dolphin mods and wob

**jmurba** · 6th January 2008, 12:24

Hi all,
I've dived my dolphin for long, and I never experienced any breathing problem.
in september 2006 I boutght 2 "L" :

at the beginning I noticed no change in breathing.
after a good 40 dives I can feel a WOB built up.

I check every thing in the loop that could cause the wob built up.

2 weeks ago I mesured the interior pipe diameter 26 mm

the original hose connections are 35 mm

the narrowest part of the dolphin loop are 29mm (the cannister connexions)

so in order to sum I've reduced the diameter of the 2 hose connexions from 35mm to 26mm can it really be the cause of my feeling of wod hardening keeping in mind that the dolphin has two 29mm passages ?

regards

jean mi

bletso · 6th January 2008, 13:15

The 90 degree bend may be more the issue. You have reduced the smallest diameter in the system from 29 to 26 mm. (not 35 to 26) Of course it may be its location. The 29mm orifices on the canister are not as important because on exhale there is a small CL and hydrostatic assist to go to the cannister and inhale lung. On inhale you are drawing from the inhale CL through the larger bore of the hoses connected directly from the CL, which has filled during your breathing cycle

I just ordered a 45. I need the 45 because my unit, due to my height and where it sits on my back has caused some very serious issues in high current and/or on a DPV. It lifts off my back, stretches the hose and causes a collapse. Very, very attention getting.

Has anyone else on this forum noticed any problems?

Jean Mi, have you disassembled the canister and cleaned the bottom screen? I did mine a while back and did notice a small difference.

Dale

4ster · 6th January 2008, 15:05

I have the elbow on the exhale side and a 3 cell holder on the inhale. I was initially concerned that WOB would be affected but couldn't tell the difference over the elbow-less configuration. That surprised me.

Are you saying that by removing the elbows from the loop you can feel the difference?

If you still feel a high WOB with the elbows off, I would check the bottom screen in the canister as Dale mentioned.

You are cleaning it and checking for dead squirrels in the loop, right?

**jmurba** · 6th January 2008, 20:26

Quote: (Originally Posted by bletso)

The 90 degree bend may be more the issue. You have reduced the smallest diameter in the system from 29 to 26 mm. (not 35 to 26) Of course it may be its location. The 29mm orifices on the canister are not as important because on exhale there is a small CL and hydrostatic assist to go to the cannister and inhale lung. On inhale you are drawing from the inhale CL through the larger bore of the hoses connected directly from the CL, which has filled during your breathing cycle

I just ordered a 45. I need the 45 because my unit, due to my height and where it sits on my back has caused some very serious issues in high current and/or on a DPV. It lifts off my back, stretches the hose and causes a collapse. Very, very attention getting.

Has anyone else on this forum noticed any problems?

Jean Mi, have you disassembled the canister and cleaned the bottom screen? I did mine a while back and did notice a small difference.

Dale

I Dale
I'll clean the screen it will mabye reduce the wob
don't know if the 90° angle is responsible for mu wob built up
I suspect the restriction....
regards
jean mi

**jmurba** · 6th January 2008, 20:31

Quote: (Originally Posted by 4ster)

I have the elbow on the exhale side and a 3 cell holder on the inhale. I was initially concerned that WOB would be affected but couldn't tell the difference over the elbow-less configuration. That surprised me.

Are you saying that by removing the elbows from the loop you can feel the difference?

If you still feel a high WOB with the elbows off, I would check the bottom screen in the canister as Dale mentioned.

You are cleaning it and checking for dead squirrels in the loop, right?

