Compass Problems in Quarry? (Pearl Lake, IL)

[cam]

Hi All-

Anyone ever run into problems with compass navigation in a quarry before?  I was practicing the nav drill on shore for our OW class with my buddies but we kept getting mixed up.  The drill was to start from one location, do ten paces out, then reorient the compass to return to the original location.  One by one, each of us returned to a different spot, even with the coaching of the instructor.  ???

Then it dawned on us that the mineral content of the quarry might be throwing off magnetic north for the compass.

Anyone else experience this or can offer another explanation?

Thanks!

[Dewit2it]

Not in a quarry...yet!  I have had a lot of problems with compasses up at Munising.  Diving the pillings, I've seen the compass card dipping toward the bottom with the compass level.  But it will work fine on the surface.  Also had some fun out by the Herman Hetler, and have heard reports of problems by the Selvic.  We tried doing a course at the pillings for one of Inland Seas' advanced courses and everyone got lost, so I wasn't the only one having problems there.  They stopped doing them there when even the instructor had problems.

[Nate]

Pearl Lake? That was an old SAND quarry. I would'nt think sand would throw off your readings. Maybe if it was an iron quarry you might have slight problems.

[jeffberry]

  Seen that in lake Wazze a few times.  This year I had 2 SK7's go bad. They both locked up.  Sunto has a good warrenty

[jmohns]

I have had issues in Wazee near the Sherwood Forrest area, my compass acted drunk and would make drastic changes even if you only moved a few degrees. It was very aggravating for the newer diver trying to learn how to use the darn thing (me). I purchased the book available at the guard shack and it tells you to not believe your compass in may parts of that mine due to the iron ore content. BUT.... I have dove in Pearl quite a bit and aside from my own inexperience, I have had no issues unless I was next to the sub or such. James