On Saturday, March 20, 2004 5:01 PM, Andy wrote:

(snip)
>  I did a bit of trawling the wibble to get some figures for Red Sea
>  salinity & density & came up with the following:

> Red Sea salinity is about 40 parts per thousand (ppt) compared to the
> average ocean salinity of 34.7 ppt. These figures relate respectively to
> relative densities of about 1.027 and 1.022 (at 25DegC). Using these
> figures, a fully kitted diver weighing 250lb (a lot !!) would need an
extra
> 1.25lb of negative buoyancy, or approximately 1.25lb of lead.  So much for
> my gut feel of a few ounces. But this figure is a lot less than most Red
> Sea Dive Masters / Instructors would have you believe you need. I was
> actually prompted to find out a bit more on this from an article in Diver
> magazine where a Red Sea 'dive guide' claimed the Red Sea had  'double the
> salinity of your average sea water' and divers required 2-3 kg more lead
> than in other warm waters.

Mate!  You should have bought a, "Weigh-2-Go" weighting system from me
before I put the price up and beyond most people's reach.  It would have
been perfect.  :-)

Strike

'Weigh-2-Go'
For The Travelling Diver

For those divers who, when travelling, prefer the convenience of using their
own equipment, Zymurgy Inc., have developed a range of portable weights that
won't put your airline baggage allowance over the top!

The brain-child of Zymurgy Inc.'s Senior Design Engineer, the 'Weigh-2-Go'
series features 1, 2, 3 and 4 kg weights in a variety of mix-'n'-match hues
for complete colour co-ordination with the rest of your diving equipment.

Constructed from sturdy polypropylene the 'weights' are hollow containers
marginally larger than the 'normal' lead variety and contoured to mould
themselves comfortably to the body.  Each canister features two low profile,
screw-top, filling caps, one allowing ingress of water while the other
permits the escape of residual air.

Threaded onto a conventional webbing belt the whole unit is lightweight and
easy to carry until required for use.  Once at the dive site the user simply
fills the containers with the water into which they will dive, either salt-
or fresh.

The beauty of the Zymurgy Inc., 'Weigh-2-Go' weighting system, is its
ability to quickly adapt to any density of water without the need to add or
subtract weights from the main component.

It must be remembered, however, that a 'filled' unit is only completely
valid in water conditions approximating, or identical, to that within the
container.  As an example, fresh water - weighing
approximately 3.00 Kpa - is considerably lighter than ocean water that
weighs about 3.07 Kpa.  Diving with fresh-water filled 'Weigh-2-Go' units in
the ocean will give a normally perfectly weighted diver positive buoyancy.
Whereas a diver using salt-water filled 'Weigh-2-Go' weights in a
fresh-water environment will be negatively buoyant.

A minor consideration when viewed against the advantages of carrying your
own perfectly weighted system with you whenever you travel.