Fishing Boat Wiring Questions?

This site attempts to answerSmokercraft. America's first family of boating your questions about fishing boat wiring and marine electrical techniques, concepts, and products. We get lots of mail from folks in mid-project or who are just curious about their boat’s electrical setup.

There are loads of post already on the site which we hope you will browse through. If you’re trying to track down info about a more specific category, please use the search box in the upper right of this page or check out the list of various subjects farther down on this page.

If you aren’t able to find the info that you need to complete your particular fishing boat wiring project, please send us an email at boatwiring@gmail.com.

Thank you for visiting. We look forward to hearing from you and hope that you will be able to come back often.




Does 8 x 2 = 6?

Kevin,

This may be a stupid question and a stupid idea, but here goes.

I need to rewire my boat for a bigger trolling motor. Right now there are two #8 positive wires and two #8 negative wires running from battery area to where trolling motor plugs in.

Bus bar

The trolling motor manufacturer says that this model of motor requires #6 wires.

Can I attach the two #8 positive wires to a heavy duty marine buss terminal located by plug in receptacle and then a short piece of #6 to tie into receptacle? And do the same for negative side with another buss?

Thanks.

Hi

Sure.

It is not the best solution but it would certainly work fine. Make certain that you have the correct circuit protection in the positive lead at the battery.

Good luck,

Kevin




Manitou Pontoon Boat Wiring

Kevin,

I am working on a 2005 22" Manitou Osprey Pro. Is there any source for obtaining a boat wiring diagram for this pontoon?

I just recently purchased this and have been trying to fix some electrical issues. Some are relatively straightforward.

Manitou Pontoon Boat

The pontoon's stereo speaker color codes matched the vendors color codes directly, but the stereo's power hookup did not - both yellow and red leads from the stereo were tied to a the pontoon's solid red wire. There was also a red wire with a yellow tracer in the same (stereo) wiring bundle of the pontoon but it was just clipped. Is one of the these a direct battery connection and the other one an on/accessory connection? The stereo wiring diagram shows two positive connections one labeled battery and the other labeled ignition - I don't want the stereo on all the time. The sun has faded all the indications of position for the ignition switch and all the switch/breaker functions. I don't even know if the ignition switch has an accessory function/position.

I don't know if the 5 function switch panel is a standard wiring. Is there a standard layout for the switches? Since the stereo speakers and power seem to follow the standard color codes for front -rear and power, is it safe to assume all the lights, horn and other accessories follow some standard of wiring? If so what are those standards and where can I find a standard schematic or wiring diagram for those standards?

I can't wait to get out fishing on this pontoon - it has an installation for a trolling motor battery in the console with direct wiring to an outlet mounted at the bow for the trolling motor (no battery installed yet) - there doesn't seem like a way to charge this battery from the engine's alternator/charger. Is there a way to connect this battery to the the engine's alternator but not allow the trolling motor battery to try to start the main engine? I don't what to run the higher gauge wiring for that. I just want to use the trolling motor battery for the trolling motor and accessories when the main engine is not running if that is possible.

I would like to develop a wiring diagram for this pontoon but I would hate to have to start from scratch and trace out the circuits by trail and error.

Any help would be really appreciated.

Hi,

It sounds like a previous owner was doing some wiring modifications. We know the Manitou crew very well, and it is not like them to have hidden wires clipped off in their harnesses.

The key switch accessory position question is based on the brand of the engine on your boat. The easiest way to tell is to turn the key switch. It will either have 3 positions (OFF-ON-START) or 4 position (ACC-OFF-ON-START). If the key has an accessory position, it will have an A or ACC on a tab on back of the key.

There is not a standard layout for the switches on your helm. I would consider calling Manitou in Lansing MI to see if they have replacement panels for your boat that would have the proper labeling for the panels.

Here is the common boat wiring color code used by most OEM boat builders, including Manitou. You should be able to use this to trace down any wires on the boat.

If you want to charge the trolling motor battery while the engine is running, you will need to run some larger wires between the starting battery and the trolling motor battery. This wire size is based on the size of the alternator on your engine. Most VSR smart battery switch systems are capable of handling 125+ amps but the limit is the size of your alternator. If you alternator is less than 20 amp, the VSR is almost a waste of money. You will need to run your outboard at full alternator output for nearly 3 hours to replace what the trolling motor can draw in less than 1 hour.

Hope this helps,

Kevin




Sled Boat Wiring

Hello,

I have a basic 16.5 aluminum open river sled with a single engine. Currently the motor runs off one 12v battery with a manual bilge pump switch hooked up.

Koffler River Boat

I would like to add a second battery for:

  • Electric trolling motor
  • Navigation lights, to be installed
  • Bilge pump to this battery
  • Fish finder
In addition I would like to add a 12 volt two bank marine electrical boat battery charger for both batteries. I will add a 6 position fuse panel to the mix.

My questions or concerns:

Any interaction between the 12vdc system and the 120v battery charger to insure that I don’t get a ground fault. Would adding a battery switch assist with this potential problem or will a bus bar be necessary?

Thank you for any input,

Hi,

Since your system is 12 volt only, I would connect all of your grounds together, including your batteries, at a common bus.

