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Upside down compass

Discussion in 'Basic Scuba' started by Pseudocyber, May 30, 2010.

  1. Pseudocyber

    Pseudocyber Contributor

    # of Dives: 50 - 99
    Location: Charlotte, North Carolina, United States
    111
    6
    I just bought my first scuba compass - opting for a retractable one, with a small slate on the back.

    Looking at it at home, I just realized the numbers are upside down. North is 180 degrees and South is 0.

    I thought this was defective - and began googling other scuba compasses - and it seems they're all upside down.

    I'm an old Eagle Scout - and like to think I can do basic orienteering - but I cannot come up with a reason why scuba compasses would have North as 180 degrees.

    I'm sure there's an answer that makes sense - and I'm a NewB for asking - please explain it to me.

    Thanks,

    PC
     
  2. elmer fudd

    elmer fudd Solo Diver

    # of Dives: 200 - 499
    Location: Puget Sound
    1,094
    124
    The numbers are visible from the viewing window in the rear of the compass. So if you are facing North, the needle will point to the N and if you look through the viewing window you will see 0.
     
  3. Bonairetrip

    Bonairetrip Solo Diver

    351
    18
    And, IIRC, the numbers on top will then be your reciprocal bearing...
     
  4. Firefyter

    Firefyter Solo Diver

    # of Dives:
    Location: NE Texas
    1,781
    53
    The numbers on scuba compasses aren't backwards.......it's the rest of the world that's backwards :cool2:
     
  5. Doc

    Doc Was RoatanMan

    # of Dives: None - Not Certified
    Location: Chicago & O'Hare heading thru TSA 5x per year
    10,124
    2,994
    The retractable thingie will kill'ya deader than Nixon. I know, I read it on the nets.

    It's not backwards, just ready for the coming polarity reversal. Geomagnetic reversal - Wikipedia, the free encyclopedia
     
  6. ajduplessis

    ajduplessis Solo Diver

    # of Dives: I'm a Fish!
    Location: dry land :-(
    3,256
    836
    Upside down, must be an Australian compass!! :D
     
  7. Garrobo

    Garrobo Contributor

    # of Dives: 200 - 499
    Location: Ohio
    3,226
    201
    I figured Chinese since they are on the other side of the world. Probably work OK down there.
     
  8. Pseudocyber

    Pseudocyber Contributor

    # of Dives: 50 - 99
    Location: Charlotte, North Carolina, United States
    111
    6
    Funny guys. :)

    I get the looking through the window and seeing the bearing of 0, as I swim due north - but I would think looking down on the compass and seeing a bearing of 180 - or some other odd angle would get confusing over a couple of turns - I'm surprised manufacturer's think the number in the window is more important than the numbers when looking down on the face of the compass.
     
  9. maged_mmh

    maged_mmh Instructor, Scuba

    # of Dives: 100 - 199
    Location: Egypt
    3,421
    7
    srsly, we (I?) look 'over' the compass, rather that down on it; hence the window usefulness :wink:
     
  10. eponym

    eponym Master Instructor

    # of Dives: 1,000 - 2,499
    Location: Oregon, USA
    1,608
    257
    I think I see what you're asking.

    When I'm looking down on the compass I can see the magnetic arrow. If the pointy (N) end of the arrow is pointing forward (aligned with the lubber line), I'm going North. The numbers around the edge of the rotating card mean nothing to me, I don't even notice them. Never have. Really.

    What I do notice is the numbers on the rotating bezel. If I'm attempting to swim a given course then I've rotated the bezel to the correct setting and all I have to do is keep the N end of the needle in the twin pins ("keep Nate in the Gate" as I was taught) and swim by the lubber line.

    Hope this helps,
    Bryan

    PS. I almost never use the side-view feature. Requires more close-up vision than I have left.
     

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