In Hull Transducer Mounting

I am going to get my FF set up for use on my Adventure copying photos and descriptions on this site. Picked up $2.17 in parts at the hardware store and started on it already.

My question pertains to the in hull transducer mounting location. I have read suggestions to mount it in front of the mirage drive because of the bubbles generated by the fins. Because this location is the only place you can really store anything of any size should the need arise I would like opinions on mounting it under the rear end of the tank well in the center of the hull. This location is about five and a half feet from the rear of the mirage drive. This location seems ideal since you likely would not be storing anything in this location due to limited access, rudder lines, etc.

Any opinions?

Joe,

I installed a Lowrance M68c GPS/Fishfinder on my Outback kayak before accessing this forum and learning where I shouldn't mount the transducer.
I epoxied mine to the hull directly behind the Mirage drive and have experienced no interference from the drive whether I am still or pedalling at top speed with my turbo fins. I am very pleased with the Lowrance unit.

I mounted the unit just forward of the starboard lifting handle using a ram mount and a waterproof through-wall fitting for the wires. I bought a watertight boxed Coleman car starter battery to power it that I place under the forward hatch. It is overkill for battery power but I also intend to add a powered bait box and a white all-round light for night fishing. The Lowrance is easily removable and the mount does not interfere with cartop kayak carrying (I actually put the kayak on top of my golfcart to get to the beach).

So far I have used my fishfinder in depths of 3 to 60 feet and have been very pleased with it as well as the transducer mounting location. I have been surprised how easy it is to see the unit even in the brightest sun light.

Hope this helps,

Thanks Bernie. Glad to hear the transducer location worked out for you. What is a waterproof through wall fitting? I had my Humminbird FF set up on my paddle yak with the transducer set up through one of the forward scupper holes for an in water reading. I have two Scotty flush mounts that rod holders fit into on that yak. I ran my battery wire through one of those flush mounts from the battery in the hull to the FF on deck. My FF was set up into the other flush mount. Was going to put another flush mount into the forward wall in the cockpit to run the battery and transducer wires through but would like to hear about your waterproof fitting to see what that is.

I want to get the Hobie bait tank when those are available and I understand they come with a battery or at least a place to mount the battery. Others have said that a FF and bait tank on the same battery cause interference with the FF. I do not know this first hand however.

Hi Joe,

I bought the waterproof fitting at West Marine. It consists of a rubber plug with a top retaining ring and a bottom plate. You drill holes in the rubber plug the size of your wires and then put a slit in one side to slip your wires into the rubber plug. When you screw the retaining ring on the outside of the hull, into the bottom plate inside the hull with three screws, it compresses the rubber plug slightly to ensure that the wire penetrations are watertight. They offer several sizes of these waterproof wall penetrations at West Marine. I used the smallest they had.

I'll take and post a picture tomorrow that will explain it better than my words above. The hole that you drill in your kayak only has to be as large as the connector that has to pass through. I have used such fittings in the past on boats and found they work very well, though I still would not ever use them below the waterline.

One added tip that has worked well for me, whenever I disconnect the Lowrance connector from the back of the GPS/FF, I inject electrical silicone lubricant into the connector to keep it from or oxidizing and/or corroding.

Good LucK!

Joe, about the bait tank and interference:

I view the Hobie bait tank as somewhat high priced compared to what I could build of equal or higher quality. I plan on purchasing a six to eight gallon marine potable water tank and insert a quality bait pump inside with an intermittent (variable) switch that I would normally set to run for thirty seconds every five minutes. Two pvc pipes would stick out the bottom (a suction and overflow) that fit into the rear scupper holes. Access would be through an eight or ten inch hatch at the tank top. I believe I can make this for about $125 in parts and my free labor. I plan on building it this winter when I have more time available.

The bait tank pump would be powered by my Coleman battery pack previously described. I will be surprised if the bait pump causes interference with the GPS/FF. Every boat I have ever owned had a FF as well as numerous other electronic devices, along with bilge pumps, blowers, washdown pumps, and bait tank pumps powered off the same electrical system. I have never experienced interference on any of my FF although I believe it is possible if one were using a fairly limited capacity electrical supply or a low quality pump. If I am wrong and do find interference, I will have to add filtering circuitry. I'll let you know the results in a few months.

I have the pictures, Joe, but I quickly learned that you cannot simply copy and paste. It will probably take me a little while to figure out how to post. I wonder why they make it so difficult?

As promised here are my GPS/Fishfinder photos:



The above is a closeup of the watertight thru-wall fitting



Here is the wiring and bracket with the GPS Fishfinder removed so that I can get through rough water. I fill the connector with silicone dielectric lubricant to keep the contacts from corroding. Note that the bracket is completely out of the way for carrying on my roof rack.



The GPS/Fishfinder in place with ready access for changing screens and functions. The ram mount allows quite a bit of adjustment to place it right where you want. I have also attached a 1/8" red bungie tether to the unit just to be safe in not losing it.



The battery in the forward hatch. As you can see, I have added a 12volt marine outlet on the top of the waterproof case. Note the pool noodles around and under the case. All the posts about sinking made me worry about being a few miles out in the Gulf of Mexico and so I have put 22, yes 22, noodles inside the bow and stern hatches leaving the center hatch area for needed storage.

I put my 'ducer under the seat between the posts for protection. The battery is just in front of the mast tube, and the fishfinder is mounted on pvc in the mast tube. It sits in front of me so I see it without turning and it is not on a gunnel where I like to rest my feet/legs.

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Dwbuzzard

It's probably a bit late for you Joe11, but why not skip a hole? I used the same hole for the FF mount and the cable.

I custom fit a rod holder base to mount the FF, but if your using the stock ff mount, it should be even easier. Just drill out the mount base with a half inch bit and route the cable through base and mount. The Lowrance/Eagle cable is a bit under a 1/2" dia. if you trim the ears (or I suppose you could carve a little divot to get them to go through the base as well)

I glued that grommet to the cable to seal it, leaving enough slack out to go through the mount a connect comfortably. Those grommets are stamped out of a foam floor tile. Makes great grommet/gasket material.

Also note: partially inflated beach balls made great hull stuffers (floatation)

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tight lines,

Wali


"for when sleeping I dream of big fish and strong fights"