I’m really enjoying kayak fishing and after considering a bunch of non-permanent, portable finders like the FishHunter or Deeper I decided to pick up a Lowrance Mark-4 CHIRP fishfinder/chart plotter on clearance. There are a lot of expensive options for mounting the thing however I wanted to minimize the holes drilled into my precious boat while maximizing the convenience and professionalism of the installation. After scouring the internet and a few hours in 123D Design I came up with this…
Update: It was pointed out that I did not seek RailBlaza’s permission to use their star design. I’ve redesigned the Lowrance mount to connect directly to the rail.
Here are the custom 3D Printed parts:
The left two items are the scupper transducer mount. You’ll need a galvanized 5/16 hex bolt roughly 1″ shorter than your scupper depth, nut, and washer. I’m using a 3.5″ bolt which is slightly longer than it needs to be but plenty of room to spare; the design is forgiving. The nut is captured in the bottom part and the bolt is inserted through the middle with the wire running through the notches:
The scupper is then attached at the bottom. The hardware that came with the Mark-4 was slightly short for the design but it holds just fine:
The third 3D-printed part mounts the Mark-4 on any RailBlaza mount any rail. The Moken has the Unitrack system so I can adjust the location as needed:
I plan on keeping the battery in the hull and using through-hull fittings for the scupper mounted transducer and fish finder. I picked up some PG-9 cable connectors for the battery box and went with the Hobie Through-Hull Wiring Kit for the through-hull fittings. I considered using PG-9s all-around. They’re a great little design. However, I want the ability to pull off the fish finder and the Hobie kit has ‘blank’ inserts so it will be 100% water-proof with the fish finder removed. They also have a 2-wire insert so it’s only one hole for both power and transducer up front:
For the box itself I picked up a large Outdoor Products Dry Box. I had originally drilled two holes with the intention of keeping the NEMA cable in-tact however after tangling around with that extra, useless cable I changed my mine. The hole was plugged with a 1/4″ bolt, a couple fender washers and a neoprene washer… still water-tight. I clipped the NEMA cable and heat-shrinked the open end:
On the inside I wired up the fuse that came with the fish finder and stuck some packaging foam to the walls:
So now for the more agonizing part. I had a tough time deciding where to place the Hobie Through-Hull plugs. Most installations that I see tend to place the through-hull holes at the bottom of the foot wells. That makes sense as they are vertical walls that are less prone to leakage and protected against knocks on 3 sides; all sides if you count the foot pedals.
Both holes were drilled with a 1″ Forstner.
Most people will then place the transducer in the scupper directly below the holes. Unfortunately that is a pretty shallow scupper on the Moken and the transducer is more likely to scrape there. I instead routed the cable along the foot well and in the drainage channel to the under-seat scupper.
The seat is flush over the cable and stays out of the foot well pretty good. If I later decide this is a pain I can always switch to the foot well scupper with little effort.
The transducer cable is installed:
As well as the cabling for the fish finder:
The leads need to be fed into the box and the battery hooked up:
All that’s left now is to place the mount in the right position and hook everything up:
Hopefully I can per her to the test this weekend!
You can download the Lowrance mount STL from here and the transducer mount STL from here.
Did you have Railblaza permission to copy their star design?
No, I did not seek RailBlaza, Lowrance, nor Moken’s permission before designing a DIY solution for mounting my fish finder. I’m quite sure people have been shoving stuff into RailBlaza and Scotty mounts for decades… kayakers are silly with home-made hacks. I’m not sure why this would be any different.
That said, I see you are a representative of RailBlaza and one of their largest distributors. I respect Yak-Gear and use a ton of their products. I have redesigned my mount to attach directly to the rails and skip the RailBlaza portion. I will also gladly refrain from designing items compatible with RailBlaza in the future.
lilmikey, maybe you can draw a star on the side of it and get your very own bulls*** design patent.