New to boats need help on wiring

wildmaninal

Lieutenant Commander
Joined
Jul 14, 2007
Messages
1,897
Hello

I recently acquired a 1977 Challenger bass boat nothing but the hull. The hull is in to good of shape to junk. The previous owner stripped all the wires out of it and now I have the honor to start from scratch. My questions are what gage wires should I use for the accessories, depth finder, trolling motor, lighters, lights, bilge pump, power trim, horn and aerator. I already got the wire diagram drawn up. Would a terminal strip be recommended. I started wiring up some of the items that I mentioned above but I don't want to have trouble later on or start a fire while I'm out in the water. I had a total of 5 boats I junked one after stripping it down, but non have a wire harness like I need.

The motor I have for this boat is a 78 model 85hp Evinrude, I bought a power trim to fit this motor but I did not get the wire harness for it. The unit has 2 plugs 2 wires per plug and one wire for the ground. Can somebody refer me to a site for a detailed wire diagram on how to hook this equipment up. I went by one diagram that I found on brokeboats.com but I couldn't figure out what one part was trying to relate to. Maybe I am looking at the wrong wire diagram for my application, I couldn't get it to work. wildmaninal@hotmail.com

Thanks for you time.

Wildmaninal
 

tashasdaddy

Honorary Moderator Emeritus
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Nov 11, 2005
Messages
51,019
Re: New to boats need help on wiring

you may be able to find the trim harness on ebay. here's a good wiring diagram. a fuses block with a ground buss bar is recommended trolling motors usually require a 50 amp fuse, and # 10 wire direct from battery. cigarette lighter, # 12, the rest can be run on 16 or 18 bring a #12 to the fuse block, then run from there, your necessary runs to equipment. it is also good to put an inline fuse near the battery, 30 or 40 amp. just in case, to keep from burning the harness.

http://forums.iboats.com/showthread.php?t=186986
 

jlinder

Lieutenant Junior Grade
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Jul 5, 2004
Messages
1,086
Re: New to boats need help on wiring

10 guage is too light for 50 amps. For safety you would not fuse #10 above 30 amps.
When considering wire guage you have 2 factors, safety (will it burn up) and voltage drop (will I lose oo much power in the wire). For safety consider that for wiring on land it goes like this: 14 ga.=15a and 12ga=20a. Then everytime you move up or down 4 guages you double or half the current capacity. 10ga is double 14ga, or 30amp. You want 50amp you need 6ga=60amp.

Voltage drop is a little tougher to calculate. Fortunately there are calculators on the web to help you. (do a search for voltage drop calculators here on iboats and you will find postings). What you are concerned with is that some power is always lost in the wire. In all connections you will find the voltage actually delivered to the device is less than the battery voltage. Even if you have a guage that is safe, if the run is long enough you will find the voltage actually delivered is too low. Consider the trolling motor - if the run is long (motor in the bow, battery in the stern), what voltage is the motor getting? Do you want to run it on 10 volts, or even 9 volts?

Next consider your connections. I like crimp connectors. When done right they are solid and last forever. Some people reccomend soldering after crimping - I don't. I think the heat can affect the crimp connector and is not needed, but that is an ongoing debate you can also search for here.

Make sure to seal your connections. The green meanies are a big problem on the water. Find some good heat shrink and use it. Try to find the type with a type of sealant on the inside. It flows under heat and forms an air tight seal around the connection.

Fuse - sure. Last thing you want is a fire. Fuses must never be larger than the current capacity of the weakest link. If you bring 8ga from the battery to the fuse block, then 14ga to your radio, you must have a fuse before the 14ga wire no larger than 15 amp.

Document, document, document. You do not need to be an artist, but make accurate drawings of everything and keep copies in multiple places. There are great drawing programs for computers that will help. If you ever have a problem you will be so happy you did.

Use different colors and pay attetion to standards for wire color codes. The last thing you want it to try to trace out a problem in a bundle of all black wires. Standards for color code can also be found mentioned here.

There is more but this will take you very far. It may sound like a lot, but if you plan it out you will be very happy with what you do.

Lot's of good people here on the forum. If you get a design/drawing post it and ask for feedback. (Make sure the drawing shows color and guage).

Good luck
 

C-VENN

Cadet
Joined
Jun 13, 2007
Messages
19
Re: New to boats need help on wiring

Just finishing up a complete re wire of a 15ft fishing boat. Take out the check book for sure. I can't believe how $$ it got so fast. That aside one trick i used on the small gauge wires to code them was zip ties on the ends. I then logged what color and combo of color went where. All the wire ends i have the zips so if there ever was a problem I can just look it up, or at least know if I see a green and white zip on a black wire I know to look for the same at the battery end.. They are cheap, lots of colors and won't wear off like tape or marker. I used as many colors of wires as i could but when i ran out I used the zips.
 

BOBBYLEE

Recruit
Joined
Aug 19, 2007
Messages
3
Re: New to boats need help on wiring

DOES ANYONE KNOW WHERE I CAN GET THE WIRING SCHEMATICS FOR MY 2000 SEASWIRL WALK AROUND 2100, FOR THE GAUGES AND RUNNING LIGHTS, REALY ALL. BECAUES I BOUGHT THE BOAT NEW AND JUST LAST WEEK I HAD TO USE THE LIGHTS, AND THEY DID'T WORK. SO I NEED TO CHECK THE CONTACTS.
THANKS,

BOBBYLEE:redface:
 

wildmaninal

Lieutenant Commander
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Jul 14, 2007
Messages
1,897
Re: New to boats need help on wiring

Thank you all very much for the input. I took electronics class back during high school years ago but I am very rusty in these skills. I mainly took the class for the computer knowledge of it. I'll let all your input sink in lol and go back to work on this boat hopefully it will all come together nicely. I looked on Ebay just browsing before I even came back to this website to check the forum and I didn't find just the wire harness for this power trim, I did find the controls with the switch, I already have the controls but there not set up for the power trim. I can't dish out $300 for the controls so I am going to half to figure out the wiring on my own lol. Thanks again
 

Big Keepers

Petty Officer 1st Class
Joined
May 13, 2007
Messages
293
Re: New to boats need help on wiring

I suggest using heat shrink butt connectors for your small wire connections. They have the adhesive mentioned above and make a water tight connection.

