Compass

[happy daze john in oz]

On our last cruise I met with a guy who had a table in our section of the restaurant all to himself. He became very friendly over the two weeks and he indicated he had spent some time with Blue Funnel back in the 70's, though he did not elaborate. Over the evenings I learned that he spends most of his life cruising, which for a man in his 50's by the look of him means money or the know how. On average about six to seven a year, some up to six weeks. He had just completed two previous ones on this ship and comments from the head waiter were that ,'we treat him as one of the crew'.
He had a lot of influence with various members of the catering crew it appeared, often having special dishes served to him. Through his friendship I was able to indulge in some of them my self.
On the final night he gave me his business card on which his title is,

SHIPS MAGNETIC COMPASS ADJUSTER (AMSA Licensed)

He never spoke of this but did tell me he did a lot of time in computer programing.
From the title on his card I assume he has something to do with the accuracy of the ships compass. I know there is one on each life boat, but why would he need to spend so much time on any one ship just to ensure the compass is correct.

Maybe Captain Kong or others can enlighten me on this one?

[Captain Kong]

Hi John
was he on there in his official capacity as Compass Adjuster of did he just have a few bob in his bank , single and enjoying himself.
Usually in my experience after a ship has been in Dry Dock the first job during sea trials the Compass Adjuster swings the ship in various positions taking bearings and so on. and checks the Magnetic compasses for Deviation, against True bearings. The ship itself is a big bar magnet, and say four weeks or so in a dock can affect the magetism in the ship and compass.especially if any steel work has been done.
That is just a simple way of explanation. A little more detailed in its operation.Then the ship is issued with a Certificate. I have never heard of one making several voyages on a ship.
Maybe some more of our intrepid Navigators can elaborate on this. I have been retired for 18 years.

[Capt Bill Davies]

Good morning John,

With respect to compasses what you have to remember is that whenever a ship gets built it assumes the characteristics of a magnet itself. Shipyards around the world used to be built with their orientation in a certain direction to reduced the effects. Too earlier in the morning to go into coefficients or ‘splitting B’.

Sufficient to say that when you transport a compass aboard a ship (steel) it will react differently than it did when you had it ashore. You now have to think that the compass is being effected by the huge magnet the compass is sitting on (the ship)
With this in mind it is clear to understand that there will be a’deflection’ of the compass needle as it is drawn to parts of the vessel whose characterists have seeking qualities (beaten into the ship during the building process).

The Compass Adjusters job is to correct this deflection.

It is an ongoing process throughout the ships life. Further certain cargoes, Iron Ore et al, will have a big effect on the compass.


Business cards, what are they?

Brgds

Bill

[Bob Hollis]

Hi John,

Here is a link giving a simplified version of what his profession is about, in practice it can take quite a long time. I was on the Gothic on the voyage after the fire and we only had a magnetic compass, one fine night the helmsman, bored, on discovering the corrector balls were not tightened he unscrewed them and decided to roll them on the deck. With this and other anomalies taking place it gave the old man, Captain Brian Agnew, a great chore in correcting the compass.

Navis.gr - How to apply the Compass Error

[j.sabourn]

Re Bob Hollis re helmsman. Bob was he that bored that he had to play with Lord Kelvins Balls, what was wrong with his own. Cheers John Sabourn

[John Cassels]

Morning Bill , perhaps you should have had a cup of coefficient B first !.

[Capt Bill Davies]

Morning John,

I sometimes think it might help.

[Bob Hollis]

Re Bob Hollis re helmsman. Bob was he that bored that he had to play with Lord Kelvins Balls, what was wrong with his own. Cheers John Sabourn

John, I think the Old Man would have liked to have played with them.lol

[Capt Bill Davies]

Whilst I used to think nothing about correcting compasses myself and did so on hundreds of occasions I was aware that Japanese mates were in awe of this art. I was never sure whether there syllabus was weak on this topic as they excelled in all other aspects of nautical proficiency. The Japanese ships I sailed in and those built in Japan for US account all carried Gyro's inxs of class requirements. Two, three Master Gyro's were not uncommon.
Having said that, the Japanese Compass Adjusters were probably the most thorough you could find and exceeded the average age of the Pilots which was generally 60+ They were OLD.

[John Arton]

Hi all
Despite what certain navigators might think, the magnetic compass is still a very important part of the ships navigational equipment and it is still mandatory to have one on every ship, however many gyro compass's there are.
In the tanker industry all the various vetting bodies are placing great importance on tankers having properly adjusted magnetic compass's and who betide any captain who has a deviation card older than 12 months, signed by a recognised compass adjuster.
rgds
Captain John Arton (ret'd)