Hello
I have exactly the same conf then you in fact.
I can notice a wob built up only during efforts, not when swiming slowly.
it s encourraging to read that you noticed no difference.
however passing from 25 mm to 26 mm must make a difference otherwise why the hell would they have installed 36 cm hoses on the dolphin.
regards
jean mi

6th January 2008, 12:24	#1 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 859	dolphin mods and wob Hi all, I've dived my dolphin for long, and I never experienced any breathing problem. in september 2006 I boutght 2 "L" : at the beginning I noticed no change in breathing. after a good 40 dives I can feel a WOB built up. I check every thing in the loop that could cause the wob built up. 2 weeks ago I mesured the interior pipe diameter 26 mm the original hose connections are 35 mm the narrowest part of the dolphin loop are 29mm (the cannister connexions) so in order to sum I've reduced the diameter of the 2 hose connexions from 35mm to 26mm can it really be the cause of my feeling of wod hardening keeping in mind that the dolphin has two 29mm passages ? regards jean mi __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
(Online)

6th January 2008, 13:15	#2 (permalink)
bletso An independent diver. Current Rebreather/s: Dolphin Home Build Other Rebreather/s: Dolphin Home Build Join Date: May 2006 Location: Louisville, KY, USA Posts: 256	Re: dolphin mods and wob The 90 degree bend may be more the issue. You have reduced the smallest diameter in the system from 29 to 26 mm. (not 35 to 26) Of course it may be its location. The 29mm orifices on the canister are not as important because on exhale there is a small CL and hydrostatic assist to go to the cannister and inhale lung. On inhale you are drawing from the inhale CL through the larger bore of the hoses connected directly from the CL, which has filled during your breathing cycle I just ordered a 45. I need the 45 because my unit, due to my height and where it sits on my back has caused some very serious issues in high current and/or on a DPV. It lifts off my back, stretches the hose and causes a collapse. Very, very attention getting. Has anyone else on this forum noticed any problems? Jean Mi, have you disassembled the canister and cleaned the bottom screen? I did mine a while back and did notice a small difference. Dale
(Offline)

6th January 2008, 15:05	#3 (permalink)
4ster Steve Sprague Current Rebreather/s: rEvo Other Rebreather/s: rEvo Join Date: Mar 2006 Location: Arlington, Washington Posts: 295	Re: dolphin mods and wob I have the elbow on the exhale side and a 3 cell holder on the inhale. I was initially concerned that WOB would be affected but couldn't tell the difference over the elbow-less configuration. That surprised me. Are you saying that by removing the elbows from the loop you can feel the difference? If you still feel a high WOB with the elbows off, I would check the bottom screen in the canister as Dale mentioned. You are cleaning it and checking for dead squirrels in the loop, right? __________________ Steve "My problem is that I have trouble reconciling my gross habits with my net income." Errol Flynn
(Online)

6th January 2008, 20:26	#4 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 859	Re: dolphin mods and wob Quote: (Originally Posted by bletso) The 90 degree bend may be more the issue. You have reduced the smallest diameter in the system from 29 to 26 mm. (not 35 to 26) Of course it may be its location. The 29mm orifices on the canister are not as important because on exhale there is a small CL and hydrostatic assist to go to the cannister and inhale lung. On inhale you are drawing from the inhale CL through the larger bore of the hoses connected directly from the CL, which has filled during your breathing cycle I just ordered a 45. I need the 45 because my unit, due to my height and where it sits on my back has caused some very serious issues in high current and/or on a DPV. It lifts off my back, stretches the hose and causes a collapse. Very, very attention getting. Has anyone else on this forum noticed any problems? Jean Mi, have you disassembled the canister and cleaned the bottom screen? I did mine a while back and did notice a small difference. Dale I Dale I'll clean the screen it will mabye reduce the wob don't know if the 90° angle is responsible for mu wob built up I suspect the restriction.... regards jean mi __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
(Online)

6th January 2008, 20:31	#5 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 859	Re: dolphin mods and wob Quote: (Originally Posted by 4ster) I have the elbow on the exhale side and a 3 cell holder on the inhale. I was initially concerned that WOB would be affected but couldn't tell the difference over the elbow-less configuration. That surprised me. Are you saying that by removing the elbows from the loop you can feel the difference? If you still feel a high WOB with the elbows off, I would check the bottom screen in the canister as Dale mentioned. You are cleaning it and checking for dead squirrels in the loop, right? Hello I have exactly the same conf then you in fact. I can notice a wob built up only during efforts, not when swiming slowly. it s encourraging to read that you noticed no difference. however passing from 25 mm to 26 mm must make a difference otherwise why the hell would they have installed 36 cm hoses on the dolphin. regards jean mi __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
(Online)

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