Why Your Trolling Lure Won't Dive or Swim Straight

A diving lure that rolls over or keeps coming to the surface is not doing the job you bought it for. Before paying out another fifty metres of line, find out whether you have a depth problem, a speed problem or a lure that is no longer swimming properly.

The quickest useful test is close enough to see the lure, in clear water away from the propeller and other lines. Start slowly. Watch what changes as you bring it up to the speed you intend to fish. Keep loose hooks out of hands and clothing, and never lean out of a moving boat to reach a lure.

Start with the lure you actually have

A long minnow is not automatically a deep diver. Compare the two small lips below with the much larger bib in the opening photograph. Body length alone tells you very little about the depth the lure will reach.

Look for the model, size, bib version and buoyancy information on the lure or its packaging. Photograph those details before throwing the packet away. A floating, suspending and sinking version can look very similar in a tackle box, but they are not interchangeable when you pause or slow the boat.

Treat a depth marking as the starting point for checking the maker's instructions, not a live depth reading. The lures below carry different markings on their bibs. That is more useful than choosing solely by colour, but the mark does not tell you what line or trolling conditions produced the stated depth.

Separate a depth problem from a swimming problem

Watch for three different symptoms:

• It swims cleanly but too shallow. Check that you chose the appropriate diving version. Then compare your line, distance behind the boat and speed with the manufacturer's recommendations.
• It pulls persistently to one side. Retrieve it and inspect the attachment, hooks and bib before considering any tuning.
• It swims properly at low speed, then rolls or breaks the surface. Reduce speed and repeat the test. Do not assume every diving lure belongs in a fast offshore spread.

Predatek's depth explanation identifies bib design, buoyancy, hardware, speed, line diameter and line length as interacting factors. Thinner line generally creates less resistance, while excessively heavy terminal tackle can alter the action. More speed can help within the lure's working range, but too much can make it blow out. Extra line also reaches a point of diminishing returns. None of those adjustments can turn the wrong lure into the right one.

For a useful comparison, change one thing at a time. Keep a short note of the lure, line, leader, distance and speed. If you change all five at once, you will not know which change helped.

Check the connection before reaching for pliers

Make sure the line is attached to the intended tow point and that the connection can move freely. Check for a hook caught over the leader, weed on a treble or a snap jammed against the bib. A lure that suddenly stops working after a cast or missed strike deserves this simple inspection first.

Follow the maker's attachment advice. Predatek explains why bulky clips can restrict a small lure, and distinguishes tying to a fitted split ring from tying directly to an eye. Do not add a large swivel merely because there is room for one. Use sound components of an appropriate strength without loading the nose with unnecessary hardware.

Changing hooks is another change to the complete lure, not just its sharp end. Check that replacements clear the body and each other, then test the lure again. The replacement lure hook guide covers fit, ring closure and the post-change swim test. A package labelled suspending describes the intended configuration; it does not promise identical behaviour after you change the fittings.

When tuning is appropriate

Only adjust a tow point when the manufacturer permits it. On suitable conventional lures, tuning uses very small corrections followed by another swim test. Predatek's tuning instructions describe correcting the tow point toward the direction you want the lure to track. Large bends can overshoot the correction or damage the fitting.

That is not a universal instruction to bend every lure eye. Some designs have specialised moving tow points, including Nomad's Autotune system. Read the instructions for that exact lure. A cracked bib, loose attachment or damaged body needs repair or replacement, not an improvised bend to hide the fault.

A home-made lure makes the relationship between bib, body and tow point particularly clear. The worn finish in this example does not establish that it swims badly, or that it needs tuning. Test the behaviour rather than judging performance by paintwork alone.

Line out is not the same as depth down

A line counter helps repeat a distance behind the boat. It does not measure a free-swimming lure's depth. Write down the successful setting so you can repeat it with the same outfit; do not read forty metres on the counter and call that forty metres deep.

If you need controlled depth with a separate weight, that is a different setup. See the Downrigger page. If you are towing a dead bait in a swimming head, use the Head Start rigging guide; a crooked bait requires a different inspection from a moulded hardbody.

Before the next long trolling run, give the lure one short, visible test. Correct model, clean attachment, free hooks and a stable action are a better starting point than simply letting out more line.