Your VHF, Sonar/GPS combo and marine stereo should have their own fuse links already attached to the wire harness for it. If you cut that out you'll void the warranty. I'm guessing your boat isn't long. You can use 16 gauge wire for those accessories if necessary.

I'm re-wiring my 20' MFG and I bought a 100' spool of duplex wire 16 gauge. I used that to wire my nav/anchor lights, bilge pumps, courtesy lights and horn. I'm going to label the wire runs with colored duct tape. For the fuel sender from the tank, I bought the pink wire needed. I also bought 25' of 16 gauge red and black for other incidentals I needed wire for.

I did a positive and negative bus for my accessories. From the switch to the bus I used 8 AWG wire. Same to get from battery negative to negative bus. Get a lot of cable ties, especially the ones you can screw into the side of the boat to mount the wires neatly out of the way.
 

wildmaninal

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Jul 14, 2007
Messages
1,897
Re: New to boats need help on wiring

The boat is a 15ft hull, no speedometer, or any other gages. I thought of adding a voltage gage to it though, maybe a speedometer.

Thanks again

wildmaninal
 

jtexas

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Joined
Oct 13, 2003
Messages
8,646
Re: New to boats need help on wiring

tachometer way more useful than volts or speedo, you'll eventually have a GPS anyway. lots of fishfinders have voltmeters built in.

what color are the wires on your tilt & trim?
 

burroak

Senior Chief Petty Officer
Joined
Mar 29, 2007
Messages
651
Re: New to boats need help on wiring

I can't dish out $300 for the controls so I am going to half to figure out the wiring on my own lol. Thanks again

The trim/tilt schematic on the diagram that I posted won't work?
 

wildmaninal

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Messages
1,897
Re: New to boats need help on wiring

The wires coming from the main power trim motor are 2 black wires, one has a blue ring on the end and the other green on the end, the other plug coming from the switch of some sort on the trim is a round plug with one black and one white wire on it with a green wire as ground. Sorry burroak the page may be of some help as far as the trim goes, but I'll half to save it to zoom in on the diagram to make it out. Also I have been having trounble with my internet connection so it really hadn't got to do what I need to so I can enlarge it.
 

wildmaninal

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Re: New to boats need help on wiring

I attached a diagram that I drew up see what you think.
 

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jtexas

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Re: New to boats need help on wiring

On the trim motor: apply 12V to the blue and ground the green, should trim her up. apply 12V to green and ground the blue, she should go down (why can't they all be that easy ;) ). I'd use jumper wires direct to a battery for testing.

Get yourself a DPDT momentary ON-OFF-ON toggle switch and connect it like this:
motorswitchwiring.jpg


This is a fair representation of the original dealer-installed wiring of my '79 OMC Power Tilt unit - with 10-gauge wire and no relays, fuses or circuit breakers - I highly recommend adding a circuit breaker to the 12V coming off the battery, 30 amp max, 20 would probably do it.
 

wildmaninal

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Re: New to boats need help on wiring

Thanks Jtexas for the information. I'll half to try this.
 

wildmaninal

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Jul 14, 2007
Messages
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Power trim works now

Power trim works now

I bought the dpdt switch today at a local marina and after a few minutes of running the wires the power trim works now. I still need to add the 30amp in line fuse but I am further ahead than I was.

Thanks

wildmaninal
 

wildmaninal

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Jul 14, 2007
Messages
1,897
One last dumb question lol

One last dumb question lol

I bought this blue sea fuse block with positive block and negative block/terminal. By the way it looks this will half to have the switches wired after the fuse block correct. Run the 12 gage wire to the fuse block then run to switches and accessories right? Sort of obvious forgive me I'm just playing it safe.

Thanks

Wildman
 

Big Keepers

Petty Officer 1st Class
Joined
May 13, 2007
Messages
293
Re: New to boats need help on wiring

An easy way to get power to the switches is to pig tail them together. Leave a lead at the end long enough to get to the positive terminal. Each switch will feed the one next to it. Then you just run a wire from the switch to the accessory it operates.
 

jtexas

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Re: New to boats need help on wiring

yup, 12V power to the fuse block, fuse block to switch, switch to device (+), device (-) to ground.

should really be a fuse on the 12V power line, close to the battery, appropriately sized for the gauge of wire used, in case it gets accidently grounded by, say, a stray fishhook pierces it and a ground wire - short to ground, fire hazard.

USCG standard is marine grade tinned copper strand - it's kinda pricey so I use automotive - got away with it so far. and crimped connections. soldering should not be the sole connection because the soldered joint becomes a solid wire joined to stranded; won't hold up to vibration & shock. pigtails & wire nuts are discouraged. Lots of folks recommend heat shrink to protect from corrosion - that hasn't been a problem for me (fresh-water use only) but it can't hurt.

rewiring your boat - there's lot's worse ways to spend an afternoon. if ya can find a shady spot to park. I pulled out miles of wire not connected to anything - a prior owner added or changed something he just ran new. a dozen ring terminals on the battery posts, looked like a plate of spaghetti back there, wires twisted together some with nuts, some with tape, some just bare. random in-line fuses. Very satisfying to get it all straightened out.
 
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