Compass issues

[Keith.M]

A compass needle does not need to move for you to veer off.

Other than current, how does this happen?

 

[cascas]

Other than current, how does this happen?

Right leg stronger than left. Uneven drag left and right. For starters.

 

[dmoore19]

Come on, it's a compass, it isn't GPS.

 

[Akimbo]

Come on, it's a compass, it isn't GPS.

True, but a compass is all you have underwater. I never really bothered to get all that good at it once I realized how much continuous concentration and personal training is required to be reliably closer than about 20° over a few hundred meters... especially in a kelp forest.

 

[AfterDark]

A compass needle does not need to move for you to veer off.

Well sure if the user is holding it off level the needle won't move at all even if the user is swimming in a circle.

---------- Post added October 4th, 2014 at 05:53 PM ----------

Right leg stronger than left. Uneven drag left and right. For starters.

Just so happens my right leg is a lot stronger and bigger than my left and my left leg is shorter than my right. I must compensate without knowing it.

 

[redacted]

Well sure if the user is holding it off level the needle won't move at all even if the user is swimming in a circle.

---------- Post added October 4th, 2014 at 05:53 PM ----------




Just so happens my right leg is a lot stronger and bigger than my left and my left leg is shorter than my right. I must compensate without knowing it.

Have you ever tried to swim a straight line with no visual reference? I'm definitely going to be swimming in a circle. That means, if I am not paying pretty close attention when following the needle (different from picking visible way points), I can introduce a bias. Nothing really wrong with some error, left and right, as long as they mostly balance. Practice can really pay off in this area.

 

[AfterDark]

Have you ever tried to swim a straight line with no visual reference? I'm definitely going to be swimming in a circle. That means, if I am not paying pretty close attention when following the needle (different from picking visible way points), I can introduce a bias. Nothing really wrong with some error, left and right, as long as they mostly balance. Practice can really pay off in this area.

You mean like I do when night diving? The compass is my reference, like my depth is my reference at night when I ascend. I've had lots of compass practice, decades on land and underwater. Being off 15 20 deg on a 100 yd swim isn't too bad, ya end up pretty close to where ya want. I'm no Navy SEAL after all.

 

[scuba5150]

I bought a Suunto compass based on the recommendation of my AOW instructor and have been very happy with it. The card floats in the housing with enough free space so that it's not as sensitive to minor tilting. They claim it can tilt up to 30 degrees and still be accurate. I wouldn't be comfortable with that much tilt, but minor tilting doesn't seem to affect mine.
E.g.

Suunto SK7 End Mount & Console Back Mount Compass 186570 with reviews at scuba.com

 

[Storker]

Chalk me up as another happy SK7 user. Especially mounted in a bungee mount.

It's been working great for me so far. I've only used it on some 50-odd dives, though, so I don't really know how durable it is.

--
Sent from my Android phone
Typos are a feature, not a bug

 

[redacted]

You mean like I do when night diving? The compass is my reference, like my depth is my reference at night when I ascend. I've had lots of compass practice, decades on land and underwater. Being off 15 20 deg on a 100 yd swim isn't too bad, ya end up pretty close to where ya want. I'm no Navy SEAL after all.

No, I mean try it without even the compass reference. It is a bit surprising how quickly you go off course.