Need BC to stabilize heavy tank

[spoolin01]

My main dive partner just moved up from Al80s to Faber HP100s - well it was a forced upgrade really: I dive LP120s and hated leaving the water with so much air left. The Fabers are 14 lbs negative when full and just wouldn't stay put during the dive. She was clearly distressed at the constant struggling and the pressure of the tank on her soft weight belt which is bulky (7mm drysuits, lots of lead). She has a standard jacket BC with cummerbund and no chest strap, where the tank mates to a small hard plate with one strap. I don't recall the model at the moment but it's low end. I suggested a backplate and wing might work better, but she likes having pockets. Given time I think she'd appreciate the BP/W the way I do, but for now... I think having the inflation separate from the harness would improve things, and back inflation would help her maintain upright position on the surface - she said she was being pulled backwards. Can anyone suggest a back inflation or other BC that would do a better job of immobilizing these tanks? She's tall and wears a Men's medium - women's BCs are too short in the waist. I think she'd prefer non-integrated - the tank alone is heavy enough, but I gather integrated is how they're built. Is a second tank band an indicator that the hard pack is a little longer and less likely to torque? Any help would be greatly appreciated - I want to keep these tanks!

 

[spectrum]

She was clearly distressed at the constant struggling and the pressure of the tank on her soft weight belt which is bulky (7mm drysuits, lots of lead).

She has weight between her and the cylinder? This sounds like a good place to start. If she has lead way up on her spine and a more negatively buoyant cylinder than ever her center of gravity is up on top and diving is like riding a unicycle on the high wire. I'd get that lead down onto the sides. My DUI Weight & Trim II does a nice job of carrying the weight with my similar drysuit. Putting the weight down in the "saddle bags" really helps. Also with the weight moved the cylinder won't be perched up there so high.

Most BCS's today are integrated except mainly or some entry models which are not necessarily low end or unsuitable. Just because A BC has weight integration nothing says she needs to use it. Over 90% of the time the only weight in my BC is up in the trim pockets.

As for bands you need to check. My Sherwood Avid is a two bander but has very little structure below it.

If she's a second time buyer, in a drysuit a BP&W may be the best next step, has she at least tried yours? Other than being light on features how well does hers fit? Any BC that fit's like a poncho is useless.

Pete

 

[spoolin01]

If she has lead way up on her spine and a more negatively buoyant cylinder than ever her center of gravity is up on top and diving is like riding a unicycle on the high wire.
Pete

Lol - maybe I'll just give her a big pole to swim with!

As well the inflated BC puts major bouyancy underneath when swimming (she likes to overweight which also is on the list of issues). With less weight on her belt, maybe she can use just the side pouches - ha, ha she did say she just left her belt where it was when it slid around underneath her - but nylon weight belts are a whole 'nother topic. I've suggested she try my wing setup and am looking for a BC made in wing style so she can have those pockets... I've never understood why anyone would want more weight in their BC and not strapped tightly to their body, but weight integrated construction is certainly the rule. Maybe for warm water diving it's less of an issue. It would be nice to have good BCs built w/o the design constraints for those who consider integration superfluous.

 

[halocline]

She's going to be much happier with a backplate if she's looking for stability. There are work-arounds for the pockets. I clipped a dive rite mesh pocket to the bottom of my plate, it kind rides on my butt, for my SMB and spool. She could try something like that; thigh pockets are another good option; and there are lots of small pockets available that thread on the waist belt. What exactly does she want to put in the pockets? You might start with that question and then figure out how to stow those items.

If she's dead set against the plate, she could try a transpac; I've never used one but have heard pretty good reports about it's stability.

Most jacket (or back inflate) BCs that have two tank straps do not have a hard plate, at least the ones that I've seen.

 

[Dive Rite]

Can anyone suggest a back inflation or other BC that would do a better job of immobilizing these tanks? She's tall and wears a Men's medium - women's BCs are too short in the waist. I think she'd prefer non-integrated - the tank alone is heavy enough, but I gather integrated is how they're built.

