Plan your dive and dive your plan. Well this is what both Chris and I thought we were doing. We were just coming up from a very pleasant 40 minute dive on the Kyarra expecting 15 minutes of deco (BSAC 88). This was not at all the case as both of our computers were asking for around 40 minutes! We compromised and did 30 minutes of this (not ideal) before we gave up and headed back to a rather displeased skipper. We were well over our dive time by this stage! It was fortunate that we had gone a bit overboard with the amount of air we took with us allowing us to spend the extra time in deco without running out.
So what had gone wrong? You may think we went for deeper or longer than we had planned with tables, or perhaps we just messed up the plan altogether? Well, this is not quite the case. As it turns out, both of our computers are a lot more conservative than tables for deco diving. This was confirmed by using the “simulate dive” feature on them the next day.
Moral of the story? If you are deco diving with a computer, simulate it on the computer before the dive so that you know what to expect!