You spend a lot of money on your boat, fuel, and fishing tackle. With the general decline in fish stocks, and competition from professionals and other recreational anglers you need to use technology to increase your strike rate. Putting your bait or lure in the strike zone will maximize your results.
Fish move up and down in the water column during the day, depending on a variety of factors: depth at which bait is holding, thermo clines, strength of sunlight, and (increasingly, near big cities), frequency of boat traffic. Scientific studies using sonar tags on marlin, tuna, and sharks show that game fish spend only a part of the day on the surface. Trolling lures on the surface while fish are down a hundred feet or more is a waste of your time and fuel. By using a downrigger, in combination with a sounder, you can match your bait or lure to the depth at which fish are showing.
Here's a few tips on buying and using downriggers:
1 get a downrigger that's easy to use, and mount it somewhere that's very accessible. If your downrigger is easy to use, you'll adjust the depth and check your bait more often, remembering that the line must be wound up at the same time as the downrigger weight, otherwise you can get tangles. Most anglers are right handed and most fishing reels have their handles on the right-hand side, so it's best to buy a downrigger with the handle on the left hand side. Then, the downrigger can be wound up with the left hand, and the reel with the right hand. Don't buy a downrigger on price alone, get the best one you can afford. A quality model will be easier to use, and it should be easy to adjust depth, check your bait condition, or whatever. if a good fish or bait ball shows up at the leading edge of your sounder screen, you need to be able to quickly adjust your lure or bait to the correct depth. When you have a downrigger that's quick to adjust, you'll find it's common to see a fish on your screen, then take a strike as the bait or lure passes its position. if you decide to upgrade or sell your downrigger there's a good second-hand market for them, on eBay and elsewhere.
2 Cannonball type downrigger weights have a large frontal area, which offers resistance to the water. They also roll around when placed on the deck, and are harder to store. A pancake style weight is better. These have a narrow profile, which give a lot less resistance, and their tail fin can be bent to move the weight left or right of the wake. In a boat with a narrow transom this will give you more room to manoeuver. In a game boat with a wide transom this will allow plenty of room to run flat lines. On both big and small boats a narrow profile weight will decrease resistance and, depending on your sounder's cone angle, help to bring the weight onto your fish finder screen. This is helpful in adjusting your lure or bait depth to the depth at which fish are showing on the screen. Pancake weights can be stored flat, anywhere that suits.
3 electric downriggers offer a quantum leap over manual versions. I've fished on many boats fitted with manual downriggers where we've trolled over good bottom structure where fish are holding without a strike, then subsequently found we'd been trolling a hook with no live bait attached while we passed over a good strike zone. It's human nature not to want to laboriously crank up a manual downrigger, maybe from a hundred feet or more, just to check the bait's okay. But with electric downriggers, the only effort required is the flick of a switch. By flicking that switch to 'up' you can check that your live bait is still swimming strongly *before* you approach good structure. Where an electric downrigger really comes into its own is when a big fish hits. Whether it's a bass heading for the snags, a kingie or GT charging for the bommie, or a marlin emptying your spool, you only have to pay attention to fighting the fish. Flick the 'up' switch and your weight will rise at 190 feet per minute (Vector downriggers.) You don't have to worry about cranking the weight up or the fish running around your downrigger cable.
4 after trying all kinds of releases, we have gone back to rubber bands. They hold the line firmly without damaging it, are quick to apply, don't have the water resistance of the larger commercial releases, and give a clean release on strike. A thousand can be bought for a few bucks from Office works, or the post office. However, you must use the correct size rubber band. We recommend a size 16 rubber band for most saltwater applications (see Step 7, in our step-by-step pictorial.)
5 for downrigging mid-size live baits like slimy mackerel, yellowtail, garfish or herring you need everything ready, so that the bait goes from the tank to the water as quickly as possible. Have the downrigger weight over the side with a short leader (maybe, 2 feet) going from the weight to a snap swivel, with the clip open. Have the rod you're going to use in its holder, with the ratchet on and in free spool, or with a light drag, or with the bait runner mechanism applied. The boat should be moving forward slowly. Lay out a small wet towel (around 6 x 6 inches), the bait tank net, and an open eyed bait needle, with a rubber band already in place on the needle. Catch the bait fish fast, and transfer from the net to the wet towel with a firm grip just behind the gills. Push the bait needle through the nose, release the needle, grab it again on the sharp end and draw it through so that there are two rubber band loops of equal length either side of the nose. Grab those two loops between index finger and thumb, and pick up the hook with your other hand. Drop the loops over the gape ,then twist 2-3 times and bring the hook back through the loops. Put the bait over the side and feed it back, watching to ensure it's swimming properly. Let out whatever amount of line you require (depending on depth, conditions, species etc) and grab another rubber band. (I keep 5 or 6 around my wrist when downrigging.) Hold this band perpendicular to the line, and twist the top loop 2-3 times around the line one way, and the bottom loop 2-3 times around the line the other way. Check the rubber band is holding the line without slipping, take the two loop ends, and put them into the snap swivel clip. Close the clip. Lower the weight to whatever depth is required. The line should come off the rod smoothly as the weight sinks. Adjust your drag setting, and you're set to go. Sounds a bit complicated, but after practice your baits will go from the tank to ten metres down in well under a minute. This method has worked for us on everything from tailor to marlin.