Newbie Needs Help!!!!

[Aegir]

I have owned some of the top regulators in my time, but i see Apeks as the best by some distance..in both breathing ease at depth and sheer dependability.

 

[Kevin]

Go with Apeks for regulators.
A popular set up with me and the people who I dive with is the TX50 as a primary second stage and the TX40 as the octopuss reg.
As for BCs, I have just bought a Apeks SB2000 and think that it is brilliant. It is very comfortable to wear and has integrated weights.

 

[tgreaves]

Turnerjd.. I can see where scubapro is coming from.. If the water temp is 40 deg.. The reg might freeze up at 0 deg because of the air running over small areas.. So if there is 40 deg water hitting 0 deg metal.. Its going to warm it up closer to 40 deg..

 

[turnerjd]

Originally posted by tgreaves
Turnerjd.. I can see where scubapro is coming from.. If the water temp is 40 deg.. The reg might freeze up at 0 deg because of the air running over small areas.. So if there is 40 deg water hitting 0 deg metal.. Its going to warm it up closer to 40 deg..

tgreaves,

Personally I don't see where scubapro are comming from. In *centigrade*, if the water is 2-4 degrees (a tad above freezing) then the metal in the reg will equilibrate to roughly this temperature, as the water is a GOOD conductor of heat. If we consider the start of the dive, with the diver bobbing about on the surface, then tank, air inside, and reg will all be roughly at water temperature.

Now, as a dive progresses we use the air, as gasses expand they cool (fundamental physics). So, if we have a reg at just above freezing, with water in it, then the expanding gass will cool the whole of the first stage to possibly below freezing, and as there is water in there you will end up with a frozen reg (if you have a scubapro).

This is best demonstrated by sitting at home breathing off a reg, or even just holding down the purge button. as the tank pressure falls you will feel the first stage get pretty cool, if you do it somewhere warm and humid you should see condensation on the outside of the first stage. This temperature drop can be as much as 15-20°C out of the water, and with the water there constantly AGAINST THE METAL BODY (not necessarily inside) will reduce this to about 5-6° Centigrade difference (1° C = approx 2°F for this range)

For me, it is more telling that the people that make the regs that get real use and abuse (poseidon and apeks) think the opposite of scubapro.

They take the line that - if everthing is roughly at water temperature at the start, then, as it cools with the gas expanding, then to avoid any freezing, you don't want any water in there at all. Sherwood take this a bit further and have what (if it works correctly) is an active elimination system, in that air is bled out of the first stage taking any moisture away with it. However, this is fundamentally flawed in that the expanding air is cooler than the reg and ambient temperature, so rather than warming the first stage to ensure it stays above freezing, they are actually cooling the reg further.

To eliminate freezing, it is more obvious to me that if there is no water in the reg, then there is nothing to freeze, and if there is nothing to freeze you can't have a problem. - I think that if the first stage were to be fitted with cooling fins on the outside, then these would help maintain the reg at local temperature, and that it would overcome to some point the drop in first stage temperature as the air expands, in this, the scubapro UL regs are going the wrong way in that they are using a less thermally conductive material.

Please note, this is just MY analysis, and represents my opinions, nothing else!

Jon T

PS if the water is 40Deg as you say (40 F = 4C????) then the reg body will be not too distant from this, it certainly won't be at 0F (-21C) it could easily be at 30F or so, but it will certainly be quite a bit (upto 12°F, 6°C) lower than the water, and quite possibly below freezing. (eg in 4°C, it is quite possible that the reg body would be cooled to -2°C, 2°C below freezing)

PS2 The article I mentioned also asked the owner of the main inland diving site in the UK which theory was bourne out by the number of free flowing regs he saw..... he thought that Apeks etc.. were on the money, and that Scubapro were off the mark. - note, the water there in the winter is often just above freezing (2°C often seen in the winter) and is fresh, so will freeze more easily than salt water.

PS3 sorry if I have F - C conversions screwed up. I only ever use Centigrade or Kelvins