Compass navigation question

[Jasoncassanova]

I've been watching this video from youtube about underwater navigation with the use of a compass, I just have a question that someone here might be able to explain.

I the middle part of the video where the guy mad an example of using an imaginary line between the two reef areas and lined it up with the lubber line, in this case he placed the zero on the north which was on a 45 degree angle on his right side. so from the reefs he went out to the blue and went around following barracuda's and when he was about to go back to the reef he would just move around his body until the north would be back in zero degrees. my question is that the line is parallel to the two reefs so the position of the north is side ways, it would be really hard to swim back in that position. so going back to the reef area, how do you navigate yourself using the compass?

i had an idea that i would just point the lubber line to the 180 degrees since it was on the direction going back to the reefs, but maybe i am wrong...

YouTube - Compass use - the most applicable

 

[Jasoncassanova]

YouTube - Compass use - the most applicable

 

[TSandM]

I agree -- that example is confusing.

He's setting the lubber line to show the line from one reef to another. At this point, being a bear of very little navigation brain, I would look at what that heading was (say, for simplicity, it's due East, or 90 degrees). Now I swim away from that line to the left of it, or to the north; when it's time to return to the line between the reefs, I would swim south.

If you have north caged between either the double marks or with the single mark, and you swim in the direction of the lubber line, you are swimming parallel to the line between the reefs, which won't get you back. I don't think he made the strategy here very clear.

 

[AfterDark]

I agree he made it a little too detailed. The lubber line in his example was just to orientate himself to the east / west direction of the reefs. Clearly the shortest way back to the reef area is due south. Southwest would get him back to the area he left. Southeast would take him approximately where he would have been had he not detoured to chased barracuda, more or less. The part about the lubber line could have been left out and a simple 180 degree change of direction would have been easier to understand.

 

[OneRestlessNative]

His examples are not the way I was taught to use a compass or to navigate by one. It does however show that the compass can be utilized in different methods for effective navigation and orientation.

He was just using the bezel to mark the location, to regain, and get the original bearing or orientation. For the reciprocal or return it would be 180 degrees (north would now be south) or a pre-determined heading to the next location based on the original heading and direction of travel.

It took me a second to see where he was going with it, but I can see his logic and concept behind it.

 

[Teamcasa]

I thought it was a very clear and simple way for new divers to use a compass for general, get me to point x navigation.

 

[Hatul]

His way of using the compass is they way I use it. Rather than locking the lubber line on a direction and fiddling with it, he uses it to orient himself in the dive site.

So he knows the direction between the two reefs and if he swims say perpendicular say 270 from that line he has to come back on reciprocal course to return, but once a mental image is set you don't need to fiddle with the compass lubber line again.

Adam

 

[Bob DBF]

It is very usefull when hunting or "follow your nose" diving, my favorites, where you are not going to navigate to a paticular object or log the course to retrace it to return. In addition, should you get disoriented during the dive a compass check gives the direction from the boat to shore and you can use your best guess how far off the line you are.

By also noting the depth the boat is anchored and any landmarks on your way out you can find the boat or get pretty close for a short surface swim back.

I perfer this method to spending my dive navigating, unless I'm training or trying to find a specific object.


Bob
-------------------------
"If it ain't broke,don't fix it!"