My thoughts on electronic "Fish-finders"
by Ross C.
These days it seems that nearly every new powerboat is supplied with a Sonar Fish-finder, GPS, plus electronic mapping and other gadgets. There are even portable Fish-finders available that land based fishermen can use to cast a sonar detector into an area where they wish to see the bottom and any fish profiles are transmitted by radio waves back to the shore base station or a wristwatch style receiver and screen.
A portable Sounder attached by
bungee cords to the deck-lines
For the first twelve months of Kayak Fishing I refused to buy a Fish-finder as I felt it would be cheating to search for fish on a sonar before even starting to fish for them. A major part of my fishing enjoyment has always been in the art of tactical selection of likely spots without ever really being sure there are actually fish present. If I caught a fish or two it made the hunt worthwhile and if I didn't catch any I could go away thinking that there just may have been that big one there and whilst he didn't take my bait on one day he might be interested in it next visit. I therefore thought a Fish-finder would ruin the anticipation, as I'd know as soon as I arrived at my favourite spot if no fish were present, and then I'd probably spend more time "fish-finding" instead of fishing. After all, "fishing" didn't necessarily require fish to be caught or even to be present. It was the planning and preparation, the hunting, the expectation, the successes, the failures, the healthy exercise, and the opportunity to relax in interesting locations that gave me enjoyment. To catch a few fish was a welcome bonus and to know that I'd worked out all the strategy by myself made it even more rewarding.
Kayak Fishing had offered me the chance to experience a simpler and more natural way of fishing and I reckoned to go and load up my Kayak with electronic fish-finding gadgetry would be a travesty to the minimalist principles of my newly found sport.
This philosophy was fine for estuary species in my local saltwater rivers as structure, snags, sandbanks, mangroves and drains were easy to see, but in my local freshwater lake I soon found that it was a completely different story.
Try as I might I just couldn't catch fish in the impoundment and after half a dozen trips of unsuccessfully trolling around points, rock walls and steep banks or casting around snags, weed-banks, rivulets, and submerged trees, I realised that I was doing something wrong.
After swallowing my pride and asking a couple of locals as well as reading a few freshwater fishing magazine articles I learned that the biggest fish in the large stocked impoundments had developed new feeding habits whereby they followed the schools of naturally reproducing bait fish to get an easy meal by picking them off from below or beside the school.
As these bait fish school in deep water in the middle of the lakes this is where the Bass and other predators could be found. Because, at the surface, such territory is featureless, a sounder is essential to locate these schools of baitfish and the attendant larger fish that I want to catch.
I rationalised that, as the Bass, Golden Perch and Cod were not naturally occurring in the local freshwater lake I fished that, for this situation, using a sounder was not such a bad thing after all. I was further able to justify the need for a sounder based on the fact that even the Eskimos had devised a primitive type of stethoscope to locate seal and walrus movements below the ice.
Once I got over this change in my philosophy I ordered a portable Fish-finder that utilised a suction cup to attach the transducer to the hull and could therefore be easily installed after launching and quickly removed prior to transporting the Kayak.
Whilst I wanted a light and portable unit self-powered by dry-cell batteries, I didn't buy the most basic unit around and, instead, spent a little more to have more resolution on the screen and more transducer power. I ended up getting a 240 by 160 pixel screen and a 250 Watts (RMS) 2000 Watts (Peak-to-Peak) transducer with power coming from two 6V lantern type batteries that gives up to 40 hours of operation per set.
Transducer attached by suction cup
with circles showing mounting points
The transducer has a 24° cone which means the diameter of the cone is 4.2 feet per 10 feet of depth.
| Depth (ft) | Cone diam. (ft) |
|---|---|
| 10 | 4.2 |
| 20 | 8.4 |
| 30 | 12.6 |
| 40 | 16.8 |
| 50 | 21 |
As the standard transducer fitting that came with the unit was designed for mounting on the transom of a boat I therefore had to make a small plastic fitting to insert between the transducer and the supplied mounting bracket. This fitting now enables the suction cup to be attached to the side of my Kayak and allows the transducer to be facing forward which is essential for correct operation while moving.
Transducer looking
from the stern
So that I can correctly locate the suction cup on the side of my craft I drew two circles on the side in permanent marker with one circle for vertical sounding and the other for those rare occasions when I want the sonar beam to angle a bit to one side.
The mounting locations were chosen to ensure that the transducer was not deeper than the draught of the hull (to avoid scraping it on the bottom) and that the mounting position did not get in the way of my paddle stroke.
To further reduce potential for damage I attach the transducer after launching and remove it before landing.
The drag from the transducer attachment slows the Kayak a little and is quite noisy when paddling fast due to turbulence created on the starboard side however at slow trolling speeds I don't even notice that it is there. If I am not trolling I usually remove the transducer while paddling and re-attach it at the next trolling area.
When using the sounder in very weedy conditions it is necessary to occasionally reach down and clear strands of weed off the attachment bracket.
I now use this Fish-finder whenever I go fishing in deep freshwater lakes but I still don't take it when I visit saltwater rivers and creeks.
Fish holding at
edge of riverbed
Jig being lifted
and dropped
It took me a while to work out what I was seeing but now I find the Fish-finder invaluable in deep lakes and, as I paddle, my eyes are constantly on the screen looking at what structure is underneath me, what depth the water is, and at what depth the fish are holding. Once I find an old riverbed it is quite easy to stay in the deep water by slightly turning the opposite way every time the water depth starts rapidly decreasing. This results in a zigzag course but lets me know where the riverbed lies and roughly how wide it is so that I can plan my trolling runs.
When the Fish-finder is aboard I have to re-arrange my storage area accordingly and the bum-bag that normally sits on the deck has to slip beside my seat on the floor of the Kayak. This makes it slightly less convenient to open it however this doesn't affect my level of comfort while seated.
In conclusion, the purchase of a Sounder has really increased my level of success and enjoyment when fishing the expansive stocked freshwater lakes that we are so fortunate to have in South East Queensland.