How to get power to compass? Wires seem VERY small.

[SteelCruiser]

Have a compass, picture attached.
Have a steel hulled yacht.
There is currently, no power to the cockpit.
There seems no simple / WATERTIGHT method to get power to the cockpit.

At moment, I sit the compass in a plastic box jammed under a seat in front of Companionway.
Mostly, Only use compass when no land / lighthouses in sight.
At night time, I turn on & shine a 'red' light to see heading, then use wind/stars until shining 'red' light again.
.
I'm wondering how simple it would be to add power via a battery & switch ?
...that could sit out in the same box... And obviate the need to get power from down below and connect to the main panel?
.? Can I use one of those big torch batteries?



Sent from my iPad using Cruisers Sailing Forum

[atoll]

on past deliveries where the compass light was broken I have just used a red LED head torch attached to the binnacle

[Sun and Moon]

Originally Posted by SteelCruiser

Have a compass, picture attached.
Have a steel hulled yacht.
There is currently, no power to the cockpit.
There seems no simple / WATERTIGHT method to get power to the cockpit.

At moment, I sit the compass in a plastic box jammed under a seat in front of Companionway.
Mostly, Only use compass when no land / lighthouses in sight.
At night time, I turn on & shine a 'red' light to see heading, then use wind/stars until shining 'red' light again.
.
I'm wondering how simple it would be to add power via a battery & switch ?
...that could sit out in the same box... And obviate the need to get power from down below and connect to the main panel?
.? Can I use one of those big torch batteries?
Attachment 119441Attachment 119442


Sent from my iPad using Cruisers Sailing Forum

That looks like a 6v battery, and your compass presumably is 12v. You could use two of them. You'll have to figure out amps of compass light, and amp hours capacity of batteries to know how long it will run for. You might also consider a small recharchable 12v battery and a solar cell.

[Reefmagnet]

It's pretty easy to rig up a red light emitting diode to replace the compass light if you can solder (or crimp!). You'll also need a 1/4 watt resistor in series to limit current. Hi intensity LED'S work best. Limit current to about 30 mA (I might need to be corrected on this) in which case you'd need a 150 ohm resistor for 6 volts and a 390 ohm resistor (1/2 watt rated) for 12 volts.

Much better than a filament bulb that'll run down the battery pronto. You can tape your creation to the compass or just replace the bulb with your led altogether.

One other thing to consider is that the compass uses so little power for its light that you can run the tiniest pair of wires to it. Done well, the wires should last for years.

And yet another thing, consider a cheap 12 volt gel cell instead. Next to no mod required and rechargeable during the day!

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[transmitterdan]

You can use a pair of D cell batteries in a plastic holder. If the compass has a built in LED it probably has a resistor sized for 12V and it is probably covered with shrink wrap somewhere inside the housing close to the LED. Open the housing and carefully cut away the shrink wrap and measure the value of the resistor with an ohmmeter, call that value R1. Compute the required resistance for a new resistor like this: divide R1 by 2.5 and select the resistance nearest that number. Solder this new resistor in parallel with the existing one. This will produce the same brightness as a 12V battery when powered by the 3V pair of D cells. Seal the new resistor with self amalgamating rigging tape and a couple of tie wraps.

If you want to use the 6V lantern battery then select a resistor the same value as R1 and solder it in parallel with the existing one.

When you want to install the compass permanently just remove the extra resistor and re-seal.

[hamburking]

Be aware that batteries (and electric fields) will have a big effect on your compass, if in close proximity. This happens all too often when people hold a flashlight up to the compass to see it at night.

Also, since you have a steel vessel, compass error known as deviation can also be a concern. All that steel affects your compass. It would be best to have a fixed mount, and measure the deviation at different headings and different angles of heel. If your engine, batteries, or charging system are close to the compass, they can also affect it.

A good quality compass is always a good thing to have aboard (especially to predict collisions). However, for heading info, independant of your other electronics, you could use an electronic compass (with built in light) or just use a simple handheld gps, like a garmin etrex. I used an old model etrex (yellow) to cross the atlantic ocean, and it worked just great.

And finally, my plastimo handheld compass has that glow in the dark paint...you shine a light on it once, and it stays self illuminated for quite a long time, with no electricity at all.

[Chuck Hawley]

Here are some additional thoughts:

1. The fact that your compass has tiny wires already implies that either the lamp or LED draws a tiny amount of current. Compasses have dim red lighting so they don't hurt your night vision. The wires are confirming a very tiny load.

2. It was probably intended to run on 12V, so feed it 12V. This can be a small battery pack for some other purpose, or a brick of 8x AA batteries, or something. The batteries will frequently be magnetic, so you need to put them remotely from the compass.

3. On a steel boat, a small compass like this will be difficult to swing. Way to complicated to go into here, but that's why steel boats have large steel spheres to reduce the flux focussing from having a long steel object. If you haven't at least compared your compass to a GPS that's reading out in magnetic heading, you should.

Chuck

[Sailshabby]

You could run the wires to a 12v cigarette lighter (attach the wires to the male plug). This'd let you unplug it when not in use. You'd be able to use the outlet for a spotlight, etc., when not in use.

[hamburking]

Originally Posted by Sailshabby

You could run the wires to a 12v cigarette lighter (attach the wires to the male plug). This'd let you unplug it when not in use. You'd be able to use the outlet for a spotlight, etc., when not in use.

