We are about to start teaching it and you must have missed the required equipment bulletin. You don't carry 2 snorkels, duh! The special snorkel required for the class has a standard mouthpiece and then another mouthpiece coming out of the other side on 9' of corrugated hose. Just grab it off the bottom, drag it up in front of you, and donate the other end to your OOA buddy. They may also need to take the 9' snorkel clearing specialy class...it can be quite difficult if you are too shallow to use the displacement method.detroit diver once bubbled...
But then you'd have to carry 2 of them in case your buddy goes OOA.
The snorkel lists for $699