Need wiring tips for installing a gps chart plotter

[ramblinrod]

Originally Posted by Nicholson58

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.

Good show.

I use silicone sealant for sealing connections in heat shrink. It is more temperature / solvent stable than other sealants.

Ramblin Rod
Raymarine Certified Installer
About Sheen Marine

[ramblinrod]

Originally Posted by 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

This post begs for my standard response...

This kinda feels like the time I had kids pull up alongside in a run-about and ask for directions to a destination out in Georgian Bay.

After considering that I could be sending them to their peril if they didn't get my instructions right, I told them how to get to the nearest marina to buy charts.

So, the best advice I can give is to read ABYC E11 (Electrical Standards) cover to cover, and if there is anything you're not sure about, ask. If you have to ask more than 3 things, you need to read it again.

While Calder's and Casey's books are pretty good about certain systems, they really don't cover good general wiring practices well enough. (It's also a, "Just because you saw it on the internet (or read it in a book), doesn't mean you can do it", kind of a thing.

Next, my best advise is don't go cheap on the products. Use Ancor wiring and connectors, Marinco shore power cables and connectors, and Blue Sea panels and breakers.

Equipped with this, please don't burn your boat to the waterline (which is all too easy, even if you think you have it all figured out.)
There are things one just can't learn from an evening of reading or an hour of YouTube video viewing.

Just because 12Vdc won't electrocute you, doesn't mean it doesn't deserve your full respect and attention.

Before I knew what I know now, I was guilty of all kinds of electrical safety issues, and I was an Electronic Engineering Technician with 30 years experience.

As part of my current marine electrical seminar for boating groups, I start out asking...

"Who does their own electrical repairs and improvements?"

(About 50% of hands go up.)

Then I ask, "Of those, who believes it was done properly?"

(All the hands stay up.)

Then I ask, "Who is so sure of that, they will invite me aboard to perform an electrical inspection, free if it's safe, $200 if I find one electrical safety issue?"

(All the hands go down.)

After the seminar, when I've shown several images of tragic boat fires, and gone through many of the electrical safety issues I encounter, 2 or 3 come up and ask me to do a $200 inspection. They know (now) that they have (and I am going to find) electrical safety issues.

The reason I can do this, and stay in business, is because in my experience to date, about 90% of all boats on the water today have unsafe electrical issues, and about 50% of owner DIY work, is absolutely atrocious. If asked, nobody will say, "The wiring I performed is all wrong". They simply don't know just how unsafe it is.

I'm not saying, "Don't do your own electrical work." I'm just saying, "If you are going to do it, for everyone's sake (yourself, your crew, the next owner, and the boat), ensure you do it right, 100% right."

When you need it, a bilge pump must work, to the best of its potential performance, or a maritime tragedy could occur. When you need it, a VHF must work, to the best of its potential performance, or a maritime tragedy could occur. When you need it, the engine starter must turn, to the best of its potential performance, or a maritime tragedy could occur. You get my drift.

There are few electrical / electronic devices aboard that could not become a critical piece of safety equipment some day. Even a Marguerite blender with a botched plug replacement. (A line/neutral short, with a secondary boat wiring or current limiting fault, could result in a catastrophic fire.)

Some time ago on a large forum, I read a thread of a bunch of people (about a dozen) telling the OP that it is OK to use 16 gauge wire when adding LED fixtures to existing cabin lighting wiring. Not one of them said (or probably even knew) that in doing so, one must address current limiting in the new branch circuit, or an electrical fire could ensue before the original fuse or breaker ever trips.

Sailing gives one all kinds of freedom, to move without the sound of infernal combustion engines, to move without roads or guard rails dictating where, to move without adherence to strict schedule, and so on.

It also gives one the freedom to mess up electrical stuff if they don't know what they are doing, and the results could be tragic.

Ramblin Rod
Marine Service Provider
About Sheen Marine

[dakno]

As far as the transducer goes, I have installed thru hull's in 2 boats in the interior without drilling. Find a spot on your outer hull, forward of the keel , as close to center line as you can, where you have a unobstructed shot to the underside of hull. Take a solo cup, cut the bottom off, place on the cleaned, prepared spot, fill i/2 with silicone, insert the transducer as far in as it will go. Thats it. There can be NO air between the bottom of transducer and hull. You have to be sure not to have the ducer where it will get knocked around.

[rwidman]

Originally Posted by 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

I think you need more help than you can get by posting a few questions on the Internet. Besides, you've already gotten some bad advice, you just don't know the good from the bad.

Buy the book recommended above and study it cover to cover. If you don't understand it, buy another and study it.

I will say this: Buy all your materials from a marine vendor and don't solder anything, especially wires you've already crimped.

[ramblinrod]

Originally Posted by dakno

As far as the transducer goes, I have installed thru hull's in 2 boats in the interior without drilling. Find a spot on your outer hull, forward of the keel , as close to center line as you can, where you have a unobstructed shot to the underside of hull. Take a solo cup, cut the bottom off, place on the cleaned, prepared spot, fill i/2 with silicone, insert the transducer as far in as it will go. Thats it. There can be NO air between the bottom of transducer and hull. You have to be sure not to have the ducer where it will get knocked around.

Airmar produces depth sounder transducers specifically for in-hull (vs thru-hull) mounting. For those, just follow the instructions supplied.

To mount a standard thru-hull transducer in hull, here is the process I follow.

