Diver Navigation Board: Sources

[Bryan]

I have been looking for some alternative to a console and wrist-mount compass, and came across one of these... a diver navigation board (apparently used by the military)

From: RJE International, Inc. | Underwater Diving Products - Diver Navigation, Cobra-Tac Navigation & Mapping Consoles, Underwater Compass, Combat Swim Boards, Dive Chronometers, Depth Gauges

In my OW and AOW classes, we're taught to bend your elbow and hold your wrist to keep your compass steady and oriented correctly. If you've ever had to do this for a lengthy swim, you know that gets old quickly. One of these would be far more practical.

The closest thing I could find commercially was one of these:

Results for SCUBA:Combo

But, it really isn't the same thing... does anyone know of a source for one with handles and a marine compass?

I found this site which has an idea for making your own, and I might give it a try:

TacticalDiving.com: content / the tac-board (*)

 

[Tomikp]

The most practical method is using an elastic band instead of a standard band mounted on your compass. Due to this you can simply remove the compass from your wrist, navigate and then give it back. The table you have displayed is, as for me, really crazy stuff.

example here: http://www.dir-cz.cz/images/clanky/vystroj/kompas.jpg

 

[rzep]

RJE products are now restricted for a military sale only: tac boards, tac compass and even this Megasport Italian shallow water depth gouges. This is what I've made for my son navigation exercise using pure O2 closed circuit RB.

rgrds
T

 

[traumadiver]

I was thinking about making my own nav board at one time. The only problem I came up with unresolved was a source for the compass. Sure, I found a ton of compasses that could be used on a boat, but what depth were they rated to? I thought about using a Suunto SK7. Everything else about the construction of the nav board seems easy. Any sources for the compass?

 

[rzep]

Like I said before the original RJE TAC100-2 compass it is no longer sold to public - You can try to get them second hand but it is probably a remote possibility.

or more compact version:

The alternative is Ritchie RU90 used often as a replacement compass for combat swimming applications.

In my board I use Ritchie kayker:

Now as a principal navigation boards are design for a shallow water use, usually with pure O2 rigs limitations - no point for an attack team to rack some serious deco, when they can do a stealth approach at depth of 20 feet.

I don't know how far down You want to take your compass - I have no intentions of taking my board too far. From my experience, I had RJE board bellow 60 feet. As of
that home made board, I've had it at 55' plus, when we practiced switching from OC to CCR.
I have no experience with RU90 bellow 25-30'.
To find the depth limit of those instruments, I think the best course of action would be to contact the manufacturer.
rgrds
Tomek

 

[dkktsunami]

The most practical method is using an elastic band instead of a standard band mounted on your compass. Due to this you can simply remove the compass from your wrist, navigate and then give it back. The table you have displayed is, as for me, really crazy stuff.

example here: http://www.dir-cz.cz/images/clanky/vystroj/kompas.jpg

I do a similar thing - have removed a Suunto compass from a Cobra, stow it in a pocket, hold directly in front of me when in use. This is a light weight, bulk free, interference free method of carrying compass.

 

[muddiver]

Whats wrong with a standaed SCUBA compass? Just remove it from the boot/wrist mount and glue it to your board. Oceanic Swiv Compass Module

You want a depth guage, glue a capalary depth guage to the board. Capillary Depth Gauge

Or you could just buy this: Navigation Slate without Compass

 

[traumadiver]

Muddiver,
I did think about doing that. I just wondered why the special operator NAV boards had the boat style compass. Is it better or something? Any knowledge on that?
THanks

 

[muddiver]

I suspect that there is some Mil Spec that drives the selection that was used to build those. The military does not always specify the most eccinomical or efficient equipment. I would also be leary of the glass dome that a boat style compus would have vs. a good rugged plastic lense. It is possible they think that the large size make for a better to read instrument.

I guess what I am getting at is, unless you know the specifications of the components of what you are going to make, you might buy something expensive that won't work because it was never designed for where you intend to use it. I would think a standard boat compass would eventualy fail when used in a diving environment. They just are not designed for that.

 

[rzep]

I completely agree that for typical recreational navigation, regular scuba compass is all you need.
Nav boards shine when you have to perform precise navigation. Saying that, I don't mean precision in an instrument, but rather precision in process of navigation.
On typical rec dive, we take a glimpse on compass once in while to keep the general direction. Close to the surface we have an option to take a peek and and correct the headings.
Nav boards are made for 'continuous navigation' required for very accurate results. Continuous means you don't put the board down to check the reef or fish. You swim, count kicks:"one - scan area in front of you, two - check our headings, three - check your depth, four- check your teammate, five - check the timer and all over again"
First of all, board gives you opportunity for very stable platform(much more stable than technique of holding your wrist).
Second, it gives you all navigation instrument in sort of cockpit style - easily readable, directly in front of you. In that level of navigation, you check timer and depth gauge as often as compass.
Timer combine with counting the kicks provide you with an estimation of our speed and distance covered. Precise depth gauge, keeps you at the safe depth - to shallow and you can be detected, to deep and specially on O2 rig - 'lights out'.
Finally dome shaped compass vs regular compass gives you not only better readings of our heading but acts also as an artificial horizon - sort of aviation tool telling our trim, pitch and roll - very useful information if you have to swim, let say 2 NM with no reference point (no bottom in sight).
rgrds
Tomek
PS. In terms of depth limit of the compass, I don't think is such a problem - essentially it is a sphere filled with the liquid.
I have more concern of recalibrating my Megasport depth gauge with the maximum range of 60 feet.