# About to start from scratch wiring my boat



## wmk0002 (Jul 28, 2016)

I'm about to get serious about wiring my new boat up. Below is a picture of my hull, a 2016 Alumacraft 1648 NCS (also see my sig for more pics). It is farther along than that old picture shows but it is essentially the same just now with a temporary floor, 46 lbs thrust 12VTM mounted on the left of the bow, and a front seat pedestal.







I plan on placing my battery in the stern. From there I want to run wire over the transom and under the corner transom brace and fish the wire to the TM through left gunnel tube where it will come out and I can mount the receptacle to the TM bracket. I also have a new Helix 5 SI/GPS and RAM mount which I would like to also mount on the left side of the boat at the forward edge of rear deck. I plan on mounting a switch panel on a weatherproof electrical junction box (or equivalent type box) on the right side of the boat just forward of the rear deck, possibly mounted on a piece of aluminum spanning between the first two ribs. The switch box will control navigation lights, bilge pump, and accessory lights for now. 

I am familiar with the proper way to size wire, connect it, and protect it. But I am unsure of things like interference on the fish finder or fishing wire through the gunnels. I was wondering if anyone had any advice on the neatest and best way to locate the wires on this hull? Right now I am leaning on running the TM wires like I mentioned and running the Helix power and transducer cables through a bottom strake under the rear deck and then over and up to the location I want to best avoid interference. For the switch box, I'd like to run a primary power and ground wire through the right gunnel from the battery to the box and then run any light or accessory wires to the bow through that gunnel as well. 

Should the routing I am thinking about reduce interference to the fish finder or will there still likely be some since everything is planned to run off of a single battery? For now, I plan to use the Helix in the stern even when fishing from the bow until I can afford a cheaper DI model to mount up front, so the TM and Helix will be used simultaneously. And if it ends up I likely will need a separate battery so my TM can have one dedicated to it, can I then run the Helix's wires in the gunnel with too or will that also very likely cause interference?


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## jethro (Jul 29, 2016)

I run both my trolling motor and Helix 5 off the same deep cycle battery and the wires run right next to each other for about 5 feet. My 25 hp electric start motor is also on that battery. I never noticed any kind of interference and I know my fish finder well. I personally would run all the wires under the floor so you don't have to run a heavy gauge trolling motor wire over the transom. Much cleaner under the floor and I would think you'd have to drill a hole in the rub rail for the wire which I would personally want to avoid.

I used to be big into high end car audio when I younger, so I know all about interference when you run wires close to each other. But I don't think the fish finder works the same way. Nothing seems to interfere with my sonar signal, gas motor running or not, trolling motor running or not or anything else in my electrical system. I think that the amps drawn from the battery for a fish finder are so low that there is very little to no signal interference, but that is just my experience.


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## wmk0002 (Jul 29, 2016)

Thanks jethro. I'm still open to running the wiring under the floor. I really didn't want to do it on order to keep the strakes free for good water drainage but it probably won't really hinder that much.

When you ran yours under the floor and reached the front deck how did handle the wiring from that point forward to the TM? We may have totally different layout boats but since I am leaving my foam under my front deck intact, I think I would have to use some type of wire loom and run it up and then down the side to install the TM plug receptacle.

Regarding fishing wire through the rail/gunnels, I did buy a nice 160 piece rubber grommet set off of Amazon a few weeks back that should really clean up the holes in it if I decide to go that route.


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## wmk0002 (Jul 29, 2016)

I also think most of the fish finder interference issues come from TM mounted transducers rather than the setup I will have. I was just unsure if there was a possibility to get some interference with it as well.


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## perchjerker (Jul 29, 2016)

I would not worry about running the fish finder off the trolling motor battery.

I do and have zero interference when the motor is running

the battery acts like a giant capacitor and will absorb any interference, unless you have the lead wires running along each other

keep them separated and it will be fine from that respect.


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## jethro (Jul 29, 2016)

wmk0002 said:


> When you ran yours under the floor and reached the front deck how did handle the wiring from that point forward to the TM? We may have totally different layout boats but since I am leaving my foam under my front deck intact, I think I would have to use some type of wire loom and run it up and then down the side to install the TM plug receptacle.[\quote]
> 
> My trolling motor wire is under the floor until it gets to the side console and then it's exposed and run on the side wall just under the gunwale fastened with clips. That's the way my boat came to me but when I redo the floor I will run everything under the floor up to the bow. My floor goes all the way to the bow. Then the wire will be exposed from there.


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## wmk0002 (Jul 29, 2016)

Ok, I will definitely separate th TM and FF wires to be safe. I'm going to use 4 AWG tinned marine wire for the TM, which has an OD of 0.386", so if I decide to fish it through the gunnel there won't really be any room for any other wires anyways.


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## richg99 (Jul 29, 2016)

Not sure if this will help, but....if you do have to run some exposed wire ( i.e as one poster said, from the console forward)...in the past I have run that wire through some PVC conduit, or even CPVC if the wire fits. 

Using wire ties that have the screw hole as part of their construction, you can bring that PVC up tight to the gunnel. Drawn up tight and straight, and painted the color of your boat, you might not even notice it.

richg99

https://www.cabletiesandmore.com/mounted-head-cable-ties.php


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## BigTerp (Jul 29, 2016)

All my my wiring and motor controls run along the gunwale. The wires are concealed in wire loom and look nice and neat. Not sure what your planning floor wise, if any. But having access to your wires without having to take up the floor is a plus.


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## wmk0002 (Jul 29, 2016)

BigTerp said:


> All my my wiring and motor controls run along the gunwale. The wires are concealed in wire loom and look nice and neat. Not sure what your planning floor wise, if any. But having access to your wires without having to take up the floor is a plus.




That is a good point to consider. Right now my floor is 1 & 1/2" foam board topped with a rubber stall mat....so easy to remove as of now. However, I plan to replace the mat with an aluminum sheet/hydroturf in the near future. Being riveted my hull flexes and twists pretty good in chop so when I do a more permanent floor I do plan to use as few fasteners as possible to allow it to retain a little flexibility. I'll keep that in mind moving forward in how it will affect my wiring.


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