we used to try just a tube from the surface down but it's limited

[Doc Harry]

we used to try just a hose down from the surface but it's limited dew to the lung capacity and out side air pressure and depth pressure so its just turns out to be a long snorkle and not diving .

That has been tried unsuccessfully for hundreds, if not thousands, of years. Without pressure, you can't get very deep.

 

[duckbill]

Without pressure, you can't get very deep.

Yeah, as in 3 or 4 feet maximum, IIRC from my "experiments". Good workout for the diaphragm, though.

 

[skeatesy]

..with out getting of the track since i had freinds who used proper diving 'bell' and were not unnerved by the deep i stuck to just snorkling in the end because of fear of benz and stuff ..but i got very good at holding my breath at byron bay nsw australia out at the wreck off main beach as practise makes perfect and i could get deeper and i got less scared of sharks and when i was going out one morning a i saw a bronze coloured coin i thought was a 2cent piece so i left it till i came back and it was where the old walf used to be and as it turned out when i retreaved it going back to beach after snorkling a coin dealer gave me $100 for what was a gold soverien and it was reported in the byron newspaper .some one a hundred years ago lost it off the old walf and i found it ..luck ..

 

[ktomlinson]

When I was around 10 I stayed under in our pool for 5-10 minutes with my brother pumping air using a foot pump... I guess it was in about 6' of water.

 

[Akimbo]

we used to try just a hose down from the surface but it's limited dew to the lung capacity and out side air pressure and depth pressure so its just turns out to be a long snorkle and not diving .

Limited? You just forgot the compressors and tube trucks. Read the directions man!