+1 ... thats exactly what I have done (on several boats) in the past. I use the outlet to power the autohelm during the day, anchor light at night, and lots of other things like spotlight, phone charger, and portable dvd player.

At one point, I plugged a small solar panel into the outlet, to keep the battery topped up...I had no good place to mount the panel, so just laid it out in the cockpit when leaving the boat. Thieves visited my boat one night, and the problem of mounting the panel went away.

[Scaramanga F25]

Most of us assume that you have a compass specifically designed for a steel hull vessel

[Nicholson58]

When I re-wired our compass light, the original was incandescent white. I replaced with red LED. No commercial replacements are made for this. As much as I dislike automotive-like LED's, I caved and used two 12 VDC Radio Shack tiny panel pilot lights. We are 24 VDC so I wired in series. These have integral dropping resistors. Soldered together as close coupled as possible, I was able to make them fit in the available space. For this purpose, you want the smallest power, lowest lumen output you can find. This will consume only a few mili-amps. This has proven to be more than bright enough. I think that you could also use Blue Sea panel pilot light replacements as well. You will not need a huge battery to run this a long time.


There are products made for sealing wire penetrations.

[tinkrman69]

What your asking for is not a simple way to light a compass. No more simple than running power to the cockpit. Not to mention the wast of time setting up some thing temporary. Also just stuffing a compass on a boat leaves a lot of error, north could be as much as 20 degrees east or west and east could be another 15 degrees north or south. If it's not mounted and swung...calibrated for the boat in what ever location it's mounted... it won't be very useful.

if you mount it in a location that you'll eventually mount the permanent one and run power to it, you will have most of the work done for the permanent one when you get it. As far as "watertight" wiring to the cockpit there are many "simple" ways to accomplish this.

there are many books that you can read to learn how to do the work that boat ownership entails. You can learn to do the labor on the boat or make lots of money to hire someone else to do it for you. one book in the electrical area is Don Casey's book " sailboat electircs simplified" there are other books about mounting and calibrating compass' and others on maintaining steel boats, even on welding...something a low budget person should learn on a steel boat.

I may sound a little negative on this and maybe this is why. there is a steep schooner in a south florida harbor with only one sail, a red and green flash light for bow lights and a portable anchor light for the stern. He jury rigged the shift cable with string...yes string...when he was coming into the "crowded" anchorage his string broke and he couldn't reverse it to slow down. when he ran down to shift it by hand the helm turned to starboard. by the time he came back topsides, he was a foot from my boat. luckily the damage was minor...as he had no money to pay for repairs on my boat. His rudder broke a month later as he saw no need to change the Zincs more than once every 4 or 5 years, not to mention clean the bottom. his anchor chain broke last year. he had said 3/4 inch chain is more than enough to hold this 40 foot yacht, it's just a little rust. It was really 1/2 inch chain with flaking rust, it just looked bigger. he's since moved...up?...to another boat, a trawler with a solid hunk of rust for main propulsion. He still owns the other one. Its debatable on which one will sit on the bottom first.

it takes a lot of work and know how to live on the sea or a lot of money. Hope your willing to learn how. this life can be grand if you are.

[Sempersafloat]

Hi, just another bit of info, you should also twist the wires going to the light, as current flowing through straight untwisted wiring produces a magnetic field. The field is still there with twisted wiring but basically the twists create opposing fields which tend to cancel out. We have a steel boat and the steering compass ideally needs to be a metre from any steel, and even then you might need compensators to correct the deviation, the ideal is a fluxgate sensor about 6 feet up the mast. Much higher and you have to start thinking heeling errors. Why is life never simple?

[ramblinrod]

Originally Posted by SteelCruiser

Have a compass, picture attached.
Have a steel hulled yacht.
There is currently, no power to the cockpit.
There seems no simple / WATERTIGHT method to get power to the cockpit.

At moment, I sit the compass in a plastic box jammed under a seat in front of Companionway.
Mostly, Only use compass when no land / lighthouses in sight.
At night time, I turn on & shine a 'red' light to see heading, then use wind/stars until shining 'red' light again.
.
I'm wondering how simple it would be to add power via a battery & switch ?
...that could sit out in the same box... And obviate the need to get power from down below and connect to the main panel?
.? Can I use one of those big torch batteries?
Attachment 119441Attachment 119442


Sent from my iPad using Cruisers Sailing Forum

Based on your query, I recommend getting someone knowledgeable and experienced at installing marine navigation instruments to assist you.

What kind of boat and where do you sail?

A compass is pretty important piece of navigation equipment and your plan sounds haphazard at best.

There is no point in mounting a light on a compass that gives false readings due to improper selection, application, and mounting.

When you have all that sorted out, I recommend using proper marine grade wire and connections, via switch (perhaps nav lights; you have these for night sailing when you need a compass light, correct?) and fuse or breaker from the house bank.

As far as waterproof surface penetrations go, I typically use BlueSea Cable Clams.

Ramblinrod
Marine Service Provider
About Sheen Marine

[MarkSF]

"via switch (perhaps nav lights; you have these for night sailing when you need a compass light, correct?) and fuse or breaker from the house bank."

I think I would like to have separate breakers / switches for nav lights and instrument lights, for the simple reason that I don't want a fault in my instrument lights preventing use of the nav lights.