Mailing List Archive Mailing List Archive
Richard
>Terho Kaikuranta writes:
>Although the first stage
>was covered with 1 cm layer of ice
That I reckon is the reason for first stage to be sealed
>Just to remind you if you missed it
>So the best bet for cold water diving will be DV :
>- Environmentally sealed first stage
>- the bigger the first stage the better (heat transfer)
>- preferably regulated second stage (like in some of Apeks or
>Scubapro models)
> on some occasions free flow at second stage can be stopped
>by increasing spring load (winding in )
>- Less plastic bits used for first and second stage construction
>will give you better heat exchange properties
>- Some of the DV's have got small heat exchangers
>incorporated in the second stage those may help but not a lot.
>(Apeks TX50, Spiro Supra Arctic)
>- Use specially designed heat exchange devices to be
>mounted on any DV to increase freezing resistance (That in
>future - although I have been able to dive preproduction
>model of such device -- is really good)
As I already wrote I have not seen yet a DV which will perform in
cold water as one would like to
Definitely POSEIDON managed to produce v. good
first stages but for example Apeks TX50 is very similar but
being sealed it is v. good one as well.
Why Odin-Jetstream is behaving like you described is
probably to do with specific construction of the second stage
But in our tests we managed to freeze it as well (ODIN)
As regards seawater versus freshwater that one you
almost answered yourself: freezing temp. of seawater
is lower than that for freshwater, and of course depends on the salinity.
Which stage will freeze in which water is rather to do
with specific construction details (sealed , or not, lot of plastic bits).
But if your air supply is good and dry and first stage
is sealed you should expect problems only at the second stage.
Gregory
G.Kowalski -- UHAP010@VM*.RH*.AC*.UK*
Navigate by Author:
[Previous]
[Next]
[Author Search Index]
Navigate by Subject:
[Previous]
[Next]
[Subject Search Index]
[Send Reply] [Send Message with New Topic]
[Search Selection] [Mailing List Home] [Home]