Underwater Navigation How To Use A SCUBA Compass

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The most commonly used SCUBA navigation device is the compass. All divers have one and should carry it with them whenever they descend into the abyss. We all know that there is no such thing as an underwater GPS for Divers! Unfortunately, many of us, including myself when I first started, do not really know how to correctly use the compass to navigate underwater.

The parts of the compass:
The Card:
This is the part of the compass that has the degrees and the letters that determine direction
The Bessel:
This a rotating piece of plastic on the outside of the compass which can be rotated to help us read our heading
The Lubber Line:
This line is fixed on the compass' face and is used to help us read our heading.
The Side Window:
This is a window on the side of the compass that makes it easier for us to see our heading.
**Note that a digital compass does not have all these parts**

How to Use a Compass for Underwater Navigation
The first thing we need to go over is how to hold your compass when underwater. This is important because different compasses are mounted in different ways. Not knowing how to hold a compass can cause you to get an incorrect heading
Taking a heading
A heading is the number attached to the direction you are traveling in. It will always fall between 0 and 360 and is commonly known as degrees.
The Reciprocal course
This is a very common question. Because we take headings in a circle from 0 to 360 degrees, it is possible to calculate your reciprocal, or opposite heading. To do this we use something called the add subtract 180 rule. It requires a little math, but it is not difficult.
How to use your compass to assist in natural navigation.
It is a great idea to use your compass in conjunction with natural navigation. This is a very good way of avoiding tunnel vision, something that occurs when you are laser focused on your compass and you do not notice what is happening around you. I have seen it happen more than once that a student will focus so singularly on their compass that they will swim right passed the ascent line without even noticing it.
What if there is a cross current?
There are times when you will be swimming with a current coming across your body rather than in front or behind you. The idea here is to slightly deviate your swimming by slightly directing yourself into the current to compensate. Of course, this is not an exact science, but it will allow you to compensate for the current and get you closer to your destination.
I hope this has helped you understand the ins and outs of using a compass as a SCUBA navigation device. If you want to learn more all aspects of underwater navigation, you may be interested in b our course "SCUBA navigation mastered." It provides a comprehensive course on all aspects of navigation. Click the link or the button below.

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In it, we go over several often-overlooked tools that you can use to navigate. Many of these tools are not reviewed by instructors so you definitely want to check it out.

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Thanks for watching

[worldgirl]

No mention of setting the bezel and aligning it with the North, or how to use the ticks on the dial to see adjust your heading or see if you are deviating from your course.

[marksargent]

I seem to recall something about rotating the bezel, and then keeping North/South in line, so you just have to make sure they line up, rather than remembering the actual number?

[tinapye]

I am a complete newbie to compass navigation. Did I miss something? Did this man mention anything about the North Needle to then set your bearing? I am Googling many sites to try and understand how to use a compass under water. BOY this man talks fast. Very informative, but missing the crucial explanation of the North needle to set up your bearing (unless I missed it in his very quick chat?) and could talk slightly slower for me to grasp what he is explaining.

[illusionclassicrock]

Wish you would’ve covered changing direction underwater. For instance if you have to swim to a certain mark underwater, and then turn and swim to another point.

[UWfalcin]

Lol what?! You didn't even show how to operate the needle?

[carlossantos]

At last an explanation that most newbies will understand, simple and straight to the point, of course there's more to it but great for people who know nothing about underwater navigation 👍

[jerardwashington]

Thank you buddy for the brief breakdown

[ChattingwithMarkStise]

A really great video, thanks for posting.

[WillM-lkwd]

Do you have an updated video that shows when you're making turns underwater and what to do with your compass?

[richardmooney]

Great job! Love advice to incorporate observational way points and to look "over" the compass using the window or the lubber line. Excellent! Couple additional points:

1. It is critical to recognize that these compasses are not that accurate no matter what you do, and are going to be off by 10% or more the further away the objective so set the target goal a little to the left so you know you need to search right when you get to the location (best done using a weight and spool to circle accurately to the right);

2. You must, must, must estimate distance so you have some reasonable idea where to make the adjustment to begin turning right to search for your objective. Otherwise you have no idea where you are! Best option is to use kick cycles but you can use breaths or time but I find these too subject to being influenced by effort on a long swim. Bottom line: You need both direction via the compass AND distance to hit your mark.

Finally when you use the "arm crook" position or figure 4 position place your middle finger in the elbow notch to ensure the crooked arm is at a 90 degree angle. I like bungee mount on the back of my right hand, but that is just a personal preference.

Good Luck!

[rob_]

Other than going to the surface to sight the boat, is there a way to pinpoint a boat's anchored location when you leave it, and then navigate back to it using a compass? Other than swimming a straight line out and back again (or swimming a square and counting kick pairs)? It seems easy to swim around looking at things and then realize you have no clue where the boat is.

[searcher]

Hey thanks for the information. Great review. Been out of the water for a while and itching to get back in this spring.

[WASF]

And please describe or ADD another video on how to set a bearing to the destination and returning from the destination.

[c.patricksadowski]

what is the make/model of the compass you are using?

[suesaines]

Very well explained . Thank you from a learner diver

[wendyblevins]

This a very concise video with nice reminder info for my OW students. Thanks so much! :)

[Yggdrasil]

What is the rotating ring on a compass used for?

[scottmaskal]

Worst explanation ever, didn’t mention the rotating bezel, the relation of the index marks to the north needle.

[glennmiller]

Insupportable sa voix on comprend rien tellement il est rapide et bien si il est stressé autant qu il parle doit pas rester beaucoup d'air dans le bloc en fin de plongée...