Dive Like a Pro/ Tips from Tom
The North and South or East and West of using a compass!!
Most diver's I know get a little foggy when you ask them about compass use.Why bother they ask when you just jump in the water off the dive boat and the DM points you in the right direction!?
And my usual response to them is " What if the DM buggers off or has an AGE, then where are you??!".
They usually reply with a "POINT TAKEN"!
In some point or at a certain time you're going to say to yourself, "I'm tired of playing follow the leader, maybe my buddy and me should go it alone!!".
This is where your compass comes into play and you SHOULD KNOW HOW TO USE IT!!
Your compass is an invaluable little tool and you should know how to use it! It gets you to Point A and then back again,(a reciprocal course).
It's great for navigating a multi-route course around a dive site, where multiple leg-routes are involved, and at the end of the dive to confirm where your exit point is and swim towards it!
UNDER WATER!!
Compasses come in different styles with the most common being into your gauge console, along with your depth gauge, and psi gauge.
Another form is a wrist compass which is on straps like a watch. I use one of these as a back up to my primary compass in my console.
BASIC COMPONENTS:
A dive compass has 4 components that every diver should know and how to use them:
1) The Lubber Line
2) The North Arrow
3) A Rotating Bezel with reference marks (looks like a watch dial)
4) Degree Calibration Marks
FIRST OFF IS THE LUBBER LINE:
The lubber line is what marks the direction that the diver is going in. The compass is always held so that the lubber line is perpendicular (sp?) to the diver's shoulders and parallel to your line of site. My spelling isn't the greatest so please bear with me.
THE MOST BASIC COMPONENT OF THE COMPASS:
THE NORTH ARROW:
The North arrow on every compass always points to the Magnetic North. If you move the compass clockwise or counterclockwise (backwards) the arrow will always point to the Mag. North!!
But it changes position's with in the compass case. Regardless of how many tricks you try on your compass the arrow is always going to be NORTH!!
THE COMPASS IS EQUIPPED WITH A ROTATING BEZEL:
The bezel contains 2 reference marks on it, the primary mark ( 0 degrees) and the reciprocal mark (180 degrees) N and S .
These 2 primary marks give the diver a reference when travelling out to a point ina straight line, and the reciprocal mark brings you back to the starting point, ( The gate for you horse racing fans).
THE DEGREE CALIBRATION MARKS
Dive compasses also have the degree calibration marks and these marks run from 0 (zero) degrees to 360 degrees. You use these marks when doing a multi-leg underwater route or when going from one known point to another.
The degree markings are similar in all brands of dive compasses, but, some calibration marks are displayed in different ways. Some compasses have the marks on the outer face only, some have them on the outer and inner face, and some even have them on a really convenient side window for seeing them from the side.
PRETTY SIMPLE TO USE:
No matter what kind of course you're diving the compass is always held out in front of your body and slightly below eye level. The lubber line is then positioned perpendicular to your shoulders and pointed STRAIGHT ahead in the direction that you want to go.
But to function properly it has to be on a level plain.
This is where I use my right hand and arm pointed straight out, and bring my left hand around and rest it on my right arm, with either the wrist compass or the console compass.
NAVIGATING USING A COMPASS:
To do this you must first establish a compass course. To do this you point the lubber line,(the straight line inside your compass) in the direction you want to go.
Then you rotate your bezel until the primary reference marks are directly over the N arrow. You usually establish your course from just before entering the water from a dive boat, or from the beach if you're doing a shore dive.
Or you can even do it from a boat's anchor line after you've descended.
To keep the course underwater you simply swim forward, (remembering to breathe as this isn't stressful),
keeping the N arrow between the 2 reference points. If you go off course the arrow will move to one side or the other of the reference points.
To correct this and get back on track so to speak you just swim left or right until the N arrow is once again between the 2 reference marks. As long as the arrow is between the marks YOU'RE ON COURSE!!
Easy huh??
To get back to the starting point just reverse your course, slowly turn your body until the N arrow is situated directly in line with the reciprocal reference mark and follow it back. VOILA!!
You're at the post and the other horse's that can't use compasses are out of this race!!
OTHER CONSIDERATIONS WHEN USING A COMPASS:
You'll quickly learn that other things affect your compass use, CURRENT, is one of them, a strong cross current makes it difficult to keep on a straight compass course.
Even if you keep the N arrow where it should be you may find yourself drifting off your intended course due to the current pushing you sideways.
Always be aware of this and compensate to make up for this current
Large iron ore deposits will affect compass correctness as will other metals. I'm sure our diving friend's in Northern Minnesota around Virginia, Orr, Lake Superior, Bemidji, can attest to this.
I was doing a quarry dive near Orr MN once and got completely confubled because I forgot I was in the Iron Range mining belt!
It buggered me up by 9 degrees! That's why pilot's have TRUE NORTH and MAGNETIC NORTH headings, and I've been flying 23 years, I should have known better!!
And you know that something as simple as having a dive knife near your compass under water can affect it!! It can!!
But sometimes it is neccessary to depend totally on compass navigations, but if you have the chance combine your compass navigation with your natural navigation techniques.
Use UW reference points, visable down lines, coral or rock formations that you recognize. It all helps.
But lastly I have to say that if you're still not 100% comfortable with using your compass, take a nav specialty course from your local instructor!!
You'll be amazed at the pearls of knowledge you'll get from them!!
DIVE SAFE EVERYBODY!!
Thomas D. Hanaway
MSDT PSD Level 4
IANTD SSI NAUI PADI
SDI/TDI/ERDI PSAI PSDA
IADRS
DCBC (Diver Cert. Board of Canada)SSA Diver/Tender
The North and South or East and West of using a compass!!
