# Deviation card /table?



## jackdale (Dec 1, 2008)

How many of you have a deviation card / table on your boat? I have sailed about 40 different boats. Four had deviation cards / tables. Yes, many of them had deviates on board too. ( I had to get that in first)

Jack


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## AdamLein (Nov 6, 2007)

In a binder with all sorts of documentation that came with the boat, I found an almost-totally-faded deviation card. I can't read some of the values. I've never sailed anywhere that I couldn't see where I was going, so even though we use the compass, we don't depend on it. When I wasn't sure, the GPS told me... some day I'll get around to making my own deviation card.

Also don't compasses usually have weak internal magnets that are placed to cancel out the deviation?


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## jackdale (Dec 1, 2008)

AdamLein said:


> Also don't compasses usually have weak internal magnets that are placed to cancel out the deviation?


The adjustment magnets can account for SOME deviation. After a compass compensator removes as much deviation as possible, they can then create the card.

Jack


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## jrd22 (Nov 14, 2000)

We had the compasses done and cards made on the last boat, haven't done the new boat yet, but will in near future. The compass is so much easier to use to steer a course when it's rough than a chartplotter.


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## Bene505 (Jul 31, 2008)

Flying we always had one. In a plane it's easy. You go to a runway that has special marks on the pavement in the shape of a circle. You taxi the plane into the circle at different angles and look at the compass, noting the needed corrections.

I ought to make one for our boat. Maybe the travel lift guy will shift around to 8 points of the compass and hold still, so I can get some accuracy? Probably not.

Good idea.


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## Maine Sail (Jan 6, 2003)

*Holy Crap!!!!!!!!!!!!*

I am amazed at the number of folks plying the waters without a properly calibrated compass and a deviation card!!!!

I have mine professionally calibrated every two seasons or any time I make an electronics change near my compass. Read the article in the link below and please find a professional to swing your compass!!!!!!!

I can guarantee that many of your compasses are off... way off!!!!!!!!!! Get them calibrated please!

Charlie is my compass guy and it's some of the best money I spend.

*Charlie Cook / Maine Compss Services (LINK)*

I guess we've become a point & click sailing forum.. Compass what's that???


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## tweitz (Apr 5, 2007)

You sure wouldn't want a compass deviation card made while on a travel lift, unless someone had a plastic or timber travellift.


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## AdamLein (Nov 6, 2007)

Maine, I appreciate the need for a proper deviation card in lots of situations, but I also suspect there are many sailors who are almost never in such situations. Day sailors in inland waters who never go out when there's a potential for fog, and carry a GPS... they've (we've) pretty much got it covered.

If I were to plan an extended trip I would certainly calibrate the compass first. I might do it anyway... just for the practice.


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## erps (Aug 2, 2006)

> I am amazed at the number of folks plying the waters without a properly calibrated compass and a deviation card!!!!
> 
> I have mine professionally calibrated every two seasons or any time I make an electronics change near my compass


Do you find that the deviation card changes much between your two season checks?


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## Bene505 (Jul 31, 2008)

tweitz said:


> You sure wouldn't want a compass deviation card made while on a travel lift, unless someone had a plastic or timber travellift.


Yes, it was a bit tongue in cheek. It would be a funny picture though.


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## Cruisingdad (Jul 21, 2006)

I give up. Which button is that on my GPS?

- CD


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## BlueWaterMD (Oct 19, 2006)

I just daysail and weekend in protected waters. I barely even use my compass.


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## SimonV (Jul 6, 2006)

Compass I have two of those, the one in the binoks needs a shake to work and the one at the helm is currently held in place with duct tape


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## Maine Sail (Jan 6, 2003)

erps said:


> Do you find that the deviation card changes much between your two season checks?


Yes it sometimes does but it is usually due to changes I've made in the cockpit. Also it is important to calibrate your compass to how you usually sail. For me I always have my plotter, depth and AP on. I actually have two deviations cards, an electronics on card and an electronics off card..


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## Maine Sail (Jan 6, 2003)

AdamLein said:


> Maine, I appreciate the need for a proper deviation card in lots of situations, but I also suspect there are many sailors who are almost never in such situations. Day sailors in inland waters who never go out when there's a potential for fog, and carry a GPS... they've (we've) pretty much got it covered.
> .


You're in BC. The last time I sailed up in that area I found the fog banks to appear just as they do in Maine from out of nowhere.

