Compass Question No. 2 -- Best type of compass for a C Dory?

[sketchrbob]

I'll start this off by saying the answer is probably -- the one you are using right now (assuming you do have a compass).

The reason for this is that you are used to it and probably comfortable with it. If it does the job and you can read it easily there is no need to change. I do not know what compasses were originally supplied with C Dory but my guess would be a Ritchie model - either a Helmsman or Voyager in either a flush mount or a deck mount. The Helmsman has a 3 3/4" card while the Voyager has a 3" card. These are both fine compasses, but older eyes get tired and the larger card is definitely helpful.

So about the only time you will need to decide about a compass is when you trade boats and do not like the compass that came with it, or when the repairs to your present compass would cost as much as a new compass. For this reason always get an estimate on repair cost.

When the time comes when you need to make a selection it can be confusing because there are so many choices. Flat Top or Dome Top? Which manufacturer? What size? Direct Read or Open Face card? Flush Mount or Deck Mount? Hi-Speed or Standard? Magnetic or Flux Gate? Many of these choices are a matter of personal preference. However, since I have adjusted hundreds of compasses, I am often asked what my personal choice would be.

I must admit that I am prejudiced in favor of Ritchie compasses. I sold Danforths, Dirigos, Rivieras (an Italian compass) and Ritchies. The Ritchies always impressed me with the quality of parts, ease of repair, the wide choice of models, and the integrity of the company organization.

However, there is a basic difference between the Danforths and Ritchies. The Ritchies are a little more sensitive than the Danforths. This means that the Danforths do not take as long to "settle out" when coming to a new course. The Ritchies on the other hand will be quicker to follow minor course changes. This is due to the lighter weight of the aluminum card of the Ritchie -- which incidentally does not wear the jewel and pivot as rapidly. Actually I think mostl people would not notice the difference between the two compasses unless it was pointed out to them.

Next, I favor the open face card over the "Direct Read" card which is like the old automobile compass. Again this is a matter of personal preference. If you cannot decide, they now make combo cards that can be read either way.

Third, I like a binnacle or "deck" mount compass where the whole compass sits above the dash board. This compass has its whole "guts" up in the open. I have seen too many compasses of the flush mount variety with their magnetic systems below deck and very close to magnetic fields from radio speakers, wiring circuits, steering pumps and fire extinguishers. People often disturb a perfectly adjusted compass by adding some of these items without a thought to the compass. Further the deck mount compass is so much easier to adjust, as the correcting screws are easy to access. The flush mounts have to be put in and taken out every time a small adjustment is made.

C Dorys will function just fine with a standard card and do not need the larger magnets or heavier oil of the Hi-Speed card. Of course I do admit that the Hi Speed card may impress your guests!

Spherical Dome compasses have magnification that make the numbers easier to read than Flat Tops. However, if you are more comfortable with a Flat Top got with that.

How big a compass? Get the largest compass that you have space for and can afford. I used to tell my customers, "Just because you have a small boat, doesn't mean you have small eyes."


What about Flux Gate compasses? At something over twice the price of the Ritchie Helmsman the KVH flux gate is a digital compass that can be bought as an "all in one" unit or with a separate sensor that can be mounted away from all magnetic interference. The flux gates are still affected by magnetic influence but can be easily adjusted often by making three slow circles. The use of GPS has greatly cut into the use of the flux gates. Many people say "How many back-ups do I really need?

So my choice for a C Dory would be a Ritchie 3 3/4" Helmsman, Open Face Card, Deck Mount , Standard Speed Oh yes, you often have a choice of colors on the card, black, white, red, or blue. Personal choice I would choose black. I had a white card on my compass at one time and found that it often reflected light which was annoying.

So that brings us in full circle and I suspect it is the compass many of you already have!

Ok Guys and Gals, I hope I have given you enought to chew on. What are your thoughts? Bob W

[oldgrowth]

Bob – thank you for a very informative post on the different types of compasses. Next time I have to buy a boat compass, I will have a better idea of what to look for.


Dave
www.marinautboats.com

[teflonmom]

Several years ago I was active in the Power Squardern. Each year they held nav. contests. It was nessary to get a deviation chart for your boat and compass. I always made mine useing the GPS. There must be a better way. That being said one year I did manage to win first place. It was very rough that day and keeping the 22 foot C-Dory steady was quite a project. I suspect luck played a part in the win.

Perhaps you could help with some instruction.

[CAVU]

A few year ago I posted a question about using the compass and GPS for navigation. I was surprised that many members don't have or don't use a compass. I am a firm believer but maybe the first question should be: Do you need a compass?

[Forty Two]

Steer clear of the Tate compass.

Because he who has a Tate's is lost.




Sorry - old joke, couldn't resist.

[Captains Cat]

[hambone]

[sketchrbob]

I hear your questions. When I set up this post, it seemed logical to divide the many questions owners have into categories. Hence the series of questions. I just posted another item under General Chat "New Compass Question Posted". This refers everyone to this section under "Electronics". It also refers you to a post under General Chat "Compass Questions" where all the 11 questions are listed.

Here you will see that all of your questions which you are asking under this weeks topic will be covered in future weeks discussions. Your questions are good ones and I assure you we will cover them all. In fact if you stay with me you will learn more than you ever wanted to know about compasses.

