Herman wrote:The DSV is not really for diving but for getting to and from the dive on the surface. As an example, a number of us do drift diving in Cozumel which often requires us to be on the surface for a good bit of time waiting for the boat to come pick us up. Without some way of shutting off the mouthpiece we are constantly fighting to keep the reg from freeflowing either by holding the MP under the water(occupies a hand), plugging it (must have one with you) or just keeping it in our mouths(can't talk). It is a pain to have to do any of those. If the reg had a DSV, we could simple switch it to off and not have to deal with freeflows. On the Kraken, it is just the next logical piece to make it as modern as possible.
I agree on improving the Kraken, but any feature overload would be detrimental to both the feeling and the reliability:
A DSV-mouthpiece is sticking out your mouth quite fairly and allows for increased leverage on your gums and teeth. It is a common problem on rebreathers, where you have to weigh down the hoses and use neckbands to take some stress off. It is also one of the major turn-offs of the Aqualung Mistral's mouthpiece. You basically need to use a big deep mouthpiece (JAX type) to counter the leverage generated by it sticking out so much.
Reliability wise, I am against any O-Ring that does not need to be. A DSV has at least two O-Rings that are under stress from friction. Add some grit and sand to that and you'll get leaks quite rapidly.
Equipment should never be an excuse for improper technique. Divers were taught for decades how to safely dive without a DSV.
I don't know if it was taught differently in the US, but in France you'd just put an arm through the breathing loop. That holds the mouthpiece at breast-level under the water and no free-flowing.
Personally, I do quite some dives where I wait to picked up too, but never needed that shut-off. You sit out your deco-stops under the SMB, and during that time the boat usually closes in on you. Once your done, you surface, swim those few meters to the boat and get out. There's actually very little time bobbing around on the surface. If I had to wait longer, I'd put my arm in the loop and switch to my snorkel. So if you ask me - no DSV!