Integrated depth gauge the next snorkel?

[Chavodel8en]

I have a depth gauge in my console, along w my SPG -- I started diving with just it & a watch, and Ive maintained them after I bought a (wrist) computer.

If my computer fails, I don't want to end my dive. So the redundancy is welcome in that way. I have had computer fails mid-dive. I was on a familiar shallow shore dive. I continued my dive.

If my depth gauge dies? Probably wouldn't replace.

 

[John C. Ratliff]

As a contingency it is widely known and taught that if you don't have any way to gauge depth, to ascend no faster than your smallest bubbles. You'll have to go back and read my post as I think you didn't comprehend it. I specifically said optional. But my point was doing a safety stop without a depth gauge is elementary, assuming you can see the surface.

I sometimes dive in enough current that my bubbles travel horizontally, and don't head for the surface for a while.

SeaRat

 

[John C. Ratliff]

WOW! It is the great idea, to add selfmade depthgauge to the Schnorchel !
It is very simple to made it, mark it, and use when you loss you computer, buddy, bouy (with marked line), and head

V (current) = V (max.) * 10 / (10 + depth) is the metric formula for marking depths
You just have to add transparent tube (even soft is suitable), mark depthes, and be happy!
you will own capillary depth gauge

in our country I`d saw this one to sale on the diving exibitions
View attachment 488804

but my friend just made it by DIY way:
View attachment 488805

So, you can add like this to the snorkel and foget about it till better times

I would modify this to say that one atmosphere depth (2 ATM absolute) would mark half way up the tube (10 meters in freshwater or 33 feet of saltwater).

The other thing is that the tube, be it flexible or a long tube pictured, needs to be narrow enough in diameter that the water column won't break apart with a bubble between the water column.

Finally, note that the capillary tube depth gauge automatically compensates for altitude when diving at altitude.

SeaRat

 

[ystrout]

I ditched my snorkel a few months ago. I never breathed out of it and it was just one more thing to rinse off after diving.

As for the depth gauge, I don't even own one. I rely on my Puck Pro dive computer. It's possible my dive computer could run out of batteries during the dive or randomly break, but that's where a buddy comes in handy. Worst case scenario, she can guide me up to the surface and help me do a safety stop. And it's not like I wouldn't know how deep I was because I check my computer relatively frequently so I have a good idea of my depth at any point in time.

In reality, I would probably just finish the dive relying on her computer as long as we're not near our no-deco limits and each of us have the same dive profile that day.

My dive fiancé's computer actually locked her out once after the first of 3 dives in a day. We were on Catalina and she accidently went into free dive mode and then it wouldn't let her go back into scuba mode for the rest of the day. We did the other two dives relying on my computer. We just stayed close to each other and made sure I was deeper at any point in time than she was. No issues. If mine somehow broke while we were under, we would just swim to the surface...

 

[John C. Ratliff]

I mentioned above that the capillary gauge automatically corrected for altitude. The reason is that the capillary gauge will read deep. If you look at the table below, which I copied from various sources in the mid-1970s, you can see that at 4000 feet (about 1200 meters) the capillary gauge reading needs to be multiplied by 0.887 to get the true depth. So if I'm diving a lake at 4000 feet altitude, and my capillary gauge reads 30 meters (98.43 feet), I would log in my dive log 30 meters, then to correct it I would have to do the following calculation:

30 meters x 0.887 = 26.6 meters actual depth
or:
98.43 feet x 0.887 = 87.3 feet actual depth

But if I were using the U.S. Navy Diving Tables, which show for 100 feet a NDL of 25 minutes. But if we used the actual depth of 87.3 feet, the NDL would be 30 minutes.

If we used an accurate oil-filled Bounden tube depth gauge, we would need to add 4.7 feet to the depth reading, and then add a 3% correction factor. So if we were at 30 meters (98.43 feet) we would need to add 1.4 meters (4.7feet) to that reading, for 31.4 meters (99.83 feet), plus 3% for a depth of 34.3 meters (102.3 feet) depth. Note, that this would put the NDL higher, at 110 feet for 20 minutes using the U.S. Navy Diving Tables.

In the 1970s, we only had what was on this sheet for calculating altitude corrections. The Cross Tables for "Theoretical Depth at Altitude for Given Actual Diving Depth in Fresh Water" was a set of tables developed by E.R. Cross. If we had a line-measured depth, or a depth with correction using a depth gauge, we could use this table to determine which depth to use with the U.S. Navy Diving Tables. For instance, at 4000 feet altitude, we could dive to 100 feet, but would be best to use 116 feet as the "theoretical depth" for calculating NDLs or decompression. Table is quite out-dated, and should not be used currently, but I wanted you to see it to see how, in the past, we coped with altitude.

SeaRat

http://www.usu.edu/scuba/navy_manual6.pdf

 

[MaxBottomtime]

I still have my original depth gauge and bottom timer. I made a dive with them a couple of years ago and they performed flawlessly. Although I enjoy the information my computer gives me, it was nice to see that I could still dive without batteries.