The Compass Adjusters Tale
As a result of being appointed Navigator to a new Castle Class Corvette built at Fleming & Fergusons yard at Paisley, during the war, I became friendly with the Admiralty Compass Adjuster working on the Clyde.
My friend was naturally being kept very busy with the steady stream of new naval vessels coming out of the thirty or so yards, which then existed on the river.
Most of these ships were more or less manned by newly trained civilians who were about to learn a lot, in a very short time.
For those unfamiliar with the details, the job of the Compass Adjuster is to try to eliminate as much as possible, the effect of the ships own inherent magnetism, on the magnetic compasses, so that they point as nearly as possible towards magnetic north.
In practice this is not completely possible, so that when he has done his best, he draws up a Deviation Card which shows how much allowance has to be made for compass deflection, for any particular heading.
He counters the magnetism of the ship by setting up a contrary field around the compass using two soft iron spheres, one on either side of the side of the binnacle (Quadrantal Correctors), and for those forces acting on the vertical soft iron by placing vertical soft iron in the brass tube on the fore side of the binnacle (Flinders Bar).
In addition he opens up the binnacle, which is honeycombed with holes, and makes further fine adjustments with small bar magnets which are placed in the holes, and left there permanently. These magnets are supplied to a new ship in a special cardboard box, and generally handed to the Navigator for safe keeping.
While the compasses are being adjusted, the ship is swung around a buoy by a tug, so that the adjuster can adjust for all headings. The adjuster works with (or did in those days) the ships Navigator, who assists him as required, and who is naturally interested in what is going on.
Some ships were easy and could be dealt with in a couple of hours, others were complete cows, or as we rude sailors could occasionally be heard to mutter (not of course out loud) utter sods, and could take hours and hours of frustrating work.
On this particular occasion the ship in question was a particularly bad example of the latter. Round and round the buoy it went and as fast as the E - W deflection was ironed out a huge N - S one would appear.
The ships Navigator, a smooth faced Solicitors Articled Clerk, fresh from King Alfred, gradually began to loose his enthusiasm for his work and by the third hour it was clear that his mind was on other matters.
Finally after about twelve weary hours my friend was satisfied with his work. Staggering to the back of the bridge for a fag, he said as he went, "OK Pilot, you can pack it all up now".
Unfortunate choice of words!
When he turned round he saw the Navigator taking the magnets out of the binnacle and packing them away in the cardboard box.
By Paul Bell (old RNR)
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hi a bit late but i have just acquired a heeling errow instrument,couls you advise on how it was used,and could you say hello to my brother-in-law colin krogh,he's somewhere in Townsville
Capt. Raymond Pincot
I am a licenced compass adjuster in Townsville, Queensland, Australia. I am trying to find a 'Vertical Force Instrument' also known as a 'Heeling Error Instrument' used in compass adjusting. These instruments have been taken into maritime collections by collectors and have caused a shortage of this necessary instrument in the trade of compass adjusting. I am presenting a paper at a marine confrence in May 2008 about the magnetic compass and would appreciate any stories about the subject from any one who would like to contact me.
Capt. Ajit Nair
I would be glad to know from someone, the procedures for adjusting a compass on board merchamt ships currently being used by adjusters other than conventional swinging of the vessel.
My fater in law recently deceased, left me a "sirius"/"deadmans" compass.I have assisted him a number of times with an adjustment but I was just the arms and legs. Is there a sight anyone can suggest I go to for a greater understanding of the process.This "sirius" adjustment instrument stands approx 3 ft on a tripod and is made fo very heavy brass and has sights which are used to kine up distant predetermined location.I can be contacted at,firstname.lastname@example.org
On many vessels I would not be surprised to see a large DVD player screen( for entertainment)) in front of the Helmsman instead of a compass!
I have just installed a Ritchie compass beside a Lowrance Dual fishfinder GPS plotter in my Runabout. Can anyone tell me if I can use the projected Magnetic bearings on the Local plotter chart to check the Compass bearings M as I swing the boat around on the trailer?
Morry New Zealand
Ian L. Moist
I began my career in 1963 in the British Merchant Marine. In 1975 I was understanding the vagaries of magnetic compasses, the various coefficients and compass correcting as part of Master Mariner F.G. which I passed that year.
It makes you wonder if the level of competence is being maintained, as it was in Blighty then, or wether the advent of GPS - Sat Nav - Gyros and High Tech Nav Aids has removed the need to thouroughly know, that which is now locked into a manufacturer's system.
With the passing of time, I believe that the magnetic compass in the Master Mariner Class 1 syllabus may even be removed altogether.
Ian L. Moist Christmas Island Aus.
Ole M. Ronning Norw
Interesting article, I am an compass adjuster in Norway, and some of the problems seems well known, still today with Gyro and Satelite compasses, the old magnetic still has to be fitted, and adjusted today. We do not use Flinders bar, since this has little effect on high lattitude ( 70.40N but the rest is still in use.
It is a pitty that none of the navigators today seems to know how to adjust their own compass, not even make a deivation list.
Ole M. Ronning
i HAVE A JOHN HAND 7sons compass in a brass case in mint condition would anybody be interested/ IF SO PLEASE CNTACT ME
Is it that long ago that I visited your website, I will put it in my favourites as the "art and science" of compass adjustment is probably a fading one and I don't know of a website where the learned folk can go and write to each other. In reply to Nick Bending's email of 14/10/03, the method of compass adjustment is exactly the same as that in the article, nothing has changed. I do know from our studies that during the war de-gaussing coils were fitted to merchant vessels and it was necessary for the adjuster to check the effect of the various electrical current settings at the binnacle. I served on British Ships during the 70's as a young second mate, the company was "The Bank Line" and they still had de-gaussing equipment on them. I was told that the company had a policy of retaining this anti-mine equipment so that in the event of conflict, the British Govt. would select their vessels for charter first. Best wishes, John Shanahan, Compass Adjuster in Tasmania, Aust
June 2003, at my arrival at one merchant vessel the master advise me,there is a big problem,when I was ready for adjust the compass, i saw there not was the quadrantal spheres, the captain begin the investigations, was at the room of one cadet (from first year) used for exercises as per an weight.
Bill O'Sullivan KB4U
I can understand how that adjuster felt
as I have provided the same service on many ships & small craft - generally we are allowed about 1 or 2 hrs. to complete a compass swing and if not completed it's a long swim ashore -
best wishes, Bill O'Sullivan
compass adjuster & repairs @
O'Sullivan Marine in Virginia, USA
Very interesting but i have a Question. Is the method you use today the same as that used by Airy or is it different? Can anyone help?
12 hours for the adjustment - some record. Sometimes I go home and think about a problem and have a second shot at the adjustment but to battle for that length of time!! I often go on a ship and the corrector magnets, pelorus and Flinders Bar pieces are nowhere to be found so like your story, the navigator, these days the Second Mate on a Merchant Ship, often packs the residue of gear away after adjustment and it's never seen again. Thanks for your story. John. Compass adjuster in Tasmania, Australia.