Need wiring tips for installing a gps chart plotter

[dailytrek]

Although I've wired several entire homes and many boat trailers myself, I have no experience wiring boats and am seeking your wisdom. I bought a nice swing arm mount and installed so I can read the screen from the cockpit or cabin. My questions:
1. Is it necessary to wire to the main switch block or OK to go directly to the battery using an intermediate fuse and possibly a switch? All the switches are in use. There is already a switch/fuse for the existing instruments (depth and speed) and I want to keep the existing instruments available to use.
2. Is there a particular type of marine wire connector I should use? (To many varieties/unneeded quantities at WestMarine) Can I get them only at marine stores or is automotive OK?
3. How do I best attach the transducer to the interior of my hull?
4. I need to run two groups of wires from the unit through my fiberglass interior next to where I mounted the unit and need rubber protection grommets....where do I buy?
Thanks for your help!
--Christian

[TeddyDiver]

A quick question, do you have a main fuse, main switch and or busbar between the battery and the switch block?

[Lennie]

1. You can.
2. Use adhesive heat shrink connectors and a good crimp tool. And use tinned wire sized for 3% or less voltage drop.
3. Some just use silicon to hold it to the hull. I put one in an old water bottle and filled it with the pink antifreeze. For some reason water didn't work as well and in the NW in might freeze.
Your best bet is to install a unit that is designed to shoot through the hull. I only used the bottle until the next haul out. Never happened sold the boat.
4. You can find rubber grommets in any hardware store. I like to use a 2 pair cable if you have room. more protection and not much more cost. Genuinedealz(Marine Wiring, Boat Cable and Electrical Genuinedealz.com) is a good source for cable and heat shrink connectors.

That's my advice for what it's worth.
Good Luck,
Len

[GordMay]

Greetings and welcome aboard the CF, Christian.

[OS2Dude]

Regardless of your experience wiring structures and vehicles, I would get a book on marine wiring and read it. A marine environment is a completely different animal than a house or a car. You NEED to use stranded tinned marine cable on a boat. You may be able to get away with using something else for a while, but eventually someone will pay for it.

Anything that is related to SAFETY you need to spend the extra dollars for a marine rated solution. This includes hose clamps for thru-hulls, wiring (Even 12 volt. as the devices powered by it may be needed in an emergency, but especially any 110 or high amperage situation like engine power), liquid handling (fuel, water, waste), etc.

Stereo speakers you can use regular wire for, if it fails it is not catastrophic. However it is a different story if a high amperage cable corrodes and resistance goes up and starts a fire...

[dailytrek]

I don't believe I have a main fuse but just a battery selection/shut off switch.

[TeddyDiver]

Originally Posted by dailytrek

I don't believe I have a main fuse but just a battery selection/shut off switch.

You should have a main fuse closest to the battery.
What comes to connecting the GPS unit, it can be connected in the switch block with another device IF the fuse and the wiring is appropriate for the multiple devices in the same circuit. But you must do the math and check the amps and wire gauge..

[rikker]

Christian,
I just wired the new Garmin GPS chartplotter on my new to me sailboat this past spring and it came with all the necessary cabling and fuses. You could wire it direct to 12v with it's included fuse, but I found it handy to wire it (piggyback) to the Nav/Instrument switch on the main panel. Then it turns on and off with all the instruments with one click.

Rick

[Celestialsailor]

This book will put you out of your misery.

Robot Check

[TeddyDiver]

^ second that
Ps page 184

[Nicholson58]

However else you choose to handle things, our experience regarding possible lightening strikes suggests that using a double-pole toggle switch to interrupt both negative and positive connections may offer a degree of protection. We have added these at every instrument close to the device. Get these switches from any marine chandlery. All modern electronic devices have software power switches on only the + side. A strike can easily blow right through the power-on circuit and the other side is hard wired to ground.


Typical Marine wiring will be:
Batteries to a main panel
Main Panel - main disconnect breaker
Main power key-lock power on. (possible A or B battery switches)
Distribution on the main panel to breakers for specific circuits.
Breakers normally are sized to protect the wires although the breaker may be smaller.
Circuit labeled INSTRUMENTS may power a remote terminal strip for distribution to users.
Each user probably has a vendor furnished in-line fuse of the proper size to protect the device. In the nav station I like to replace these with panel mount fuses.
Boat negative ground will land on terminals - eventually gathered to the main ground.
Main ground to a shunt.
Shunt to battery negative.


You should only use marine rated tinned wire. Not so important on the Great Lakes but salt air will degrade bare copper multi-strand wire. This makes it difficult to make a good connection later and can cause hot spots in a crimp connector. If you are inspected or need to make a claim for fire, proper wire could be a big deal.

[travellerw]

Follow the advice and use actual marine crimps with adhesive lined heatshrink. Please don't use a crappy stripper, cutter, crimper. They do not produce an adequate crimp. You need a ratcheting crimper at least.

%95 of problems with wiring on boats is the terminations. Take you time doing the shrinks and make sure they are sealed well.

[Celestialsailor]

I have always taken it a step further no mater what the crimp end is...and that is to crimp, solder and shrink fit the ends.

[dailytrek]

Really great suggestions! Thank you.
--Christian

[Nicholson58]

Originally Posted by Celestialsailor

I have always taken it a step further no mater what the crimp end is...and that is to crimp, solder and shrink fit the ends.

I do this too & use non-heat shrink connectors. I pack the heat shrink with 5200 so that it squirts out when I shrink it. If there is concern for strain relief I add additional layers of heat shrink. Pre-tinned wire is really easy to solder.