This article outlines how to fit the Garmin 90 fishfinder to an Ocean Kayak Prowler 13. The information within the article can easily be utilised to fit any brand of fishfinder to any fishing kayak on the market. the type and size of the fishfinder you are installing will influence the design of the installation. recent ocean kayaks are designed to accomadate a hummingbird fishfinder so do not need to have the transducer through hull.

note: the Garmin Fishfinders have a premoulded plug which is 30mm dia, this require a 30mm hole in the kayak, the hole could be filled with a sealant but a much more professional finish is obtained by using a marine cable Gland (thingy) the one illustrated is from index marine. and gives the added anvantage of being able to remove the cable and still have a watertight kayak . a touch exspensive but a nice profesional finish.

Whats Required ?

  • A fishfinder
  • 12v  battery (3.3 – 12 ah depending on fishfinder)
  • A kayak
  • A Drill, drill bits, and holecutters.
  • Screwdriver
  • Sikaflex adhesive
  • Plastic box for battery & plastic cable gland
  • Sticky back Velcro
  • A marine cable gland assembly (thingy)

Step1 – Fit the Cable Gland & pass transducer wires through.

Place the marine cable gland on the kayak at the place you wish to pass the transducer cables through into the hull.


Drill a hole for the transducer and wires to go through, using a 30mm hole cutter.



Fasten down the cable gland with 3 stainless steel self tappers (pre drill the holes for the screws). the gland comes with a neoprene gasket, you could apply some sykeflex or similar instead.


Pass the plug & cables through the gland.


Pass the cables through the top part of the Gland, the rubber insert needs to be drilled & cut according to the instructions to acomadate the cables, pull through sufficient cable to reach the fishfinder position.fitting-a-fishfinder-010

Secure the top part of the Gland using the supplied screws, the rubber forms a watertight seal as it is tightened.


Step 2 – Fit the fishfinder screen  to the kayak.

pre drill pilot holes & secure using SS self tappers, sykeflex to provide extra waterproofing.



Step 3 – Fit the transducer

Dry the hull of the kayak, then sand the kayak and the transducer. Next add the sikaflex adhesive and stick the transducer to the inside of the hull gaining access through the front hatch. ensure no air bubbles & apply pressure until set. Be aware that the adhesive takes several hours to set so dont move the kayak before this time has passed.



Step 4 – Fit the battery

The power cable is entered into the battery box using a plastic cable gland that can be obtained from B&Q or similar. drill hole to suit using hole cutter, pass enough cable through to allow connection to battery & tighten gland. fit suitable crimp on spade connectors for connecting to battery.

the battery can be made a snug fit in the box using some polystyrene packing or similar.

Fit the sticky back velcro to the inside of the kayak and to the battery box.



Stick the battery box to the velcro pad inside the kayak hatch. Connect up all the wires and your fishfinder is ready to use.

tidy the spare cable into a neet bundle and tywrap, a stick on type will keep the cable out of the way

Please be aware that fitting a fishfinder involves drilling holes in your kayak. We can not accept any responsibility for any damage caused to your kayak.

Article Kindly Written By Dave Adamson (Aka SpawneyBass).