Compass - any one use it yet?

[James R]

Does one have to calibrate the compass on the Petrel before each dive?

No, just an initial calibration that takes very little time.

 

[Scared Silly]

The other error is more subtle...at best, the compass points toward magnetic north, which is not the same as true north; the difference is called magnetic deviation.

I have always known it as magnetic declination. It is not really an error per say but a geophysical phenomena that one must account for when using a compass:

Magnetic Declination (Variation) Home

 

[tursiops]

I have always known it as magnetic declination. It is not really an error per say but a geophysical phenomena that one must account for when using a compass:

Magnetic Declination (Variation) Home

Yes, you are correct, I was being sloppy. Declination is exactly the problem of true vs magnetic heading. Deviation is the problem of local fields causing an additional error; unfortunately, like DCS and SAC being used to mean different things by different people, deviation is sloppily used to mean both declination and the local/deviation problem. My bad.

 

[guyharrisonphoto]

Does the compass offer a reciprocal bearing function, for swimming a return course?

 

[decompression]

Yes, once the initial course mark is set (green color) the back bearing/recip is in red.


Sent from my iPhone using Tapatalk

 

[Scared Silly]

Thanks to some very good luck the wife has a shinny new Petral 2 in her hands and no need of an analog compass .

 

[BFRedrocks]

FWIW, I took my new Petrel 2 out for a few dives last week and found the compass to be very useful (and much, much better than certain digital compasses I've used before). I had it set to show 90 degrees, which I noticed really quickly made it hard to hold a specific bearing because the degrees changed too quickly. I've since switched to the (I think) default setting of showing 60 degrees, which is less sensitive to small changes in orientation.

The only other thing that I would consider a slight "negative" in my opinion is that the setting to mark a bearing is a few button presses down and requires you to essentially exit out of the compass to do it. So when you are marking a bearing, you're not able to see the actual compass while you're doing it. Maybe I'm wrong, or maybe that is fine for most divers looking for a general direction, but I didn't see a good way to mark a bearing at say 256 degrees unless I oriented the compass in that direction and held it perfectly still while I switched to the mark compass setting.

If that is correct, maybe there's a way with an update to the firmware that if the compass is showing, one push of the left button marks a bearing, rather than having to do 2 or 3 pushes. All in all though, it's a great compass.

 

[oldschoolto]

Give me a plain old compass.... Still have them as the go to in all aircraft.... This is the cockpit of a boeing 777... Right in the middle is the plain old compass to get them home....

Jim...

 

[oldschoolto]

I guess no one likes the fact that in a 2015, state of the art $320 million dollar airplane... They still put a good old fluid filled compass to get them home..

Jim...

 

[gopbroek]

Actually they put it there because the US law still requires it. The same holds true for requiring an ashtray in the lavatory and that the flight attendants show you how to use that new- fangaled device called a 'seat belt'.