Compass advice

[DiveMonkeyDive]

Working on my UW Navigation specialty and I believe my wrist mount compass is is failing to hold a true north bearing. It seems every time I take my bearing then submerge once I reach depth I cannot maintain a "north" bearing to find my objective or my object in my S&R dives. I dont know the brand of compass mine is but its a $35 dollar wrist mount that I bought at Scuba Toys in Dallas. Nothing against Scuba Toys. I dive wth a wrist mount computer so my reg doesn't have an integrated compass. Any advice on one would be great.

 

[Keith.M]

Get a Suunto SK7. They can take 30 degrees of tilt and still be accurate. Yours probably "sticks". I replaced my cheapo Storm compass with it and really like it. I picked up a used one (excellent shape) off of scubaboard with the DSS bungee mount for $55

 

[Jim Lapenta]

Why are you trying to maintain a north bearing? The heading should be the one on which your objective lies. Is the compass being held absolutely level? Are you taking a heading and lining up the index marks with the arrow; compasses are not exact. Are you wearing any object that can interfere with the magnet? Are you starting out with reasonable length legs to swim? I have students begin with legs of no more than four or dive fin kicks. That helps them to also see if they tend to swim straight or have tendency to deviate in one direction. What tasks are you having your buddy do while you work the compass?
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[DiveMonkeyDive]

Get a Suunto SK7. They can take 30 degrees of tilt and still be accurate. Yours probably "sticks". I replaced my cheapo Storm compass with it and really like it. I picked up a used one (excellent shape) off of scubaboard with the DSS bungee mount for $55

Not sure if its sticking or just loses its ability to keep a north bearing. It wobbles back and forth on both sides of north. Leaving me guessing too much.

 

[FinnMom]

Ditto: nothing but an SK7 and nothing but a bungee mount. Both are excellent.
The bungee mount makes it easy to stow the compass higher on your forearm, or remove it from your sleeve to hold in your hand, or secure the compass on the back of your hand. You can navigate with a compass much better if you hold it out in from of you but esp. as a beginner it's also very easy to get distracted and drop it. The bungees are a huge help and hugely less "fiddlely" than a retractor cord.

 

[Instructor_Tom]

compass is one of those things you need on occasion. I toke the wrist strap off mine and rigged it with a bolt snap and line. it stays in my pocket until I need and then it's in my hand. in the hand I find you can level the compass better than on your write and you can hold it below you so you get a better view of the lubber line.

I would suggest try this method before investing more money in a compass.


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[Panama Jones]

I have an absolute ton of above ground orienteering and have now been using dive compasses for a few years. While there are cheap compasses that have very low forgiveness to angle etc, a compass is a very simple instrument more likely to be affected by environmental factors than actual defectiveness. You don't explain the following:

1. Are you absolutly sure your compass is being held as close to level as possible (the cheaper ones get hun up if not level)
2. Are you diving near masses of metal that can affect the direction (even on your person).
3. THE BIG ONE... are you sure it is the compass or is it you? All people who use a compass follow one rule..trust the compass. In darkness or underwater most people want to go where their intuition takes them often thinking the compass has gone off. Take a bearing in something under water (from the surface) that you know is there for sure. Swim to it using the compass only and fight of all intuition that says you off course. Assuming you kinow how to use the compass, it should get you there.

Finally, accept my sincere apologies if I appear to be implying you can't use a compass. I am still one of those dummies and with all my experience it was only last weekend that I took a bearing on a point from the shore and by the time I was down 10 feet I was already thinking I was off course by a few degrees, corrected and missed my target. Did it over again, got the same intuition yet trusted the compass and found my target.

