I need a new compass...-gctid385774

[Jeffw]

...and would welcome suggestions or advice. I had to remove the old one from it's nice spot on the flybridge, as that was the only place to mount my new VHF radio. The only requirements are that it's reliable, on a gimbal mount and is lighted. Thanks in advance...

[BLCarl]

I also would like a better compass.

My dilemma is that most are not very accurate due to where they are mounted and do not repeat in some directions. I do have too much iron in and around the helm so that's more of the problem than the compass itself. I did get a hand held to cross check the built in but it only confirmed the situation. Even a hand held goes goofey as I move around my 24' yacht. Too close the engine or something else changes the heading. My heading standing on the dock is different than on the boat and even that may be a issue of steel in the dock. I'm not sure how it they work but a electronic compass might be a answer for me. I supose if some GPS heading is the correct direction even though the numbers don't agree on the magnetic compass it's good enough to hold a corse to your destination. I find the analog dial of a magnetic compass much easier to follow than thinking and reacting to digital numbers.

[captharv]

The compass is the most mis-understood device aboard a boat; the anchor is second.

I taught marine navigation for the CG auxiliary as a member course, and later 16 times at a comumity college.

We used to go out 20-30 miles fishing, troll for 2-3 hours,a nd come back to port before LORAN and GPS. Never got lost.

I have a Richie D-84 on my 2452. The one which came with it was a deck ornament, as it was too small (read--cheap) to navigate with.

What money buys in a compass.

Not accuracy. They ALL work by a magnet which lines up to what it thinks is a magnetic line of force on the earth. Money buys:

1. Better damping. So whemn you are busting thru 2-4' seas, it retains a steady reading.

2. Smoothness. Better ones use a jewel such as the expensive swiss watches used to use. Sorth of their version of ball bearing.

3. size. dials are easier to read, hence the easier you can steer a course

4. reliability; Money buys better built so ut will not try tp disintegrate in heavy weather.

Mount it below eye level, so while running, you can merely shiftyour line of sight to read it.

Cards--two types

1.direct reading. Use this ONLY if you cannot mount it so it is under youir sight plane and you must read the front. look at a compass dial on a chart. North is up. East to the right, west, left.On a front reading card, east is to teh left of north. So if you are going 090 and want to go 100*, the card has 100 to teh left of 090. Howevr, you must turn the wheel to thr right to do it. See what I mean? confusing to an EXPERIENCED helmsman.

2.flat card. On this, you look at the back of the card. Not only is the card laid out as a compass rose on a chart, but the looking thru the fluid magnifies the back of the card, thus further enhancing reading it, especially when not in flat calm.

(Thats why I bought the D-84)

Now that you have one, hear this: the inacuracies caused from on the boat thingiescalled deviation, is a fact of life. You cannot adjust it out using the "compensating magnets". I tried this many times. If you get it all out, its just plain dumb luck. Besides, if it did, there would be errors introduced as the boat rocks or pitches even in light weather, because the distance between the compensators and the card magnet is constantly changing.

The answer is to make a deviation table. How?

If you have a GPS, program it for "magnetic" or "automatically determine variation ( the earths error system). The, on the companss run 000*, carefully, at whatever cruising speed you do. Write down the difference between GPS and 000. It is important to include + and -.

repeat thsi every 30*. Then make up a chart.

A bit harder w/o a GPS, and a lot more immportant to be correct. On a chart, locate objects that you can recognize both on teh chart and by eye. ployt their true course and write it and magnetic with a pencil. Locate enought to adaquately cover teh compass rose. 30* or so. Then, run between teh objects and record the course steered on teh compass. add or subtract as nedded and make a compass dev chart

Now, with the chart, lets say you want to go 090 true. Add/subtract the variation from the chart.

add/subtract the deviation. On my boat 090T 5*W (add) is 095 Magnetic. Deviation at that heading is 4W giving 099 compass (or PSC per ships compass)

raed the Chapmans book on compasses

[Guest]

Captharv has some good advice.

A mention was made regarding electronic compasses. I have one, the Azimuth on the bridge. It is pricey but it was well worth it to me. My boat is 38'MY and there is another compass at the lower station, a Ritchie not sure of the model (it is an older compass) and about 6.5" similar to the Navigator DNP-200 sold by West Marine.

A compass is vital to me and I would pay as much as I could afford for a Magnetic compass like Captharv described. Electronics are nice but what happens if you lose the electronics? If you only need one go magnetic and refer to Chapmans for how to use as suggested by Captharv.

Richard

[dmcb]

I am in the process of fine tuning my deviation chart. With a GPS, its pretty easy.

For those with a lower helm, when you think you have everything figured out, turn on your windshield wipers and see what happens.

It isn't just metal, its electronics. Speakers have magnets for example. Your radio has speakers.

I have an old Danforth Constellation I have had for many years and on several boats.

A good older compass on Ebay would be a better one than many you can buy today.

Here is a beauty if you have room for it. The 24 volt is just the light bulb.

http://www.ebay.com/itm/NEW-EXPRESS-DANFORTH-MODEL-C-458-CONSTELLATION-COMPASS-24V-/251070056924?hash=item3a74f109dc&item=251070056924&pt=Boat_Parts_Accessories_Gear&vxp=mtr

This is like mine.

http://www.ebay.com/itm/DANFORTH-5-CONSTELLATION-EXPRESS-COMPASS-BINNACLE-/310373777018?hash=item4843b7fe7a&item=310373777018&pt=Boat_Parts_Accessories_Gear&vxp=mtr

[Jeffw]

Thanks for the replies...