Hi Spoolin01,

A TransPac or Transplate might be a good option for your wife, they can both handle heavy single tanks as well as double tanks. This type of set up will allow your wife to customize the harness so that it fits her body shape. Both the TransPac and Transplate allow you to accessorize with pockets of your choice. You have the option of adding 16lb or 32lb weight pockets and also a range of pockets to store equipment in. You can check out the TransPac here:
SCUBA Diving Equipment for Technical, Wreck and Cave Diving: Dive Rite, Inc - Product Catalog - TransPac® Harness

Also check out the Solution Finder on our site, the question "Is a jacket or harness BC right for me?" might give you some ideas on what to look for when choosing a BC and the advantages of some of the features of the harness system.
SCUBA Diving Equipment for Technical, Wreck and Cave Diving: Dive Rite, Inc - Solution Finder

If you have any questions don't hesitate to contact us.

Best,
Ag

 

[Scuba Ken]

Buoyancy switches a lot when you go from Aluminum to Steel. In particular, it may make you want to turn turtle, which is what happens to me. The heavier tank wants to go down while wetsuit clad buoyant me want to go up. This can make you feel that tight rope feeling as you battle the tank for control. So far the only solution that works for me is to move all my weights towards my belly button as much as possible.

Basically the more buoyant aluminum tank wants to pull up while the heavier steel likes to pull down. If you don't have enough weight low on your center of gravity the constant battle to see which is on top in really annoying.

Ask her if the issue gets better as the dive goes along when the tank gets lighter. That would be a tell tail sign. If she has some of her weight on her back under the tank this would make the effect even worse.

I use a transpac btw and it locks the the cylinders to you if its just a wobbly cylinder that is bothering her.

 

[RPanick]

It sounds like the Jacket BC possibly with the combination of the position of the weight belt might be the problem. The jacket BC will tend to be positive, lower on the body, the tank negative on the high side. Roll a bit and you get BC wanting to go up on one side, tank going down on the other side. If the weights are towards the back that would just agrevate the problem.

On the surface the problem is even worse, the tank, BC and wet suit are all working together to roll her on her back.

Moving as much weight towards her stomach will help, at minimal cost. If that doesn't work, then you are probably looking at another BC/BP.

Two options, obviously the BP, and you can get pockets to put on the belt, one of the guys I dive with has weights and a pocket on his straps. Granted they are small pockets.

A BC like a Zeagle with back inflate and integrated pockets might be easier. My Ranger and Concept II will both take quite a bit of weight and compensate for my steel 100 very nicely. On the surface, the balance works really well. It also has pockets.

In both cases back inflate helps to stabilize with a negative tank, both when swimming and when up right on the surface.

One consideration, if your wife doesn't like playing with her gear to get it adjusted just right, then consider going with straps with adjustments or a BC. All the BCs I've dealt with are very easy to adjust. My wife doesn't want to mess with adjusting straps and all that, put it on snug it up and into the water.

On the two tank straps vs one strap. I think someone mentioned that two strap setups like the Zeagle do it because the back is soft, and without two straps the tank would tend to move about. Good part of two straps is you are much less likely to have your tank slip. Bad side is that two strap BCs don't always work well on boats, and its a little extra work to switch out tanks.

 

[marchand]

My suggestion would be for her to get a SS back plate and a wing, the BP will hold the tank solidly while allowing her to remove some weight off her belt. As far as pockets go, glue some to the dry suit.

 

[spoolin01]

Thanks to you all for the knowledgeable input. I found a back-inflate Oceanic Chute II for a good price, and based on one two tank day, it seems to be a success. She moved her ~20lb of soft weights to the dump pockets, and between that and the flotation located between her and the tank, neither horizontal nor vertical stability were an issue. The BC has a well-shaped channel for the tank in the hardpack and there was no problem with yaw. I'm not a fan of weight integration, but it's easy to insert the pouches after the BC is donned in the boat, so the inconvenience of the massive BC weight is minimized. Next stop: backplate and wing!