PHOTOS of Somerset Dam's big bass always create interest. Even in an angler's hands and out of its natural element, a Somerset bass is a powerful fish. Yet Somerset can be a hard taskmaster for the beginner flyfisher, with lucky casts a non-event due to the depth at which the fish are feeding.

Deep fly bass fishing isn’t like any other style of bass fishing. With lures, soft plastics, ice jigs, spinnerbaits, beetle spins, tailspinners, or whatever, the offering can be cast a country mile from the boat and can then be relied upon to sink rapidly. With the deep fly it's a different ball game. The fly line takes the fly down to where the fish are and once the fly is down there everything needs to be done right or there’ll be nothing to show after a session but casting practice.

If I had to nominate clues to success with the deep fly, most would revolve around the sounder. I rely on my Lowrance X75 sounder in my own boat to show me fish, and once I see the telltale lines or big fat arches across the lower section of the screen I believe implicitly in what I'm seeing and fish as hard as possible until a fly connects.

On the subject of sounders, my wife Denise has a Lowrance X29 – a far less expensive unit than the brilliant X75 – which we use in her tinny. We carry the unit attached to a board and pop a suction cap type transducer on the transom when using the little boat in shallow or tree-studded waters. By way of change we opted to take the tinny to Somerset Dam for a snappy morning session recently, and used the X29 unit to great effect.

My point is this: if you cannot afford a top shelf sounder, simply lower the sights and rely on the less expensive one. Once you have faith in your sounder, deep fly fishing becomes far more productive.

Whatever sounder we are using, our procedure is the same: unless I luck on a school straight away (and this has happened a few times in the past), I slowly travel across the drop-off areas to locate fish. I haven't seen a South Queensland dam yet that doesn’t have a river bed or creek bed that can't be tracked on a sounder.

Once I’ve found the deep water I travel very slowly in a criss-cross pattern, moving from one side of the feature to the other. The idea is to look closely at the area just prior to the drop and, while careful searching may take up some time, sooner or later you’ll see the thick spaghetti-like lines or a series of fat arches indicating a school of feeding bass. Then it's time to drop a marker on the school.

To my way of thinking, a GPS reading is fine for later reference but a marker buoy is a far better ‘real time’ reference point. A marker buoy allows you to move to either side of it to see where a school seems to be more concentrated or perhaps to where it is moving.

To allow the fly to sink to the level of the fish, I highly recommend Striper IV fast sinking fly line. Make a long cast, putting the fly as far away from you as possible. A bit of boat drift doesn’t hurt at this time and windy days can be an asset. Next, allow time for the fly to sink (usually four seconds per metre of sink with the Striper) and once the correct time has passed in relation to the depth (I count down on every single cast), retrieve your fly.

You retrieve rate should vary with what you’re seeing on the sounder screen. If the bass look to be really active, judging by the way the tracks of the moving fish are criss-crossing or moving up or down on the screen, work the fly in short, snappy strips of around 30cm or so with a three second pause between each stripping movement.

If the fish are feeding closer to the bottom, with fish in up to 15 metres of water, the idea is to retrieve the fly in a slower draw. In this case, a slow draw of 40 to 50cm will usually tempt a bass to have a go.

The thing to understand is that when you’re fishing at 10-15m (the depth I commonly fish for schooled bass) the 'bite' will feel more like that of a 20cm whiting than a 50cm bass. While a lot of fish will simply take hold like a stump on the move, many others will nibble or tweak the fly. These fish are certainly interested and worth persevering with by throwing a metre or two of slack line back at the fish and waiting a few seconds for it to straighten out. A couple of snappy retrieve movements should allow you to see whether the fish will have another go. Most times they will!

The choice of fly for this style of fishing is pretty universal. John Schofield's Bass Vampires and Boneheads have won John a lot of competition points and it's hard to go past these flies, which he has very generously introduced to fly anglers everywhere. I have also had success with large white rabbit fur flies when populations of bony bream are prolific, which includes both the Wivenhoe and Somerset dam, as well as the water-deprived Moogerah Dam.

I consider this method of locating fish to be standard, as is the tackle used to take them, but I believe there’s still a lot to be gained by experimenting with different flies. How deep can we hook a bass on the fly? On a recent excursion to Somerset Dam my fishing mate Richard Harvey hooked up on a bass with the X75 showing a depth of 25m. Now that's deep fly fishing!

1) The author with a brace of fat bass from Somerset Dam.

2) Bass like this are what make Somerset Dam a Mecca for flyfishing bass fanatics.