7:00 am beautiful crisp blue sky day
8:00 am NOAA confirms beautiful high pressure weather
9:00 am Sailing out of the Fox Isle Thorofare we see this








By 9:20 we were in pea soup for the next 5 hours.... I guess it depends where you sail. In Maine if you don't take navigation seriously you can get into big trouble!!


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## npronpro (Jun 22, 2008)

If you are going to stay in the same area - like Gulf coast of Florida, or the Bahamas - can you adjust your compass to "true" and then have it synched up with your GPS?

Rleated qustion - can you 'swing' the compass, moving to each heading using the GPS and adjust the compass; and then make a deviation chart?


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## johnferrell (Feb 1, 2009)

*swing compass*

You can use the GPS to swing the compass but you need to account for the local magnetic variation by setting your GPS to magnetic. If it only displays true heading you need to steer for the magnetic heading by adding or subtracting the magnetic variation. If west mag var add to the true heading and subtract if it is east mag var. i.e if you are trying to steer magnetic 0 and your mag var is 10 west you would sail 350 on the GPS. Adjsutments should be made at 90 then 180 then half of the the error at 270 and 0. then swing every thirty degree and record the differnce between your magnetic heading and the heading on the compass--this would be your deviation.


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## CaptainForce (Jan 1, 2006)

We used to cruise over to the Bahamas before the time of GPS with dead rekoning and a RDF. I had made a deviation card, but stopped using it and instead I would take a pelorus to the bow and call out a mark for the helmsman to note the heading on the binnacle compass. I know there could be some cause for deviation at the bow for some vessels, but I had negligible effects on my boat and this plan always gave us a course that was successful. 'take care and joy, Aythya crew


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## sahara (Dec 15, 2006)

I keep my boat at a well known boatyard in SW Harbor, Maine. Last year I had new electronics installed at the helm, and when I got on board for the first time in the spring, there was a new deviation card sitting on the nav station. I never have to ask them for this, they just do as part of the routine of properly preparing a boat for cruising. IMO, their reputation for excellence is well deserved.


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## pukeslip (Apr 27, 2009)

deleted


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## jackdale (Dec 1, 2008)

Maine Sail said:


> Yes it sometimes does but it is usually due to changes I've made in the cockpit. Also it is important to calibrate your compass to how you usually sail. For me I always have my plotter, depth and AP on. I actually have two deviations cards, an electronics on card and an electronics off card..


Interesting ... How different are they? Could you scan and post them?

Jack


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## Henry Irla (Aug 3, 2011)

*obsolescense*

What's the use of it (dev. table) on the days of the GPS?


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## wolfenzee (Jul 13, 2008)

Until recently my sailing was local and I recognized enough so any deviation was insignificant( the compass that came with the boat wasn't so hot either. .But have recently purchased a Richie Globe master, bronze binnacle and am having a brass compass guard made, all will the intention of serious ocean trips...once installed I will have it adjusted properly


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## jackdale (Dec 1, 2008)

wolfenzee said:


> Until recently my sailing was local and I recognized enough so any deviation was insignificant( the compass that came with the boat wasn't so hot either. .But have recently purchased a Richie Globe master, bronze binnacle and am having a brass compass guard made, all will the intention of serious ocean trips...once installed I will have it adjusted properly


Deviation has nothing to with where you sail.

Deviants may have to do with whom you sail.


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## AdamLein (Nov 6, 2007)

jackdale said:


> Deviation has nothing to with where you sail.


I think his point was that he didn't do any navigation by compass, since he could easily do all of his navigation by landmarks.


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## jackdale (Dec 1, 2008)

AdamLein said:


> I think his point was that he didn't do any navigation by compass, since he could easily do all of his navigation by landmarks.


Very possible in the PNW.


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## Capt Len (Oct 9, 2011)

The compass formation by GPS is calculated internally from information like positions over time.It tells you where you've been.and you assume it's pointing the way you're going. Accidental in irons, gybe, MOB or maneuvering in fog and rocks and dark with current will show the short comings of not having a ""trusted ""compass .Before GPS I'd set my course by wave action and guesstimate my way across the Beaufort because compass was useless in rough weather (too far north) Understanding dev ,var, dec and error can save your butt.


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## LetsGetWet (Sep 29, 2017)

Once I get to the edge of the continent, definitely. Not much use on the lake.....


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