1. Connect up the depthsounder and hang the transducer in the water pointing to the sea bottom to verify it works.

2. If the unit provides a signal strength value or graphic display (some it is by the thickness or colour of line representing the sea bottom), record it. (If a graphic display, take a photo with your phone or camera.) This is your base reference.

3. Now find a location for mounting the transducer inside the hull that best meets the following criteria:

a) Forward of the keel.
b) With minimum deadrise (ie. surface is horizontal and parallel to sea bottom.)
c) Where there is no core in the hull. (If the hull is cored, with balsa for example, see if the manufacturer had the foresight to leave an uncored area for mounting thruhulls.)

4. Fill a zip lock sandwich bag half full of water. Squeeze out all the air and seal it.

5. Sprinkle some water in the desired mounting location.

6. Lay the water filled baggy on the wet spot.

7. Press the transducer face into the baggy.

8. Turn the unit on, and check the signal strength.

9. a) If the signal strength is near equal to the earlier test, the location is good, then step 10.

9. b) If the unit doesn't work, or the signal strength is much weaker, look for a different location, then step 3.

10. Dry up the water on the hull surface, and sand it with 80 grit or coarser, vacuum and wipe with acetone.

11. Sand (by hand) the transducer face with 80 grit or coarser, vacuum, and wipe with acetone.

12. Pour a small amount (2 teaspoons) of mixed epoxy (no filler) on the spot. (Remember it is supposed to be flat; if not; make a little dam of some caulking material, to prevent epoxy from running down hill.)

13. Set the transducer face into the epoxy, first on an angle and then levelling to avoid trapping air bubbles under it.

14. Tape the transducer in place, until the epoxy cures.

15. Before the epoxy cures, turn on the unit and check the signal strength again.

16. a) If signal strength is weaker, then reset transducer face in epoxy avoiding air entrapment this time.

16. b) If signal strength is OK, then step 17.

17. End

As an alternative to direct epoxy bonding, one can adhere a tube to the hull surface, and suspend the transducer in the tube filled with RV anti-freeze. (This is the preferred method if there is no suitable mounting location with a deadrise of less than 30 degrees.)

I have heard of people using all kinds of materials for hull bonding, including silicone sealant, silly putty, and even peanut butter. Any of these materials will work (sorta) but epoxy will work better (greater signal strength).

The goal is to achieve max signal strength, as there will already be some signal attenuation by shooting through the hull.

Since a depthsounder is a navigation device (and your safety could depend on it), the goal should be to achieve the highest signal strength (least attenuation) possible. Some day your GPS may crap out, and you (or the next owner) may need your depthsounder to follow a chart contour near its max range. If range has been needlessly cut in half by using some attenuating bonding material, that would be undesirable at that moment.

I have reliably read depths up to 600 feet (the software limited range of the depthsounder) using this method.

Ramblin Rod
Certified Raymarine Installer
About Sheen Marine

[dailytrek]

Thank you Rod for your detailed responses. Very helpful.

[ramblinrod]

Originally Posted by rwidman

I think you need more help than you can get by posting a few questions on the Internet. Besides, you've already gotten some bad advice, you just don't know the good from the bad.

Buy the book recommended above and study it cover to cover. If you don't understand it, buy another and study it.

I will say this: Buy all your materials from a marine vendor and don't solder anything, especially wires you've already crimped.

Ya have to be careful with the advice not to solder.

I would suggest the average DIYer should not solder.

Someone skilled in soldering, that can be another story.

I have many, many, years of soldering experience, most in a manufacturing environment. We used to have testers for measuring crimp integrity (destructive) for wiring in nuclear power station panels. One day, I mentioned to the Quality Control Manager that I could make a solder connection in stranded wire, far more reliable than a crimp connection. Of course, he thought I was full of crap, and challenged me to prove it. So he brought in wireman to put butt crimps in a number of wires.

I then made a number of soldered splices using the same wire.

The crimps failed consistently at 75 lbs +/-5 lbs pull (45 lbs required to meet spec). In every case the crimped connector pulled off. My solder splices failed between 155 and 175 lbs pull. In every case, the wire broke at least 1/2" away from the splice.

Some people claim the hardening by making the stranded wire solid when solder is applied is a problem. Not so. When a crimp is applied properly, the strands are cold formed into the equivalent of a solid. In every case, whether crimp or solder, the splice or joint has to be mechanically secured to prevent flexing or vibration from affecting the joint integrity.

Done properly, a solder joint can be far better than a crimp. Few can solder properly, consistently.

The problem is, done improperly, a solder joint can be far worse than a crimp.

A crimped connection is more likely to meet a certain standard of quality, regardless of who does it, or how skilled they are.

A solder connection quality is much more dependant on the skill of the technician.

Therefore most quality control systems and electrical standards, tend to prefer crimps.

Some believe all electrical standards prohibit solder, which is rarely true. (There are millions of standards with who knows how many variations.) When the standard indicates something to the effect of, "wire connections shall be mechanical and not be made by solder alone", this does not mean a crimp connector is essential (as some assume). What it means (usually) is that solder cannot be the only thing holding the wires together. A proper wire splice that is soldered, does meet the requirements of these standards, as the splice is the mechanical connection, and the solder is sealing the splice and adding strength.

For customer boats, I rarely ever solder (except for wire smaller than 18 AWG) as it takes too long. For my own boat, if I have time to spare, I solder rather than crimp.