Weighting for self-rescue.

[ginge]

Hello all.

I have been diving on and off (as finance allowed) for 15 years or so, starting with BSAC and going the PADI route on holiday in 2001.
Since then I have done a lot of dives on holiday (warm water, good vis, no exposure protection).

I approached diving as I do everything - methodically. I like doing things right (but not necessarily Doing It Right).
As such I always did a couple of review and skill refresher dives in the UK before going abroad and focus on skills while diving.

One of those skills was the complete removal and replacement of my equipment underwater to facilitate self rescue on becoming entangled where you cannot reach.
I was originally taught it by my university BSAC club in the 90s and I don't know if it is still taught.

Recently I have decided to take my diving more seriously and (since I have the funds) do more UK diving.

I have done the dry suit speciality and have been trying valiantly to get back my previously good buoyancy control with the suit on.

I have also been won over by the idea of self reliance, in truth I have dived solo more times than I can count if one doesn't include incompetent or dangerous buddies.
I am off to Mexico next month (with my life-long buddy, no insta-buddies this time) and on my return I am going to get some equipment together and focus on getting the SDI solo certification.


I already have a lot of it and I am strongly leaning towards independent back mounted twins for my breathing gas.
My idea is to have three cylinders (two on my back, one on the shore/in the boat). Breathe one down a third (leaving two thirds in it) breathe the other down two thirds and surface. Switch the mostly empty one round for a full one and then reverse the process on dive 2.


My question is about weighting though.

Currently I have a BP/W with integrated weights which I cannot remove underwater without doing an impression of a Polaris missile due to the buoyancy of the drysuit.

I have tried dumping all the air out of my drysuit to the point of squeeze but I still have +ve buoyancy.
I can't wear a weight belt due to not having a waist .

I am considering wearing a harness with just enough weight to keep me neutral in a mostly empty drysuit and having the rest on the BP/W. I just don't like the complexity with all the extra pinch clips and straps.
Ideally I would like to be able to shrug out of my harness have me and it both be neutral just like I have done dozens of times without the drysuit.


What would you do/do you do?

Any brilliant ideas I haven't thought about/seen?

 

[DevonDiver]

Why not consider sidemount? That ticks all the boxes - same principles as indie-twins, very easy for travel/holiday and you only wear the harness.

I use a Razor-type harness weighted to keep me neutral. Then I only have to add weights to the cylinder bands to cope with cylinder buoyancy (if using/renting ali tanks).

For self-rescue... well, you can partially or fully remove one or both tanks. The harness can stay on.

If you want to stick with BP/W, then many divers find it acceptable to fit a larger proportion of their weighting directly into the rig (non-dumpable). Steel backplate, weighted STA (for singles), 'V-weights (for doubles) or even regular weights added to the harness webbing (top of shoulders can help trim). Do a Google search for the term "balanced rig". You need enough dumpable weight/ballast to enable positive buoyancy - that doesn't mean all your weight has to be dumpable.

 

[gekodivebali]

Sidemounting would be a solution indeed. I do what you describe with tank switching a lot, with or without deco gas on top of the 2 backgas tanks. Tanks can be ditched if needed. Probably easier and more logical than indie backmount...

 

[ginge]

Hmmm.

What I was thinking is that if I were to get further training I could take the back mounted indie twins and a single sidemount of bottom gas.

I have thought about side mount and although it appeals it looks "messy" and going to more than 2 cylinders looks even more so (messy is my best approximation to what I feel).
I know it is not strictly a safety/risk management issue but whenever I am able to personalise kit (army, mountain biking etc.) I find that if it looks right and feels right then I am comfortable.

I associate comfort with low stress levels, low task loading and better safety.


It could be that the very few guys I have seen at my local sites who sidemount are just messy divers. I like everything to be in its place. My regular buddy looks like a slow-motion explosion under water, lots of things on lanyards hanging off him.
I can't stand it.
I think I'll have a search for pictures of squared-away sidemount divers.

