Appeared in DIVER February 2007

REGULATOR  Seac Sub Synchro D
The idea behind dry sealing is that it will keep out water contaminated with detritus or pollutants. A regulator might not function correctly if it is jammed up with gunge.
Detritus found in the sea is easily dealt with - you wash it away when you rinse in clean fresh water. However, the only sure way of avoiding accidental aspiration of polluted water is to stay out of it.
Some say that dry-sealing stops freeze-ups because of the way water is kept away from the works, but others suggest that the air and mechanism of the regulator needs to be warmed up, and the only source of heat is the water surrounding it.
If you find that hard to believe, bear in mind that the fresh water of an inland dive-site in winter might be at only a few degrees C above zero, but the air depressurising from the tank will be at many degrees below that!

ONE WELL-KNOWN MANUFACTURER that produces regulators made with metal for good heat-sinking qualities still sells optional environmental kits - and has even renamed these coldwater kits.
The new Italian-made Seac Sub Synchro D (D for diaphragm) has an environmentally dry-sealed first stage that is reminiscent of some of those popular products from Lancashire. As such, it is perfect for swimming in water thats like warm minestrone. It has four angled medium-pressure ports and two high-pressure ports spaced so closely together that there was insufficient room for me to fit a radio-linked pressure transmitter for my computer. I had to use an extension piece.
It will be equally difficult to fit hoses with heavyweight hose protectors in the space provided.
The second stage is an all-plastic affair that makes little concession to coldwater diving, though it has a slim metal trim.
The purge button is hidden behind a large soft shroud, so its easy to find and use. This shroud unscrews in a satisfyingly precise way to reveal a nicely finished front diaphragm and valve mechanism. The manufacturer should have no qualms about its customers looking in here and feeling cheated.
The Venturi plus/minus switch operates a very small flap that is introduced into the airflow at the mouthpiece. Interrupting the airflow here discourages exponential free-flows. However, it was so small that I decided only a highly sophisticated machine would be able to tell the difference in performance between the two settings, so I left it at the minus setting.
That was just as well, because I found it very hard to get at with a gloved hand. There was never any shortage of air supply at any depth and it never fluttered or over-fed me when I heaved on it during moments of high excitement.
The mouthpiece was exceptionally comfortable but the exhaust-T was, as is fashionable, a little small. I suppose that if you always dive in a group and spend your time hurrying to keep up with the dive-guide you dont notice any problem, as forward motion dispels the bubbles. But if you stop to look at things, your exhaled bubbles will disrupt your vision.
Seac Sub is one of those companies that has been making steady inroads into the scuba-diving market by demonstrating an improvement in the quality of its products over
the past half-dozen years. The Synchro D represents a serious attempt to break into the lucrative mainstream regulator sector.
The Seac Sub Synchro D costs 249.
  • Beaver Sports

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    + Good alternative to established dry-sealed regulators

    - No track record