Soggy
Contributor
Nemrod:DIR does not always imply doubles?
If you are in an overhead environment (i.e. mandatory deco or hard overhead), you need doubles, end of story. So, for a 150ft or 180ft dive, it's a no brainer---you need doubles. For recreational profiles, you just need enough gas to get you and a buddy to the surface and still have enough to do a reasonable dive. That might mean doubles, it might mean large singles, depending on depth. Once you start taking a real hard look at rock botto gas planning for you and a buddy in depths around 100ft, you'll find that an Al80, for example, is not enough gas to do a dive of any reasonable duration. That's part of why you see a lot of recreational divers using doubles for anything even remotely deep.