Most diver's I know get a little foggy when you ask them about compass use.Why bother they ask when you just jump in the water off the dive boat and the DM points you in the right direction!?
And my usual response to them is " What if the DM buggers off or has an AGE, then where are you??!".
They usually reply with a "POINT TAKEN"!
In some point or at a certain time you're going to say to yourself, "I'm tired of playing follow the leader, maybe my buddy and me should go it alone!!".
This is where your compass comes into play and you SHOULD KNOW HOW TO USE IT!!
Your compass is an invaluable little tool and you should know how to use it! It gets you to Point A and then back again,(a reciprocal course).
It's great for navigating a multi-route course around a dive site, where multiple leg-routes are involved, and at the end of the dive to confirm where your exit point is and swim towards it!
UNDER WATER!!
Compasses come in different styles with the most common being into your gauge console, along with your depth gauge, and psi gauge.
Another form is a wrist compass which is on straps like a watch. I use one of these as a back up to my primary compass in my console.
BASIC COMPONENTS:
A dive compass has 4 components that every diver should know and how to use them:
1) The Lubber Line
2) The North Arrow
3) A Rotating Bezel with reference marks (looks like a watch dial)
4) Degree Calibration Marks
FIRST OFF IS THE LUBBER LINE:
The lubber line is what marks the direction that the diver is going in. The compass is always held so that the lubber line is perpendicular (sp?) to the diver's shoulders and parallel to your line of site. My spelling isn't the greatest so please bear with me.
THE MOST BASIC COMPONENT OF THE COMPASS:
THE NORTH ARROW:
The North arrow on every compass always points to the Magnetic North. If you move the compass clockwise or counterclockwise (backwards) the arrow will always point to the Mag. North!!
But it changes position's with in the compass case. Regardless of how many tricks you try on your compass the arrow is always going to be NORTH!!
THE COMPASS IS EQUIPPED WITH A ROTATING BEZEL:
The bezel contains 2 reference marks on it, the primary mark ( 0 degrees) and the reciprocal mark (180 degrees) N and S .
These 2 primary marks give the diver a reference when travelling out to a point ina straight line, and the reciprocal mark brings you back to the starting point, ( The gate for you horse racing fans).
THE DEGREE CALIBRATION MARKS
Dive compasses also have the degree calibration marks and these marks run from 0 (zero) degrees to 360 degrees. You use these marks when doing a multi-leg underwater route or when going from one known point to another.
The degree markings are similar in all brands of dive compasses, but, some calibration marks are displayed in different ways. Some compasses have the marks on the outer face only, some have them on the outer and inner face, and some even have them on a really convenient side window for seeing them from the side.
PRETTY SIMPLE TO USE:
No matter what kind of course you're diving the compass is always held out in front of your body and slightly below eye level. The lubber line is then positioned perpendicular to your shoulders and pointed STRAIGHT ahead in the direction that you want to go.
But to function properly it has to be on a level plain.
This is where I use my right hand and arm pointed straight out, and bring my left hand around and rest it on my right arm, with either the wrist compass or the console compass.
NAVIGATING USING A COMPASS:
To do this you must first establish a compass course. To do this you point the lubber line,(the straight line inside your compass) in the direction you want to go.
Then you rotate your bezel until the primary reference marks are directly over the N arrow. You usually establish your course from just before entering the water from a dive boat, or from the beach if you're doing a shore dive.
Or you can even do it from a boat's anchor line after you've descended.
To keep the course underwater you simply swim forward, (remembering to breathe as this isn't stressful),
keeping the N arrow between the 2 reference points. If you go off course the arrow will move to one side or the other of the reference points.
To correct this and get back on track so to speak you just swim left or right until the N arrow is once again between the 2 reference marks. As long as the arrow is between the marks YOU'RE ON COURSE!!
Easy huh??
To get back to the starting point just reverse your course, slowly turn your body until the N arrow is situated directly in line with the reciprocal reference mark and follow it back. VOILA!!
You're at the post and the other horse's that can't use compasses are out of this race!!
OTHER CONSIDERATIONS WHEN USING A COMPASS:
You'll quickly learn that other things affect your compass use, CURRENT, is one of them, a strong cross current makes it difficult to keep on a straight compass course.
Even if you keep the N arrow where it should be you may find yourself drifting off your intended course due to the current pushing you sideways.
Always be aware of this and compensate to make up for this current
Large iron ore deposits will affect compass correctness as will other metals. I'm sure our diving friend's in Northern Minnesota around Virginia, Orr, Lake Superior, Bemidji, can attest to this.
I was doing a quarry dive near Orr MN once and got completely confubled because I forgot I was in the Iron Range mining belt!
It buggered me up by 9 degrees! That's why pilot's have TRUE NORTH and MAGNETIC NORTH headings, and I've been flying 23 years, I should have known better!!
And you know that something as simple as having a dive knife near your compass under water can affect it!! It can!!
But sometimes it is neccessary to depend totally on compass navigations, but if you have the chance combine your compass navigation with your natural navigation techniques.
Use UW reference points, visable down lines, coral or rock formations that you recognize. It all helps.
But lastly I have to say that if you're still not 100% comfortable with using your compass, take a nav specialty course from your local instructor!!
You'll be amazed at the pearls of knowledge you'll get from them!!
DIVE SAFE EVERYBODY!!
Thomas D. Hanaway
MSDT PSD Level 4
IANTD SSI NAUI PADI
SDI/TDI/ERDI PSAI PSDA
IADRS
DCBC (Diver Cert. Board of Canada)SSA Diver/Tender