Now, THAT'S a Light! Weight, placement & balance?

[rsdancey]

I've acquired an old Halcyon cannister light to continue my experimentation with a DIR rig. Opened the box last night and discovered that what I thought was going to be a "big" cannister is a FRICKIN' HUGE cannister.

It's an Explorer 50, and the unit itself is roughly the 3/4 the size of a Duraflame fire log!

I'm still diving in a wetsuit here in the Pacific NW (have not yet gotten "cold" enough to feel a drysuit was worth the price, even diving in the winter months), so I'm carrying a lot of weight to offset the thick neoprene (7mm) I'm 6'6", and weigh about 245lbs. Currently, I'm diving with 20lbs in my Zeagle Ranger BC weight pockets, and 20lbs in a belt, and I'm still somewhat underweight when diving with an AL80.

My in-process DIR rig is a SS backplate & wing. I have not yet dived with this configuration and have not yet had time to experiment with weight and trim.

Now to the questions:

1) I've noticed that the OMS system seems to encourage attaching the cannister to the backplate, while the Halcyon system does not. I assume Halcyon's strategy is to permit the diver to ditch the light if necessary to reduce weight or clear an obstruction. My first question is "how does one keep the light from sliding forward along the webbing if the light is not attached to the backplate?" My second question is "Would it be DIR to attach the cannister to the backplate?"

2) This particular light weighs a lot. (good, in my case). However, securely tucked away on my right side, that means I've got a potential balance problem. I considered an unequal weight distribution on the weight belt, but on second thought I believe that will cause the belt itself to shift. My third question is therefore "how do I distribute weight & gear to achieve a balance - what's the DIR configuration that doesn't involve stage tanks?"

Any insights would be greatly appreciated!

Ryan

 

[do it easy]

Now to the questions:

1) I've noticed that the OMS system seems to encourage attaching the cannister to the backplate, while the Halcyon system does not. I assume Halcyon's strategy is to permit the diver to ditch the light if necessary to reduce weight or clear an obstruction. My first question is "how does one keep the light from sliding forward along the webbing if the light is not attached to the backplate?" My second question is "Would it be DIR to attach the cannister to the backplate?"

2) This particular light weighs a lot. (good, in my case). However, securely tucked away on my right side, that means I've got a potential balance problem. I considered an unequal weight distribution on the weight belt, but on second thought I believe that will cause the belt itself to shift. My third question is therefore "how do I distribute weight & gear to achieve a balance - what's the DIR configuration that doesn't involve stage tanks?"

Any insights would be greatly appreciated!

Ryan

I can't answer all your questions, but the light is on the waist strap held on with a weight buckle.

As far as the balance goes, it never seems to be an issue. I think once you adopt the DIR philosophies, you should be able to breathe using only one side of you lungs and balance yourself. Seriously, in some miraculous way, it seems to balance itself out. I've worn a stage and a deco bottle (both 80's- full and negative) and didn't notice any change in trim. The physics says that I should be listing to one side, but somehow I managed to stay level. My guess is that subconsciously, I contract/relax muscles in my back or something to keep everything squared away.

Hopefully, someone else will answer the rest of your questions...

 

[Jasonmh]

Well, I don't have a canister light yet, but some of the people I know use an extra SS buckle (like the one used on your harness). They slide the light on the right side waist strap first, all the way back until it is touching the plate, then slide the extra buckle right up to the light and clamp it down. Then when they are horizontal in the waterit stays put, but is easier to get off than using a tri-glide.

"My first question is "how does one keep the light from sliding forward along the webbing if the light is not attached to the backplate?"

 

[Soggy]

My first question is "how does one keep the light from sliding forward along the webbing if the light is not attached to the backplate?"

Use a stainless weight belt buckle....although with that big a cannister, you likely don't need an extra buckle.

My second question is "Would it be DIR to attach the cannister to the backplate?"

No...everyone on the team is configured identically. To mount it on the backplate and be able to hit the switch, it needs to be upside down which changes the cord routing as well as making it more likely to get damaged. Back there, you cannot ditch it in an emergency, either.

My third question is therefore "how do I distribute weight & gear to achieve a balance - what's the DIR configuration that doesn't involve stage tanks?"

You don't worry about it...thankfully, the laws of physics are on your side and you just end up with more gas in one side of the wing than the other.