannonball.

When a fish strikes the cannonball is quickly cranked up out of the way either by turning its handle, or, if you have an electric model, by flicking a switch. The Scotty Depthpower models also feature an extremely useful “dead­man’s switch” that automatically stops the motorised re­trieve when the cannonball is just below the boat.

The downrigger system has several obvious advantages over the trolling methods mentioned earlier. There is no weight on the line so you can fish with a light line down to 4 lb if you wish. You need no specialised fishing tackle. Any light trout spinning, or fly fishing outfit can be used with your downrigger.

Unlike the other methods, we’ve talked about the depth of the lure can be determined very accurately with the aid of a line counter built into the downrigger. When a fish is taken at a particular depth, by noting the number on the line counter, we can return our lure once again to that exact depth.

A downrigger also means we can fish effectively at much greater depths than would otherwise be possible. With the benefit of an electronic fish finder we can set the cannonball depth to take best ad­vantage of: the lakes underwater con­tours; thermoclines; and fish depth.

Fishing with downriggers may sound a bit complicated, to begin with, but with a bit of practice, it is actually quite a sim­ply device to operate. I caught my first trout on Lake Brunner within an hour of starting to use it. I had no previous expe­rience with downriggers at all to that point.

Line-out indicator on a Scotty Strongarm 24.
Line-out indicator on a Scotty Strongarm 24. Used in conjunction with an electronic sounder the line-out indicator allows you to set the cannonball depth, and your lure, to exactly where the fish are holding.

Selecting a Downrigger

There are several downriggers brands available in New Zealand. However, my experience has all been on various different models manufactured by Scotty Fishing and Marine Products. This company is based in Victoria, British Co­lumbia, Canada and has been producing innovative fishing and marine products for over 50 years. The Scotty range of downriggers is extremely well built. They have had enormous sales success world­wide.

In choosing a Scotty model to suit your boat the main considerations are the size of your boat, budget, and the target species.

Many anglers use a downrigger exclu­sively for trout fishing on lakes. I would use mine for this purpose probably 95 per­cent of the time. Once you have used a downrigger a few times its operation becomes second nature.  For lake trolling especially a downrigger adds another weapon to your arsenal. I have often found that the first strike nearly always comes on the deeper set lures used with the downrigger. 

Cannonball Weight

The cannonball sinks faster in freshwa­ter than it does in salt water. If chasing brownies and rainbows is the only use you are likely to put your downrigger to you’ll only need a cannonball weighing between 3 and 5 pounds. With these lighter weights, the downrigger doesn’t need to be as big – or expensive! Fishing from a 10′ tinnie down to moderate depths of 20 metres or so a compact manually operated Laketroller such as the No.1071 Clampmount or No.1073 Bracketmount will be perfectly adequate.

At the other end of the spectrum, Scotty downriggers are available that can han­dle weights up to 20 pounds and are de­signed for deep sea and ocean trolling. These are the models used on fully rigged game boats in search of billfish and tuna. On a deep sea game boat, the top-of-the­ range electrically driven Depthpower No.s 1105 and 1100 are often employed.

The No.1105 has a 48-inch long arm, or boom, designed to prevent the cannon­ ball from swinging into the hull as it clears the water in rough sea conditions. The arm length must be sufficient to prevent this happening whatever the size of your boat. The higher your mounting point above the water the longer the arm length required. Scotty also produce 5′ and 6′ heavy wall arms available on special or­der designed for big launches!

These electric models are a joy to use both in the sea and on lakes. When a fish strikes you simply hit a button and the electric motor lifts you cannonball up out of the way so you can play your fish with­out any danger of it tangling itself around the cable. The electric models are particu­larly suited to trailer boats around 20 foot in length, though you can still use them on a smaller boat if you wish. The electric model No.1105 worked very well on the transom of my 4.3 meters (14 foot) StabiCraft.

For convenience, ease of use, and the versatility of a model that is perfectly at home either on the ocean or lake fishing, the electric model No.1105 would be the best you can get. The electric models re­ally come into their own if you are likely to be regularly lifting, and lowering, a heavyweight to maximum depths of say 200 feet. The Depthpower electrics will raise a 10 lb weight at the rate of 194 feet per minute while drawing 6 amps. It will also lift a 20 lb cannonball at a rate of 136 feet per minute drawing 12 amps. Accord­ing to Scotty these are the fastest retrieves and the lowest amp draw of any ­downrigger made.

We ran ours from a Kilwell 180A Power Station and had a 10 lb weight go­ing up and down all day on the electric model and it never looked like slowing down. The 180A Power Station is a good option for smaller boats. However, you can connect the Scotty downrigger di­rectly to your boat’s electrical system if you wish. I feel more comfortable running it from the separate Power Station because there is no chance of a flatboat battery on my 40 hp Johnson main engine, after a day trolling on my small 6 hp Johnson auxil­iary trolling motor.

The electric models are also the most expensive at around $NZ1,500.00 There is also a range of in-between, manual models available. The bigger manually operated No. 1090 Longarm 4­-48″ Telescoping Boom, and the No. 1080 Strongarm 24 – 24″ Boom, are both very robust and will do any job asked of the top of the range electrics, only more slowly. The Strongarm 24 is approxi­mately $750.00. These two models have been the preferred choice of fishermen for over twenty years. Though you have to crank the handle by hand, lifting the can­nonball is a breeze thanks to the high speed two feet per turn spool coupled with an extra leverage extension handle. They also feature the same positive lock slip clutch control which saves your gear in case of a snag on the bottom, an auto­matic brake, and deluxe Scotty line re­lease. They also have the very useful Tilt­up and locking mounting bracket which is very handy for rigging, as well as lift­ing the downrigger well clear of wharf piles when tying up!

Line counters are standard on all mod­els except the Clampmount and Bracketmount. With these two smaller Lake trollers depth is measured by count­ing the revolutions of the spool as the weight is lowered. The line counters can be calibrated so that counting starts when your cannonball touches the surface of the water.

The Scotty manual models have a low profile and so don’t get in the way when not being used, and all can be removed from your boat for storage within a cou­ple of seconds.

All models are corrosion resistant and maintenance free. You don’t have to oil or service them in any way.

Generally speaking, if you can afford it and your boat is big enough I’d go for the convenience of an electric model.

If you are happy winding the handle on a manual and you want to fish in the sea as well as freshwater, go for the Longarm or Strongarm models. If you are only going to fish in freshwater and want a manual model only, but still want to fish down to 100 feet the Depthmaster and Depthking are good choices.

If you are fishing freshwater only in a small boat (under 12 foot) the Scotty Clampmount Lake Troller and Bracketmount will al­low you to fish with cannon balls up to three pounds.

Finally, the bigger models offer the greatest flexibility in that they can be used for salt and freshwater trolling. After all, you might be in a position to get a bigger boat next year, or the year after, so a more robust model purchased now may be bet­ter value long term.


more recommended stories