Large bore hose and regulator combinations

[muddiver]

I know there are a couple of different size ID low pressure hoses out there to feed the 2nd stage from the 1st stage.

I usually dive either a Sherwood Blizzard or Brut with the matching 1st and 2nd stage and a generic LP hose. I found that on some dives when I am either having to keep up with a human torpedo or catch up with a group when doing photo work I can and do over breath the regulator. I know it is not due to haw they are tuned, it can happen at all depths.

Question is, there are a few regulators out there ( I now have a Kirby Morgan Superflow 350 ) that have a large bore LP hose and ports. Does anyone know if the larger size hose will make up for the higher volume demand during heavy work without using a large bore 1st stage?

 

[paulwlee]

According to my reading of these and other boards, 1/2" hoses really have little if any noticeable advantage over 3/8" hoses. In fact, many regulators that have 1/2" fittings have 3/8" hoses with 1/2" fittings, and Aqualung, whose high end models have had the 1/2" port for more than a decade, has just phased them out. (BTW, my first regulator 15 years ago was a U.S. Divers -old Aqualung- Conshelf SE2, the only difference with the cheaper Conshelf 22 being a 1/2" hose. Never noticed a difference, and with a stiffer -and less commonly available- hose and added cost, it sure was good money wasted.)

If overbreathing is a problem, I suggest you try out some of the regulators that are touted as the best performers. The non-budget models from Scubapro, Atomic, Apeks, Aqualung, etc.

 

[spectrum]

Hi muddiver,

As paulwlee stated this came up in a thread about 2 months ago. The consensus was that it had little meaningful effect. The theory is good but the delta between IP and delivery pressure already provides a lot of air just in the hose. The idea of having an accumulator is a good one it just has no real value in this case.

Make sure that your first stage dry bleed is still passing some air. If not then the check valve has closed and you are not balancing. This means that IP will not rise and you will work for air. This will be worse deeper but will have some impact even in the shallows.

Take the lead or get another buddy.

Pete

 

[muddiver]

Thanks for the comments. I suspect that the little filter in the piston is not bleeding enough air through to keep the first stage ballanced.