Trim really isn't an issue if you're using a Halcyon wing, especially if you're using Apeks regs with hoses routed GI3-style, because the (moderately) restricted airflow through the narrow top section allows you to distribute the air unequally to compensate for the weight of deco or stage bottles, or a cannister light with none. I can maintain perfect lateral trim at all times by shifting air from side to side.
Rigging for 2 left deco tanks
- Thread starter MechDiver
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I have a question for you regarding your trim techniques. I will try and word it carefully so as not to create a DIR vs others question.
I have heard several DIR divers mention that they control their trim of diving with their tanks on the left by moving the air in their bladder to that side.
It would seem to me that a flat profile with air equally distriputed throughout your bladder would be a preffered. it seems that to keep the left side of your bladder more inflated you would need to tilt slightly or maybe greatly.
if you had three tanks on one side then you would have an extra 20 lbs negagtive on that one side, that is a lot of air on one side of your bladder. and a lot of weight on just one side. imo
Just a quick thought. if you had on bunggied wings you can adjust your trim by tightning the bungies on one side and loosening them on the other this would allow a flat profile while in the water. just something that occured to me while typing this.
Now since it is DIR not to have a reddundent bladder [if drysuit diving] what happens to that air shift if your bladder fails it doesn't seem that shifting it in your dry suit is that feasable....but i guess it could be done.
i use a very small canister light as seen here http://www.diverite.com/products/lites/nimh.htm
so there is not that much offsetting weight.
for all those who are trolling I am not looking to start an argument, i am somewhere between DIR and Non DIR and ask these question sencerely, as this is one area that i can't get my head around to find the benifit
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I don't intentionally offset things with uneven air in my wing. I wear 2 deco bottles, aluminum 40s, on the left and my smallish can light on the right (Pro 4 HID). I don't find the deco bottles cause any real balance issues underwater. If they were steel or larger aluminums it might be a different story though.
I use Apeks regs and the hose routing does cause some restriction in flow across the top of my wing but its not really noticable in my opinion.
I think if one is weighted correctly and balanced underwater there should be minimal air in the wing at any time at depth. I virtually never feel any shifting of my trim due to air flow within my wing.
Tom
I use Apeks regs and the hose routing does cause some restriction in flow across the top of my wing but its not really noticable in my opinion.
I think if one is weighted correctly and balanced underwater there should be minimal air in the wing at any time at depth. I virtually never feel any shifting of my trim due to air flow within my wing.
Tom
WYDT
Contributor
I dive DIR (Cave) and don't have to move air to one side or the other to maintain trim....
If you use Luxfer tanks and use correct rigging and regs for stages/deco bottle they won't be overly negative and won't make a difference how many you hang on the left side.
I had two stages (AL80's) and an AL40 O2 bottle on the left this past Saturday... no problems with trim and no need to "shift air". You just have to use the right bottles rigged the right way and have the regs set up correctly.
This is not directed at anyone in particular but one can't "half ass" be DIR like just hanging bottles on the left. It's the whole system that makes it work.
Those who claim it doesn't work likely don't really know what it's about.... or how it really works....
The more I learn about DIR the more I KNOW it works. It's the WHOLE system... not parts.
DSAO!!
I have carried as many as three al 80's on the left with no trouble. If anything, when all tanks are full I may be slightly head heavy (double 104's FULL on back).
OP
Could you share the information on how the bottles should be rigged and how you setup the regs? I would be very interested in details here.
Thanks
Phil
WYDT
Contributor
Sure.... here are some links that should help out....
http://www.northeastdir.com/images/pages/stage_close_2.htm
http://www.wkpp.org/articles/Gear/equip_moreimages_3.htm
http://www.gue.com/equipment/equip-anatomy.shtml
http://www.gue.com/equipment/jj-hogarth.shtml
http://www.gue.com/equipment/tanks-4.shtml
Maybe those of you who don't notice the imbalance have less restriction and even out without conscious effort? I find the effect of even a single deco bottle noticeable and find that I am more comfortable if I purposely shift air to that side. I clip on a bottle and am a bit heavy on the left, I lean to the right to shift air left and I'm balanced. Hmmm. Maybe I'll try it with different regs to see if it is the restriction.
OP
Thanks for the links. I had all of them except the first, but it was nice to read JJ's article again anyway.
Phil
OP
I'm using SP regs with the Explorer wing and, even with argon and one deco bottle (40) on left, I seem to just adjust to it. One on each side was the same after getting used to the added bulk. I really notice no air shifting, or have to lean one way or the other to balance.
Phil
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