Fitting A Kayak Fishfinder

Whitby Sea Anglers » Kayak Fishing » Pimp My Kayak » Fitting A Kayak Fishfinder

Fitting A Kayak Fishfinder

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).

By | 2018-03-23T08:50:58+00:00 May 18th, 2011|Pimp My Kayak|11 Comments

About the Author:


  1. Batman Bish May 20, 2009 at 11:49 am - Reply

    Just what I needed. I’ve been holding off doing mine as I was unsure of what to do. I read this and got the job done this morning. Thanks Dave for clear concise instructions.

  2. Filthy Rich May 20, 2009 at 11:54 am - Reply

    I thought the newer Ocean Kayaks Prowler 13 had a recess in the hull for a fishfinder transducer ?

  3. Dave September 3, 2009 at 11:53 am - Reply

    Couple of questions…
    1. Does the transducer not need to be in the water, does it work just stuck to the innerside of the bottom of the kayak as shown?
    2. Can anyone recommend a battery (rechargeable) to suit a gramin 140

  4. admin September 3, 2009 at 12:27 pm - Reply

    Hi Dave,

    No the transducer doesnt need to be in the water, its quite ok for it to be stuck to the bottem of the inside hull. Check out the Yeuasa batteries at Maplins or even Maplins own 12 volt sealed lead acid batteries. If you have any more questions please do not hesitate toi log into our forums at the link below. The lads will be more than happy to help you out :

    Alternatively just select forum from the menu at the top of this page.

  5. Graham November 8, 2009 at 9:43 am - Reply

    Hi There

    Just about to fit a fish finder to my sit on top and have been to almost every website / you tube video to gain tips and pit falls. Would love to have been able to see the pictures of your fitting as A PICTURE IS WORTH etc. My main concern is that nearly all USA fittings use marine GOOP which is not available here unless special order via E Bay from Stateside. Devcon has also been suggested but worried about heat build up when curing. Any suggestions please.
    Kind Regards.

  6. Dave Adamson November 9, 2009 at 9:26 am - Reply

    sikaflex, available from all chandlers & online

    If you dont want to stick your transducer to the hull fix a container into the kayak with a hole in the bottom, place the transducer in it & melt some vasaline which you pour in and allow to set. apperently this works very well & you can remove the transducer without damage if required

  7. Graham November 9, 2009 at 11:38 am - Reply

    Hello Dave

    Very many thanks for opening the pictures. Now having seen these, the process has become very much clearer and straightforward. I will follow your procedure and fit mine in the same manner. I was not sure if using the white sikaflex 291 would work but from your efforts it clearly does.
    Thanks again

  8. admin November 9, 2009 at 7:33 pm - Reply

    Hi Graham,

    Sorry about the pictures. I recently updated the site and forgot to put them back on show. Please could you do us a favour and if anyone ever asks how you fitted your fishfinder, could you point them in the direction of our site.

  9. Lozz November 9, 2009 at 7:55 pm - Reply

    Most silicon/pu adhisive sealant will do the job it must be adhisive sealent though not bathroom sealer.sikaflex ,adflex,soundaflex are all very good polyurothane sealers.the best way to apply it is to cut the end of the tube off and apply a big dollop as this way no air bubbles get in.key the area where the transducer is going to be placed and clean with meths or isopropol alchohol.for a more permanet fixture the transducer can also be epoxyed in using 2 pack slow cure epoxy.with ether method i put a 2lb lead weight on top of the transducer till the sealent or epoxy has cured

  10. Graham June 18, 2011 at 7:02 pm - Reply

    Wasn’t sure about how the cable gland work, but this illustrates it perfectly. Many thanks for taking the time to post.

  11. Al November 11, 2011 at 6:02 pm - Reply

    Thanks, I have been looking to see if I can fit a Garmin ‘transom’ transducer in the hull of a GRP sailing boat, your excellent pics answer the question, and what an easy installation. Great stuff!

Leave A Comment