Compass issues

[lowviz]

I couldn't possibly agree more. I often attempt and assess no viz "where I think I'm going" navs. No way. Forget it.

I need at least one solid reference. Sometimes it is just running a line out without slack, but it has to be something physical...

 

[Bob DBF]

I had a compass like the OP's and it went bad. It was quite frustrating because it worked perfectly at times, so when it did not get back to North it wasn't expected, and unfortunately, was when I was deep and dark and needed it the most. My buddy just thought it was me until the day we surfaced from a deep dive and he was going to show me the right way to use it. The card hung up somehow and held directions other than North, after which I ordered an SK7 which seems to work just fine. The only theory we could come up with is that, for whatever reason, the depth and cold changed the properties of the oil so the card could not swing freely. It will still work fine in 30' of water, even if it is cold.

A problem I ran across, when using a compass, is to wait for the card to settle out before starting on the course. The more time you take making sure you get an accurate reading, the more accurate your course will be. I also believe in a compass board which gives you a longer lubber line to follow, and I use the slate for any notes I might need later. My preference is a retractor on the board so I can put the unit in front and below me for a better course line and when I drop it to tend to other issues it gets the he** out of my way.



Bob
-----------------------------------------
You only need two tools in life – WD40 and Duct Tape. If it doesn’t move and should, use the WD40. If it shouldn’t move and does, use the Duct Tape.

 

[Storker]

It is a bit surprising how quickly you go off course.

Heh. I've lost count of the number of times I've been picking scallops¹ and after stuffing a couple of shells in my catch bag thinking 'OK, we were coming from there, so it's that way'. Then I check my compass and find that I'm more than 90 degrees off course... :blush:


¹ Around here, we usually pick king scallops, and the perfect site has a flat or very slightly sloping sandy bottom close to a steeper fall towards deep water. That's not a type of terrain that's particularly easy to navigate "naturally".

 

[bc214]

Trident stuff is, in general, crap. As you're seeing, you don't get enough play on tilting it without screwing it up. Also, however, could be an issue with how you're holding it. Holding a slate-mounted compass by the near end of the slate other than perfectly aligned with your midline and direction of swim will multiply any error you're encountering.

How are you holding it? The best way is cupping the compass itself in BOTH hands out in front of you; this will essentially force you to keep the compass aligned with your body... unless one of your arms is longer than the other. Can you pop the compass out of the slate and try it that way?

My students have good experiences with Suunto SK7 or the Oceanic SWIV compasses - both of these are very forgiving in terms of tilting without getting hung. I use an Oceanic personally; the SWIV's predecessor.

Where in NJ are you located? You're welcome to borrow one from me to try out if you like.

Thanks man. I am from North Jersey, right near the Willowbrook Mall in Wayne. I actually picked up the Oceanic SWIV and it is miles ahead of that other piece of junk. I can now effectively land navigate with it, and it is much closer (although still not quite as capable) as my lensatic. I appreciate the offer, but I am all set for now. I'm trying to get in the water before my RI ocean dives, so hopefully I get a chance to try it out.

---------- Post added October 6th, 2014 at 09:17 PM ----------

I've never done this but it looks good on paper. Get 2 line levels. These are small one bubble levels masons use to hang on a string to give themselves a level reference. Attach them to that slate 90degs from each other so that pitch or yaw you'll see one of them change. Use them to get a feel for keeping the compass level. Sounds good huh? Finding a way to keep them on while diving would be ideal.

There are no large amounts of iron in RI and a compass is basic gear especially at night when even at the surface direction is tough to determine.

You'll want to be able to use a compass to enjoy diving here in RI. I have used my compass to find my way back to a steel hull ship in NC but you need to watch it to know when it starts moving off the earth magnetic field and onto the ship. Contact me when you get certified we'll do some diving when you're in RI.

Thanks man. I'm just working on my AOW right now; I have my OW. I'll be up there the weekend of the 17th-19th, but if I can swing it, I might try to come up a day early and/or stay a day late to do some more diving. We shall see how the work/school schedule goes.

---------- Post added October 6th, 2014 at 09:19 PM ----------

View attachment 194355

build one of these, piece of plexiglass from home depot, sand it down so you can write on it. Drill a hole in one corner, and zip tie a bolt snap to it. drill two small holes at the top and put a small piece of bungee on the top to hold a pencil. Superglue a $10 wally world compass to the bottom left corner and voila, cheap very easy to use compass, much better than the floating crap compasses that are barely good enough for cardinal ish directions. I have used the slate in this picture to do a 500yd blue water kick *40ft depth quarry with 15ft of vis and was diving at 10ft depth the whole way* was accurate within 5ft by the time I got to the other end, hit the buoy I was aiming for. It will deviate somewhat when you are close to heavy metallic objects, but you have to be decently close when you're underwater.

Thanks. That thing is really cool. What sold me was the slate/compass combo, which gave me the option to keep data very handy, and write up whatever I needed underwater. I really like your board, and I will be making up one of these for sure.

---------- Post added October 6th, 2014 at 09:20 PM ----------

View attachment 194356

If you can find one of these in good shape on Ebay, buy it. It is probably the best and most forgiving compass ever made. Someone at Scubapro that probably didn't know crap about diving or compasses decided to stop making them. I use one mounted on a console. In 44 years of diving I'm on my second one, they last too! It is a Scubapro LS-1 compass.

My instructor told me the exact same thing. I trolled around for a while and couldn't find a single one. Apparently they are THE compass, and if anyone has one, they are not likely to part with it.

---------- Post added October 6th, 2014 at 09:22 PM ----------

Most problems using a compass originate in the user staring at it while swimming. Just point your compass to a point as far away as possible and swim to it. Repeat. It's that easy.
If you stare at your compass, you will veer off in one direction.

