Fishfinder for a Kayak: Installation Tips

Jerry Collins is a busy man come kayak fishing season. As the owner of Captain Kayak ((631) 750-3587) in Sayville, NY, he installs hundreds of fishfinders on his customers’ kayaks every year. Most of his customers are inshore saltwater anglers, so most fish from Hobies. The video above demonstrates how he installs a fishfinder for a kayak. We’ve compressed the steps into a clip that’s just over five minutes long. Check the bottom of this post for more detailed instructions on how to install a fishfinder for a kayak.

NOTE: Hobie kayaks come with transducer mounts built into the main scupper below the seat. The installation steps in this video are specific to boats with this feature. For instructions on how to mount a transducer on a kayak without a transducer-ready scupper, follow the link to this video.

Do you need a fishfinder or chartplotter on your kayak? It depends on how serious you are about catching fish. I started fishing with one two seasons ago and saw my catch rate triple overnight. The chartplotter function on my Lowrance Elite HD unit lets me duplicate drifts and record structure to visit later. The fishfinder helps me find bait and target suspended schools of fish. If you’re going to spend money on a fishfinder, get one that combines both these features.

Tools:

Power drill
1/8-inch, 5/32-inch, and 1-inch bits
3/8-inch socket wrench
Screwdriver
Wire stripper
Soldering iron
Heat gun or hair dryer

Materials:

Hobie Fishfinder Install Kit III
Lowrance Fishfinder/Chartplotter
Yak Attack Gear Trac
RAM Full-size fishfinder mount
Spare Hobie through-hull fitting
1/4-inch and 1/8-inch heat-shrink tubing
Solder
Zip ties
Electrical tape
Dielectric grease

Step 1: Install Yak Attack Gear Trac
– Drill a hole using the 1/8-inch bit.
– Position Gear Trac over hole and tighten first screw.
– Drill second hole on the opposite corner. Tighten second screw.
– Drill remaining two holes using 5/32-inch bit.
– Screw in bolts.
— TIP: All holes drilled are smaller than the screws or bolts. When the threads bite into the plastic they’ll form a waterproof seal.
– Reach in through front hatch. Slide washers onto bolts. Hand tighten nuts, then tighten both completely with a socket wrench.
— TIP: It helps to have a buddy use a screwdriver to keep the bolts from turning as you tighten the nuts.

Step 2: Install Transducer
– Remove seat.
– Flip boat upside down.
– Remove Lowrance-ready transducer plate.
– Thread transducer wire through scupper.
– Attach transducer to bracket (hardware comes in bag with Hobie owner’s manual)
– TIP: Leave some space between transducer and bracket so that the unit functions properly.
– Screw plate into hull.

Step 3: Run Transducer Cable Into Hull
– Flip boat right-side up.
— TIP: It’s easier to do this step if your boat is flipped on its side.
– Open hatch in front of seat area.
– Remove foam floatation blocks.
– Reach through hatch to remove through-hull fitting by twisting off the fitting nut and popping the fitting out of the hole.
– Place rubber O-ring over hole.
– Thread transducer cable down through O-ring and hole.
– Pull cable out through hatch until tight.
– Pop rubber gasket out of through-hull fitting. Pop it onto cable.
– If gasket doesn’t fit cable, select one that does from the gasket tree found in your Hobie owner’s manual bag.
– Pop the right gasket onto your transducer cable, then use a screwdriver to push the gasket into through-hull fitting.
– Push through-hull fitting into hole.
– Slide through-hull fitting nut over and up cable.
– Reach through hatch and twist nut until tight.
– Replace foam floatation blocks.

Step 4: Install Two Through-Hull Fittings In Front of Gear Trac
– First hole is for the transducer cable.
– Second hole is for the power cable, which runs to the battery
– Drill two 1-inch holes 1 inch apart through the hull in front of the Gear Trac.
– TIP: Reach through the front hatch while drilling to hold your rudder cables away from drill area. You don’t want to cut those cables with the bit.
– Clean the loose plastic from the holes with a razor blade
– Slide a through-hull fitting nut over the transducer cable.
– Reach through the hatch to thread the cable up through the hole.
– Slide a rubber O-ring over the transducer cable and place on top of the hole.
– Pop the through-hull fitting gasket onto the cable.
– Pop the gasket into the through-hull fitting and push it tight with a screwdriver.
– Push the fitting down into the hole.
– Reach up through the hatch to tighten the nut onto the fitting.
– Pull the remaining transducer cable toward the front hatch and secure it with zip ties.
– TIP: NEVER cut a transducer cable to fit the length you’re working with. Cut transducer cable does not function.
– Repeat this process for the power cable. Use a two-hole gasket for your through-hull fitting if your power cable has dual wires.

Step 5: Prepare Power Cables And Battery Wires
– Lowrance units come with dual power cables. You’ll be connecting the one with exposed red/black/ground wires.
– Wrap the end of the other (NMEA) cable with electrical tape and secure it out of your way.
– Remove the battery wiring and in-line fuse from your Hobie Fishfinder Install Kit III.
– Tie wires around mast post, leaving 15-20 inches between post and battery connector.
– Measure other end of wire from post to Lowrance power cable.
– Cut off extra wire.
– Measure the positive (red) lead on the battery wire against the in-line fuse leads.
– Cut this lead out of the wire. You’ll replace it with the in-line fuse.

Step 6: Solder and Shrink-Wrap The Wires
– TIP: Soldering is not necessary, but makes for much more secure and reliable connections.
– Slide 1/4-inch shrink tubing over the Lowrance unit’s power cable.
– Snip off ground wire.
– Strip plastic from positive (red) and negative (black) power cable leads.
– Strip plastic from the leads on either end of the in-line fuse.
– Slide 1/8-inch shrink tube over one of these fuse leads.
– Join fuse wire to positive lead on power cable.
– Slide 1/8-inch shrink tube over positive lead on battery wire.
– Join positive lead on battery wire to other fuse lead.
– Slide 1/8-inch shrink tube over negative lead on battery wire.
– Join negative lead on battery wire to negative lead on power cable.
– Solder all connections.
– Slide all 1/8-inch shrink tubing over soldered connections.
– Shrink the tubing with a heat gun or blow dryer.
– Slide 1/4-inch shrink tubing over both 1/8-inch connections on the power cable end and shrink it down to secure everything in place.

Step 7: Attach Battery Holder To Mast Post
– TIP: Make sure to slot the wiring that leads to your fuse into the grooves on the back of the screw mount. When you tighten the bracket this will keep the fuse up off the bottom of the hull, where it’s less likely to get wet and corroded.

Step 8: Apply Dielectric Grease To Fuse

Step 9: Clean Up Your Wires
– Bundle loose wires and cables with zip ties, then secure them to the mast post.

Step 10: Connect Battery

Step 11: Attach RAM Fishfinder Mount to Fishfinder

Step 12: Connect Unit to Battery, Then Turn On Display!