overpressure valve

escott

does anyone know where to get a good read, or have any advice on how to set the overpressure valve on a dolphin. Not much on it in the manual on recommending how to set it.
Low means low loop volume, low bouyancy but more chance of hitting bypass. High means high loop volume, high bouyancy with less chance of hitting bypass. Anybody got anything else?

Scott

Bosh

More loop volume means more oxygen in the loop, means less variation in percentage, if you work harder for a short while.
Propably more a theoretical issue though.

I personally prefer the OP valve set to low volume. Dont like too much resistance on exhalation. Nor the added weight.

I dive my Atlantis 6 clicks back from fully closed, but valves vary, so try for yourself. Mine wents on each exhalation.
To my knowledge Dolphins has less number of clicks.

I know some people will disaggree, prefering fully closed, and only venting once in a while, but i guess you already read through previous posts .

Best regards

Bo

firemandiver

Scott, I've found if it's all the way to the right the breathing on exhale is very hard, but it doesn't burp bubbles as much. Conversely, all the way left is very easy breathing but exausts more bubbles. I generally set mine in the middle, about 3 clicks, and it is a happy medium. I've also found that regardless of the OPV settting, deep exhalelations are gonna burp off bubbles so my thinking is why make it harder to breathe than necessary? During the dive I will intentionally exhale very deeply a few times to make the OPV purge. That lets me know at depth that it's working properly. Hope this helps. FD

Freef

It depends if you are shallow or deep diving as well, and how scared the fish get if that's what you are trying to see.

In the shallows [12m or less] it's recommended that you dive with it fully open, in the depths [12m+] closed to suit the diver.

As the first stage is nin compensating, you are adding the same surface ammount of gas per minute. At the surface on the 60% jet you will add 5.8L to the loop, at 30m this will be 1.45L because of the compression factor. So at depth the Dolph will dump less.

You can also push your shoulders forwards as you exhale to dump a bit more gas ig you need to.

Personally, I dive with the dump fully closed, most of my dives are below 20m.

__________________
David.

Currently owner of two differently sized ankles.