You will only trip a ground fault outlet if there is a fault from ac hot to boat ground and the boat is connected to earth ground.

If this happens it will not matter if you have a battery switch or not.

Hope this helps.

Kevin




Crestliner Wiring Upgrade

Kevin,

Could you please check out my homemade boat wiring diagram? It’s for my 17.5′ Crestliner Fish Hawk.

As you can see, I added and wired the two Attwood battery selector switches and a fourth battery to the system (Battery 2) and wired all the batteries in parallel. I also added the Blue Seas fuse block, all lighting, fishfinder, trolling motor, etc.

Crestliner boat wiring diagram

Click to Enlarge

My goal here is to be able to run the trolling motor off the extra battery if needed and/or to be able to start the motor with the extra battery if the main died. Also, to run all the lights off the extra battery for night fishing. I’ve yet to turn both switches to “both” because I’m not sure if that would be bad for……..everything.

I’m obviously an amateur at this so was wondering if you think it’s a safe setup assuming all the fuses, connections, wire gauge, etc. are kosher? I haven’t had any trouble yet but I’m a little nervous about burning something up.

I’d really appreciate your input if you can decipher the wiring diagram.

Thanks,

S.D.

Hi,

I would make a couple of minor changes:

  • Move the trolling motor circuit protection to the trolling motor side of the switch.
  • Add circuit protection for the Blue Seas fuse panel at its connection location to the boat battery switch.
  • Use the same size boat battery cables for all of your battery link wires. You call out 4/0 for the positive lead (I would assume you mean 4 AWG) but not on any of the other cables.
  • If the trolling motor batteries are near the bow of the boat I would consider adding circuit protection at each end of this wire to help reduce the risk of a catastrophic fault.

Hope this helps,

Kevin

Kevin,

Thanks for the help Kevin. I’ll do all of that.

Also, I was wrong about the battery cable being 4/0, its actually 1/0 welding cable.
Thanks again,

S.D.

Hi,

Most people don’t use welding cable on boats or cars because it is not oil resistant.

Kevin




Kayak Power

Hey Kevin,Motorguide trolling motor

Your site is amazing. Thanks for all the info.

Now here is my boat wiring question:

We have a Native 14.5 ft Kayak. It only weighs 75 pounds and wish to power it with a 12 volt Motorguide trolling motor on some of the quieter lakes for fishing.

What are the battery options? Will a 24 volt with 93 amp hours work? And for how long? From reading your posts I learned we need a better charger than the 25 year old trickle charger we have, any gems you recommend?

Thanks again.

Hi,

Most of the time, you don’t want to discharge a boat battery below 50%, so you are only going to use 46 of the 93 amp hours available in the battery. The small, 30 lb thrust trolling motors draw about 30 amps at full power. At wide open, you can expect the battery to last about 1.5 hours. A 5 amp charger would take about 9 hours to recharge the battery after use.

Hope this helps,

Kevin




Engine Harness Search

boat wiring

Kevin,

Could you please tell me the best place to find an oddball boat wiring harness? I need one that will fit a Johnson 75elr78c engine from the red plug in the ignition switch?

Thank you for your help.

Hi Bill,

I’m sorry, but neither of our wiring sites have anything like this. If it were me, I would try ebasicpower.com.

Good luck,

Kevin




Stereo Works. Boat Doesn’t.

Kevin,

I recently bought a 16 foot Smokercraft fishing boat with a 60 hp Mercury EFI 4 stroke engine. I also bought a stereo unit for the boat and was hooking it up and now I have 3 problems.

  • No power tilt and trim
  • No turn over of the engine with the key start
  • No power to my fish/depth finder.
  • JBL Marine Speaker

I have checked the fuses. Both the one of the engine as well as the one on the fish finder.

I ordered a key switch unit and a 20 amp circuit breaker. If this does not fix the problem—do you have any suggestions of where I should look next?

All of the above worked before the stereo hook-up in which I connected the power cable to the ignition.

Thanks for your help!

Leroy

Hi Leroy,

There must be a blown fuse somewhere on your boat. Is there an in-line fuse at the key or an ignition fuse on the fuse panel?

I would use a meter or test light to look for 12 volt power at the key switch and make your way back to the engine.

I don’t believe a new key switch is going to solve the problem.

Let me know,

Kevin




Light Switched

Kevin,

My boat’s navigation light switch is spliced into the negative wire.

Is this acceptable or should the switch be rewired into the positive wire. The positive wire is fused with a 2 amp fuse. Bow light

Your help will be greatly appreciated.

Thanks

Hi,

Although it is not a common practice, there is nothing really wrong with switching the negative lead instead of the positive lead.

The best practice is: source of power, circuit protection within 7 inches of power supply, switch, device, ground.

Hope this helps,

Kevin




Static Stopper

Hi Kevin,Zinc anode

When storing a small vessel on a trailer for the winter, is it advisable to connect a ground clamp to ship’s ground, ie, the zinc on the outboard?

Regards,

Robert

HI Robert,

There is no reason to unless you are doing something on-board that may produce a large static buildup such as running a vacuum cleaner.

Enjoy your winter,

Kevin