<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi,<div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 12 Oct 2015, at 09:17, Rick Walsh <<a href="mailto:rickmwalsh@gmail.com" class="">rickmwalsh@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">Thanks for the explanation. My understanding/definition of reserve gas is the minimum gas you plan to have at the end of the dive. The reserve needs to be enough to cope with something going wrong, such as your buddy being out of gas at the start of the ascent, then have more left over.<br class=""><br class=""></div><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">I think either way is fine so long as it is documented.</div></div></blockquote></div><br class=""></div><div class="">I agree it should be documented better. But the rationale is as follows: You need to bring your buddy to the surface and that could mean gas sharing. How much gas is used in sharing of course depends on the depth ascent. This can be a bit hard to estimate, so most agencies teach to assume a fixed amount of gas, or actually of pressure (40 or 50bar or 25% or 33% (rule of thirds) or whatever). But we can do better, we know about the ascent and that is why we add the amount of gas during the ascent (i.e. the "deco gas“). We still have a fixed pressure „reserver“ but that is supposed to be for the gas that you use around the realisation that you have a problem where your pulse goes up and you start to buddy breathe. So this is user configurable.</div><div class=""><br class=""></div><div class="">Maybe Willem can add something along these lines in the manual.</div><div class=""><br class=""></div><div class="">Best</div><div class="">Robert</div></body></html>