Problems at surface with sidemount rig

[pisoiu]

Hi all,
I need a bit of advice regarding my sidemount configuration. I am using a dive rite transpac mounted over a dual bladder super wing. The wing is a bit modified, I tightened as much as possible the bungee which is routed through the wing, restricting it to fully inflate at its original full lift. I don't need that much anyway. By my guess, when I fully inflate it now, the lift is around half compared with original full lift. Normally I do not have issues with this configuration, I usually dive solo in our local quarries where entry/exit is very easy and I do not need to surface in the middle of the lake. Under water, trim looks fine to me and I do not have other problems. However, last dive in our local quarry was not solo and I was in a group of 3 divers. Me with sidemount, other 2 with standard rec. configuration. One of them did not paid too much attention to the bottom and soon enough they stirred up everything and 0 visibility was there in seconds. Because of this, we separated quite often and we needed to surface. And here started my problems. I was unable to keep a confortable position at the surface, regardless of how much the wing was inflated. I had to fin quite strong in order to be able to maintain a position in which I could take out my reg and say 2-3 words. The rig was strongly pushing me with head in the water. I was in dry suit with 200 undergarment, tanks were 2x8.5 liter steel (eurocylinder) and 6kg of weigth mounted on the back of my transpac, in the lombar area. Those 6kg were a bit too much, I could do it with 4kg as well.
So, please tell me what can I do to improve surface comfort? I must add that I do not have formal sidemount training, there is no instructor for that in a 500 km radius.
Thanks.

 

[nakatomi]

I was in dry suit with 200 undergarment, tanks were 2x8.5 liter steel (eurocylinder) and 6kg of weigth mounted on the back of my transpac, in the lombar area. Those 6kg were a bit too much, I could do it with 4kg as well

Can you maybe take a picture of your rig with the bladder being inflated and the positioning of the weights visible?

I use the Transpac too, with the Nomad XT wing as a bladder and the same ECS 8.5l tanks as you. However my weights (8Kg with the 400g undersuit) are positioned in the Nomad weight plate on the back of the transpac.

A picture of your rig may help locate the root cause of the issue.

 

[decompression]

I see, my first impression is that you are overweighted for the lift of the wing. Has this happened only once? Secondly, I suspect your modified wing could be a big issue. Also, the way the tanks are rigged could contribute to poor surface stability. I do understand that there is no instructor near you, maybe continue researching side mount and specifically the drawbacks of using a BM wing as well as a double bladder. If you can, post photos of your rig and tank rigging.


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[pisoiu]

It also happened some time before during my tests and tweak sessions at pool but it was not noticeable because I did not need to surface elsewhere than entry/exit point.
I will take some pics asap and post them here.

 

[tbone1004]

yeah, go that route with pics. Sidemount isn't quite as easy as doubles to hang out on the surface, but with my Nomad it's not bad at all.

 

[pisoiu]

Ok, so, here they are.
The wing is fully inflated in the last pic. A 2kg weight is also visible there, beneath the water pouch. Above it, not visible, is another one identical.
I'd say the whole rig is a bit lower on the pictures due to gravity pull, between 5-10 cm. Usually, when in the water, I adjust it a bit and pull it upwards.

 

[tbone1004]

here's where I'd start. You're likely having trim issues with the big weights that low on your back, move them up.

Change the bungees that you are using to retain the wing to 2" webbing or 3" suspender type elastic material *similar to what dive rite uses on their hose retainers. This will better distribute the air in the wing. You may also want to consider sewing in retaining tabs that can be attached to the waist strap as that will work much better at holding the wing down. Should be really easy to hand sew into the cover. The bungee you are using right now is very strong, much stronger than the springs in the OPV's, so the 2" webbing or wider elastic will help to bring back some of the lift you are losing as well as not trap air as bad.

Lots of other things in the pictures that we could critique, but the above is just an address of the surface issues. Biggest thing is it sounds like you don't have enough lift in the wing which is why you have to kick. Regardless of the actual trim of the weights, if the rig can support you at the surface, you have enough lift and just need to learn to position your body properly, mainly leaning back like you're in a reclining office chair. If it doesn't have enough lift, nothing will fix it.

Also consider closing your drysuit dump valve so you can use the suit for some lift at the surface.

 

[pisoiu]

I'd say I have enough lift. At the surface, the wing is nowhere near full. I can feel how much is inflated by sensing how much is pressing on my back. If I stop kicking and relax completely, I have no trouble staying on the surface. It's just that I'm with my face in the water in a near horizontal position. I also tried to lean on my back, but no luck there either. Maybe I did not tried hard enough..

 

[decompression]

Firstly, I commend you on your efforts thus far with out an instructor.
And very good pictures.

The first issue I see, even with gravity the tanks are way too low. They should be nearer to the arm pit when in water. So try to move the neck bolt snap to the upper Dring and then possibly move the Dring up as well.

With the tanks so low and all your lead buy your butt you'll be severely leg heavy.

The lower tank band should be lower as well.

As far as lift/buoyancy goes, it looks as though that wing should have no problem lifting all the weight. Getting your face out of the water though could be tough as it looks like 80% of your weight is below the waist belt.

You've got lots going on there (inflators, light heads, batteries, knives etc) that are affected in their placement by the BCD itself.

If you want to continue with this rig it's gonna take lots of time to sort out.

Firstly, get the tanks rigged and connected correctly.
Relocate your weight to make you far less leg heavy.
Once that's complete and you are skilled at maneuvering under water and handling your tanks.

Then start placing your accessories so that they are accessible and don't interfere with operation of the wing and handling of the tanks.

Let us know how it goes and if there are any more questions. Best of luck!


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[tbone1004]

move the weights higher up on your back, and if you have enough lift, then just lean back.

One of the things you should consider is going to loop bungees. Part of the problem may be the cylinders being too loose and pulling you forward. If they were captured by the bungees then you shouldn't have a problem.

Cave Adventurers - Cave Adventurers Old School Kit for Nomad - Marianna, Florida USA - Never Undersold!
That would fix it. If importing is too prohibitive, you can obviously DIY with some webbing, 5 SS grommets, and some bungee. Will do two things for you, will help keep the wing in the right spot, and will pull the tank valves back where they are supposed to be.