What you are saying compares quite nicely to land nav, which I am pretty familiar. Basically, you just go from point to point which is pretty easy. Where I am diving, visibility may be 6-10 feet sometimes, and that style of nav just won't work. Unfortunately, in certain conditions, following the compass and swimming along are the only ways to go.

---------- Post added October 6th, 2014 at 09:27 PM ----------

Lastly, I picked up the Oceanic SWIV, as it came recommended by members here as well as a few others. It is substantially taller than my trident, and although it is not mounted on a board, it easily could be. I have a small slate, and after my AOW dive, I was thinking about stealing the retractor from the POS compass board and mounting it to my small slate, and then adding either my SWIV or a new/different compass to create something as depicted above.

As far as the comparison goes, I'm almost ashamed of myself for not noticing before my AOW quarry dives. The Oceanic SWIV is wolds ahead. If I take a heading with it, then tip it in any of the four primary directions up to 20 or even 30 degrees, it is still WELL inside a usable margin of error. The Trident heading will skew up to 30 degrees off course.

Thank you all for the tips, and I am looking forward to putting a functional compass to work within the next few weeks.

-BC

PS: Please forgive any spelling or grammatical errors, I have been responding entirely from my ipad and keyboard...

 

[cascas]

What you are saying compares quite nicely to land nav, which I am pretty familiar. Basically, you just go from point to point which is pretty easy. Where I am diving, visibility may be 6-10 feet sometimes, and that style of nav just won't work. Unfortunately, in certain conditions, following the compass and swimming along are the only ways to go.

If 6-10 feet is your max Vis, you will have to adapt the frequency of checking for a new point.
Best option is to get your general direction from your compass and find 2 or preferably 3 objects that are as much in line of the direction you are going, constantly looking for more objects further away. These objects can be as small as just details in the bottom. Every now and then verify your compass for direction.
Bottom line is that you need to look where you want to go to get there. Closing your eyes or staring at a compass will make you swim circles.
I regularly dive in Vis that low. Been doing it for 17 years.

 

[bc214]

If 6-10 feet is your max Vis, you will have to adapt the frequency of checking for a new point.
Best option is to get your general direction from your compass and find 2 or preferably 3 objects that are as much in line of the direction you are going, constantly looking for more objects further away. These objects can be as small as just details in the bottom. Every now and then verify your compass for direction.
Bottom line is that you need to look where you want to go to get there. Closing your eyes or staring at a compass will make you swim circles.
I regularly dive in Vis that low. Been doing it for 17 years.

Any tips on blind navigation? What about when you are at a depth that has nothing to reference? For example, while in 50' of water and mounting a depth of 25' and attempting to navigate?


Sent from my iPhone using Tapatalk

 

[tbone1004]

ideally you are not doing this solo. Assuming you have a buddy, here's how

you have to do a modified breast stroke kick, flutter kicking isn't very good for navigating

Diver on the left has control of depth and is responsible for looking around to make sure you don't run into stuff. Left hand is on inflator and he is monitoring depth. Right hand is holding onto left tricep of lead diver. Don't hold on too tight, just enough for touch contact. You have control of his depth this way by indicating up and down as needed.

Diver on the right has the slate that I pictured in his right hand holding the bolt snap. Left hand is on inflator. By holding the bolt snap with the right hand and having the compass on the left it is easiest to bisect the body to get accurate navigation.

Divers have to kick at relatively the same time and this can be controlled by the diver on the left who is in touch contact. Diver 1 looks at the waypoint, aligns the dive team, and kicks. After the kick raise your head, look around and make sure you aren't where you're supposed to be if you know you are close. Look back down, make sure you are still aligned, and kick.

Diver 2 has to make sure he is truly parallel to diver 1 so he isn't pushing the team to the right which is the most common problem. If one diver is significantly stronger than the other you can yaw a little bit to the left or the right.

If you're doing this solo, same principle applies but after each kick you have to verify depth and direction. Computer/depth gauge on the right wrist works, if using a console you can drape this over your arm.

Here's a video on how to assemble the slate

[video=youtube_share;x0z4T_3KjFM]http://youtu.be/x0z4T_3KjFM[/video]

 

[cascas]

Any tips on blind navigation? What about when you are at a depth that has nothing to reference? For example, while in 50' of water and mounting a depth of 25' and attempting to navigate?


Sent from my iPhone using Tapatalk

If its sunny, you can use the direction of the light penetrating the water to guide you. Only when there is absolutely no visual reference, keeping the compass within eye shot is useful. Just do not expect spot on navigation. But let's be honest, how often is that a real issue ?

 

[lowviz]

...//... Just do not expect spot on navigation. But let's be honest, how often is that a real issue ?

Yes!

At the end of the day/night I just wanna go home...

 

[mrdre]

Any tips on blind navigation? What about when you are at a depth that has nothing to reference? For example, while in 50' of water and mounting a depth of 25' and attempting to navigate?


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You just keep watching the compass and the depth gauge constantly. Without any visual reference that's the only way. Our senses of "direction" don't work under water. For example if I have any visual reference then I (obviously) can go straight where I need to. If I don't have any visual reference then I always turn left and after 7-8 kicks I end up going -90 degrees. My right leg kicks more efficiently because I'm righty. I guess if there is some visual reference, then the brain adjusts the strength of the kicks. If there is no reference then the brain gives free will to the legs, but keeps convincing itself that I'm going straight. If I think about adjusting the strength of my left kick then I keep turning right. Maybe eventually with a lot practice I can swim straight, but then there are currents that may change your direction, so it's pretty much pointless skill. The only reasonable way is just to watch the compass every couple of kicks.