How to

The Noise Factor

According to David Green, limiting the noise your boat transmits into the water can greatly improve your catch.

A FEW months back my electric motor was out of action and my mate’s son Jake was ravenously keen for a fish. We were working soft plastics chasing flathead, something I’d normally do under electric power. With no electric, we decided to anchor up and fish the likely spots by progressively moving along the flat and re-anchoring as we needed to. I didn’t have great hopes for this session, but after we set the pick in only a metre of water we began casting. The tide was running hard over the top of the flat, churning up weed and creating little tunnels of current between the weed patches. We caught a few smaller flathead to 50cm over the first 15 minutes, then we moved and re-anchored 30m away as the tide filled a bit and rolled in over the sand bank. We then started catching a lot of fish. What was really interesting was the number of fish that seemed to follow the lure and then sit under the boat. We were getting lots of bites directly under the boat in a metre of water, and there were some pretty good fish amongst them. We finished the two hour session with 33 flathead to 78cm from a spot that normally only produces six to 10. And since that day I’ve repeated the process several times.

Skinny water, spooky fish
In shallow water an electric motor will definitely spook fish. It may be a better alternative than a noisy two-stroke or even a four-stroke outboard, but the noise factor of any motor scares fish in shallow clear water. I’ve always thought the electric was the quiet alternative, but anchoring up is definitely even quieter, and means you fish the area around your boat thoroughly and well. A lot of fish follow the lures and end up parked under the anchored boat. This gives you several cracks at the one fish, and flathead, when in a lure chasing mood, will always give you repeated chances to hook them.

It is important to consider the noise your boat makes very carefully. Less is always better. When I was a kid, dropping a sinker in the bottom of the boat was a smacking offence and my pop always told me “it scared fish for miles”, so I grew up very aware of minimising noise. Well known tournament angler Ben Godfrey was recently doing some underwater filming and he reckoned the electric was extremely loud and high pitched and fish tended to stay clear of it. This is why long casts when fishing from a drifting boat under electric power are often the best method, and it is also why a lot of US flats boats are moved along with a pole. Wary fish such as tarpon, snook, bonefish and permit can all shy away from the whirr of an electric motor on the flats. Electric motors make noise and fish bugger off because of them.

We’ve now started fishing a lot more using “tactical anchoring”. This makes us really focus on the little back eddies and run offs and fish them thoroughly. The results have been outstanding on flathead, and I’ve used exactly the same tactic on barra and jacks. The fish happily swim close to the boat and there are plenty of strikes just as you lift the lure out of the water. When you catch 70cm flathead directly under the boat in 800mm of water you have to be doing something right.

Keep the noise down
Large predatory fish are inherently cautious. In the middle of winter we fish a lot in the night for mulloway and the particular spot we fish has crystal clear water. The jewies chase mullet on the top of the tide. We anchor up carefully, but this type of fishing requires absolute stealth and minimal noise. We don’t even turn on the bilge pump to fill the live bait tank. If you get the spot to yourself or with one or two like-minded careful anglers you may catch a fish. I prefer freezing cold, rainy, windy nights for one main reason. It keeps the noisy, stupid anglers away from the spot. Time and time again we see people leave the motor on, bang about, shine lights in the water and make general fools of themselves. The jewies leave if these people are about. It is the marine equivalent of deer hunting, but some people just don’t get it. These are the same anglers that reckon jewies are hard to catch!

If you are chasing cautious fish and must leave the motor running, you need to fish as far from the motor noise as you can. This means making long casts or trolling well back behind the boat. The shallower the water, the further back your lure or bait needs to be. Sometimes you just can’t be too far back. Even when fishing offshore, some species such as wahoo respond best to lures fished up to several hundred metres back. This greatly reduces the effect of boat noise in the space where the fish feeds on the lure long after the boat has passed. This is a commonly used method in South Africa, and some anglers use massively oversized reels in order to get the line capacity to troll way back in the next postcode.

Noisy boat bits
Different hulls also conduct noise differently. Aluminium tends to bang and slam and transmits noise through water much more than the sound dampening effect of plastic or fibreglass hulls. A carpeted floor in a tinny can greatly change the underwater acoustics of a boat and avoids the sharp clang of metal on metal. Aluminium is great stuff to build rugged hulls out of but transmits noise underwater far more effectively than fibreglass, and you need to take this into account when fitting out your boat.

Even out on the bluewater different engines cause different effects on fish. When trolling, a low throbbing diesel or a quiet four-stroke outboard tend to draw more strikes close to the boat than two-stroke engines do. Some experienced marlin skippers are extremely aware of the boat’s “fish attraction”, and while some hulls are known as “fishy”, some others just don’t raise marlin into the spread as well as others. The Cairns marlin fleet in particular is very aware of which boat is “fishy” and some well known boats in the fleet have fantastic reputations as fish catchers,  reputations forged over many seasons. And while these reputations are due to a lot more than the boat itself, the skippers are very aware of those “magic” hulls that make the right marlin noises.

Sounder noise is another aspect of boats that has been discussed a lot. Some fish, particularly in hard fished waters, are very shy of the pings of echo sounders. Snapper and pearl perch in particular tend to move away when the sounder noise starts. And the bigger and more powerful the sounder, the more noise it makes. So if you aren’t actively using your echo sounder, turn it off. You might just catch a few more fish.

The take home message is to never forget how noisy you are on the water. We tend to take things like electric motors, sounders, bilge pumps and engine noise for granted, but never forget that water transmits sound much more effectively than air. And the less noise you make, the more fish you will catch.

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