 

[DiveMonkeyDive]

Why are you trying to maintain a north bearing? The heading should be the one on which your objective lies. Is the compass being held absolutely level? Are you taking a heading and lining up the index marks with the arrow; compasses are not exact. Are you wearing any object that can interfere with the magnet? Are you starting out with reasonable length legs to swim? I have students begin with legs of no more than four or dive fin kicks. That helps them to also see if they tend to swim straight or have tendency to deviate in one direction. What tasks are you having your buddy do while you work the compass?
Sent from my DROID X2 using Tapatalk

Sorry for the confusion. My last dive was at the lake and I use the north bearing to get my directional bearing. I then set my north arrow to the single arrow on the compass face to my degree that I need to travel according to north to swim the legs of the desired pattern for Nav and S&R. Im gonna have to check on the leg kicks affecting my direction when I swim. The only tasks I've worked on are triangle and square navigation patterns and directional swimming to objects, in these cases either platforms of boats. Im usually multi-tasking the computer and the compass.

---------- Post added June 5th, 2013 at 12:35 PM ----------

I have an absolute ton of above ground orienteering and have now been using dive compasses for a few years. While there are cheap compasses that have very low forgiveness to angle etc, a compass is a very simple instrument more likely to be affected by environmental factors than actual defectiveness. You don't explain the following:

1. Are you absolutly sure your compass is being held as close to level as possible (the cheaper ones get hun up if not level)
2. Are you diving near masses of metal that can affect the direction (even on your person).
3. THE BIG ONE... are you sure it is the compass or is it you? All people who use a compass follow one rule..trust the compass. In darkness or underwater most people want to go where their intuition takes them often thinking the compass has gone off. Take a bearing in something under water (from the surface) that you know is there for sure. Swim to it using the compass only and fight of all intuition that says you off course. Assuming you kinow how to use the compass, it should get you there.

Finally, accept my sincere apologies if I appear to be implying you can't use a compass. I am still one of those dummies and with all my experience it was only last weekend that I took a bearing on a point from the shore and by the time I was down 10 feet I was already thinking I was off course by a few degrees, corrected and missed my target. Did it over again, got the same intuition yet trusted the compass and found my target.

You make a couple good points. I am sure I am holding the compass as level as possible, but there s always that possibility that it could be off while strapped to my arm. I do know for a fact that we dive near metal, steel training platforms and the huge steel shark. So I see how that can affect its performance. Although I made a couple dives just to ensure that it was the equipment and not the surroundings OR operator error. The latter being the one I had to make extra effort to ensure it wasn't.

Btw, no offense taken in your post. I got a BIG laugh out of it. Sounds like we have the same luck,

 

[00wabbit]

I bought a cheap compass at my shop and it stuck if you were even slightly off level which is hard to tell underwater. One guy had one that would rotate to point north in which ever direction you pointed it, it was very odd.

Agreed on the SK7 everyone uses is and it is very forgiving on the angle you hold it.

 

[Jim Lapenta]

One big reason I wrote an Underwater Navigation Course for SEI was because the old one left over from the YMCA program sucked. As IMO do many others if you go by the book. There is not nearly enough emphasis on the importance of sharing the task loading between the buddies in any of the other course material I see. For those new to Nav underwater I cannot emphasize enough how important it is to share the load. There is so much going on with successful navigation that it takes hard work, serious time, and lots of dives for most people to get to the point where they can do it all. It took me over 50 dives and pages of detailed notes, creating maps, doing the up periscope look see to verify, and more focus than most of the buddies I had wanted to devote to it. I am pretty good now with all phases. Compass, Natural, and the use of lines and reels. Fortunately I had a mentor that told me to take the stuff in my Nav class and throw it away for now at the time. The course was set up to create confusion, unrealistic expectations, and totally ridiculous exercises that damn near guaranteed frustration and disappointment. Especially under our local conditions.

So I took all of those lessons and wrote my own that uses double the number of dives, 6-8 hours classroom, and introduces lines and reels as a useful tool. And starts out in small steps that result in divers rapidly gaining confidence and knowledge.

And the absolute most important part is that divers need to share the load and communicate effectively. If they don't it can be a biatch to catch on to.