Compass basics... the lubber line.

[The Chairman]

Here is a more "indepth" discussion of declinations and inclinations: http://www.utm.utoronto.ca/~w3gibo/How to do field studies/properties_of_magnetic_field_at_.htm

 

[Mako Mark]

getting back to basics of why people have trouble with compass use underwater:

Common problems I have encountered are

Not holding the compass level

Trying to do the math for reciprocal courses and compass squares rather than using the index marks and the cardinal points.

Failing to account for current by using waypoint navigation.

Losing count of fin kicks during distance estimation.

Not writing down critical information such as initial headings, distances, depths etc.

Not knowing how to navigate around obstacles and regain their required track.

Not being able to apply this information to go and do a dive and navigate back to the boat or shore uw.

 

[Centerius]

Here's some more information on navigation.
http://www.mindspring.com/~divegeek/curnav.htm

 

[The Chairman]

Oh geez! THAT will scare them off quickly! The next installment will cover more about underwater navigation and you won't need your slide rule: I promise!

 

[rahuck]

Here's some more information on navigation.
http://www.mindspring.com/~divegeek/curnav.htm

I read about 10 words and developed this sharp shooting pain behind my right eye...glanced at a few of the 'vector' diagrams and the pain spread down through my shoulders into my chest cavity.

Being prudent...I stopped.

 

[Mako Mark]

Oh geez! THAT will scare them off quickly! The next installment will cover more about underwater navigation and you won't need your slide rule: I promise!

[mark extracts geeky pilot thingy that is impossible to use in a helicopter from his pocket and tries to hide it]

 

[The Chairman]

From the practical to the obtuse. Next we'll be calculating firing solutions so we can torpedo our dive boat. "Flood tube number 1!"

 

[The Kraken]

[mark extracts geeky pilot thingy that is impossible to use in a helicopter from his pocket and tries to hide it]

AMEN ! ! ! . . . if you're flying solo.

(As I reach over and pick mine up from the top of my desk. But mine's a Jeppesen/Sanderson)

the K

 

[D_B]

From the practical to the obtuse. Next we'll be calculating firing solutions so we can torpedo our dive boat. "Flood tube number 1!"

not our dive boat, the other dive boat .. Oh Looky a new wreck

Too funny cancun
And yep, lost track of # of fin kicks, writing down info,
Waypoints? ... on a featureless sandy bottom? ... thats another diver, right?
( in our case, you use depth/contour/slope )

Good info, for everyone ... you all have compasses ... don't you?

 

[The Kraken]

Another thing a person unfamiliar with compasses has to deal with, is the "lead" and "lag" when changing directions.

the K