Incidentally, if you want to see pictures and specs of any of the compasses I talked about in this week's question you can go to the catalogs of Ritchie, Danforth, KVH, and Hamilton Marine -- all are on line

Incidentally, Hambone, a few years ago, I was adjusting a compass for The Maine Island Institute at Rockland. The boat was an aluminum open boat about 18'. A young lady who looked to be in her late teens brought the boat with a pick up truck and launched it herself - very capable. The boat was being used among Maine's islands and obviously needed a good adjusted compass.

We went out into the harbor a way and commenced doing the adjustment. This involved running multiple courses in all directions. Just about the time we finished. the fog shut down like a window shade. We could hardly see one end of the boat from the other. And we had no idea where the launching ramp was.

Well I reasoned that we were on the Atlantic side of the continent, and that no matter where you were land had to be to west of where we were. So we headed due West. And in a very few minutes we saw the launching ramp dead ahead! So you see, as long as you know which side of the continent you are on, you should be able to find land!

Keep your questions coming! Bob W.

[rogerbum]

I don't have a compass on my Tomcat (other than a small hand held) and did the same on my CD-22. However, I have a fixed mount GPS, a battery operated handheld gps, a gps in my phone with Navionics software on it, and a gps in an iPad with Navionics software on it. My co-owner also has a GPS in his phone with Navionics software on it and another iPad with Navionics software on it. So that means on a typical trip we have 6 GPS on board and all run off of independent batteries. So, I'm not worried about getting home if "all else fails". In fact (as I've said many times before), "if all else fails" is likely to be caused by the electric magnetic pulses from a series of nuclear bombs and I don't want to get home - I'm fishing until I die of radiation poisoning .

But seriously, I think that the navigational need for a compass is not rational in this modern age. HOWEVER, the compass is useful to keep the boat pointing in a given direction or to chose a new direction of travel when one is traveling at low speed (during which time the GPS cannot provide accurate direction information). It's also useful if your radar/GPS isn't hooked to a flux gate compass so that they properly overlay AND if you're again a low speed over the ground. In such a situation, the radar image will coincide with where the boat is pointing but the map on the GPS won't. As a result, you won't be able to distinguish a buoy which you are drifting towards in the fog from a small boat coming towards you. So in sum, I think there are some very good reasons to have a compass on board but as long as you are in a power boat (which can travel at speeds well above prevailing currents) AND as long as you have redundant GPS's, the reasons have little to do with navigation.

[Wandering Sagebrush]

[Captains Cat]

[tpbrady]

Last weekend was the first time, I used almost every navigation tool on the boat. We left with about 2 hours of usable daylight for a 1.5 hour trip. We went from calm winds to cloudy and rain, then fog with 1/4 mile and 3 foot seas. I had the radar on at 3/4 mile range, the chartplotter running on a separate screen with the helm running on autopilot. Everything was going well at 16 mph until I had to decouple the autopilot so I could avoid a log in the water. As I was steering back to course, looking at the GPS I realized I was all over the place since it wasn't updating fast enough. Finally, I realized I should really use the compass to come back to bearing and then engage the autopilot.

That problem solved, it starting getting dark, so we slowed down to 7 mph, using the radar to verify the position of known rocks (low tide), the chartplotter, to be sure the projected course was clear of rocks, and the compass to be sure the gps wasn't getting lost.

Yes, I think a compass is required, especially at night, in the fog no matter what electronics you have.

[Plan C]

I got tired of giving up dashboard real estate to a Ritchie compass that I didn't use. I pulled it out and bought a Suunto hand held sighting compass. It is very small, high quality, portable. More than compass, it gives you accurate directional readings. I use it only a small amount more than the Ritchie, but it is zero inconvenience. If I still had the Ritchie, I would still want the Suunto.

Dave

[DaveS]

Hi Bob,
I've been reading all of the postings that you have so generously shared with all of us. Thank you. For some time I've been meaning to share the information about the compass on board our 22' C-Dory, but until this morning I kept forgetting to double check the brand name of our compass.

When we ordered our C-Dory thru Les and Kathy at EQ Marine, Les and I had a discussion about what compass might be best at that time for our usage. Since there really is no "great" place for mounting a compass that is the "2 foot or greater" distance from electronics etc. that have a tendency to interfere with compass accuracy on the 22' C-Dory, Les suggested the following which I like.

The compass is a Ritchie compass that has a quick release from its' mounting spot near the center window. This provides the ability to remove the compass from its' mount and utilize it as a "handheld compass" and thereby moved away from any potentially interfering electronics, speakers etc. Obviously, a user would have to remember to remove the c-phone, knives, flashlights, and magnets from their belt, pockets, PFD's etc. Additionally, if an individual were to dinghy in to a remote location from an anchorage, the compass could accompany the individual on his shore venture.

Like most others on the site, I rely upon my GPS and Chartplotter, but it is good to know that the compass is there if needed.

[sketchrbob]

Hi Dave S, I think the spot near the center window may be the best place for your compass. You may find that it checks out fine with the adjustment process. I will be posting that at this location next Thursday. If you have any problems you can send me a message. Good Luck! Bob W.