Rebreather World - View Single Post

AD_ward9 · 29th May 2008, 16:04

Quote: (Originally Posted by paulraymaekers)

I agree that WOB must be lowered, clear.
Problem is that we try to match it with what a reasonable fit large male can do for some time: 75l/min, and even more, at depth. So here we start having some 'discrimination'

you start designing to meet the limits, and mostly as a consequence the unit becomes 'bigger': bigger hoses, bigger mouthpiece, larger volumes. Al this means you get a heavier unit, with often more drag under water.

now here comes a 50kg, 1.55m female diver who want to start diving CCR, and wants do buy a unit that meets the safety limits....

?? how many small female boris divers are around?

regards

paul

The difference in drag from low WOB features, is absolutely minute. A few mm on a hose diameter, a few mm on a mouthpiece, use of a single layer counterlung construction, use of either EACs or a radial instead of axial granular scrubber, minor changes to connectors, use of lower durometer flapper valves etc. It might add up to 150 grams of extra weight, but that is about all.

There is some extra volume needed, but under a litre.

Alex

29th May 2008, 16:04	#558 (permalink)
AD_ward9 So much more to learn Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jun 2005 Location: Scotland Posts: 1,732	Re: Comprehensive list of all accidents Quote: (Originally Posted by paulraymaekers) I agree that WOB must be lowered, clear. Problem is that we try to match it with what a reasonable fit large male can do for some time: 75l/min, and even more, at depth. So here we start having some 'discrimination' you start designing to meet the limits, and mostly as a consequence the unit becomes 'bigger': bigger hoses, bigger mouthpiece, larger volumes. Al this means you get a heavier unit, with often more drag under water. now here comes a 50kg, 1.55m female diver who want to start diving CCR, and wants do buy a unit that meets the safety limits.... ?? how many small female boris divers are around? regards paul The difference in drag from low WOB features, is absolutely minute. A few mm on a hose diameter, a few mm on a mouthpiece, use of a single layer counterlung construction, use of either EACs or a radial instead of axial granular scrubber, minor changes to connectors, use of lower durometer flapper valves etc. It might add up to 150 grams of extra weight, but that is about all. There is some extra volume needed, but under a litre. Alex Last edited by AD_ward9 : 29th May 2008 at 16:08.
(Offline)