rgadt wrote:There is a guy on YouTube that does full mud submersion with a gas mask fitted with a breathing hose and some sort of canister/float on the end of the hose, and seems to have fairly good success with it. If you do some searching there you should be able to find them pretty easily.
rgadt
One thing to keep in mind is that if you both inhale and exhale through the same hose beyond a certain length, you will slowly suffocate due to buildup of carbon dioxide inside the hose, because you would have to inhale deeply enough for fresh air to come in from the end of the hose and reach your lungs, making something longer than a foot a bit risky. So, I inhale through a hose only, and exhale through my nose, into the mud, although I also both inhale and exhale through a pvc pipe, but it is only a foot long. But, perhaps a valve setup with two hoses could be made so that when you inhale, the air flows to you through one hose while the other hose is blocked off, and when you exhale, the hose you were inhaling through gets blocked, and the other hose opens up to expel the carbon dioxide you exhale.