If I throw in some perceived pros and cons can the sidemount soloists let me know if they are valid please?

Sidemount pros:
Easy travel.
Easy submerged kit removal and replacement.
Cylinder valves visible and accessible.
Very easy to hand off cylinders back into a rhib.

Sidemount cons
No tidy way (that I know of) to route dry suit and BCD inflater hoses*.
Possible irritation from tanks moving, especially if I invert or swim on my back - I don't know.
Trickier to enter water (at least the guys at my local make it look so).


* as a thought do you think there is enough gas in a little suit inflation bottle to do the BCD too? Keep that on your body and have just the breathing gas on sidemount?
Perhaps a slightly larger cylinder like one of the skinny 100mm by 300mm 3l ones off a rebreather? Can't travel with that though.


I don't know, this has just opened a whole can of worms for me.
I've a lot to think about.

 

[Crass3000]

Deleted due to solution already being mentioned.

 

[lowviz]

...//... My question is about weighting though.
...//... Any [-]brilliant[/-] ideas I haven't thought about/seen?

First, you need to determine your true "at depth" buoyancy in mask, fins, all your undergarments, and your drysuit. "Some" have managed to do this in a pool with a shop vac exhausting the suit. Close valve. Yes, it is uncomfortable. Pick up lead weights 'mix and match' with a half a lungful of air until you are neutral. You are holding the first answer...

Next weigh your BP/W, regs, cylinders at 500 psi (35 bar), and associated gear under water with wings totally deflated, you can use a fish scale. This will be a negative number.

So if the difference between the two values is a positive number, you are buoyant and need to add said value in lead somewhere on you. I suggest putting 6-8# (3-4 kg) as ditchable weights ON YOU and the rest secured on your rig (V-weight etc.)

 

[w ripley]

. . If you want to stick with BP/W, then many divers find it acceptable to fit a larger proportion of their weighting directly into the rig (non-dumpable). Steel backplate, weighted STA (for singles), 'V-weights (for doubles) or even regular weights added to the harness webbing (top of shoulders can help trim). Do a Google search for the term "balanced rig". . .

That pretty much sums it up for BM.

If you go BM, you're talking about going to a wing (sorry, I can't figure out if you're using one now or not). Unless you are diving with a helium mix, which will make your drysuit cold, you can inflate both your drysuit & wing off of your BM tanks, so you don't need the extra hassle and weight of a drysuit bottle, its reg & hose. And you don't use that much air to run both, even on very long dives.

Unless you are going very deep, and have a ton of deco tanks, you're really not talking about ditching any weight. Actually, the goal is to get as much weight off of your rig as you can and still be able to go under the water. You add weight to your BP for salt water and remove it for fresh. Remember, dumping weight may sound reasonable, but you still need to be able to recover from an uncontrolled assent. We all have moments when we find ourselves shooting upwards and have learned how to manage our buoyancy recovery.

You will come to master your drysuit, and that means keeping the OPV on the arm open at all times and just adding enough air to take "some" of the squeeze off. Don't get into the habit of diving with leg weights, etc., as you will just have to "unlearn" diving with them down the road. Once you get there your drysuit will be your best friend. It will also be your emergency lift should you lose your wings.

I dove a BP with wings & doubles for many years before going to a rebreather, which has basically the same configuration. Like everything else in diving, you just have to dive to get comfortable with your gear.

I have no experience with SM, although it seems to be the way a lot of tech diving is going. I, too, have difficulty with the SM gear configuration when carrying many extra stage or deco bottles (or bailout bottles), but those diving SM seem to make it work for them. Suggest you at least try it before you go one way or the other.

Good luck.

 

[Johanan]

Ginge,

Hihgly likely that you have seen messy sidemount divers. Check out Steve Bogaerts video galleries, esp. #9, 14, 15. If you are off to Mexico, why don't you take a course with him? Devon Diver's videos can be salutary, too. Actually, a good sidemount course could make you a better solo diver than the SDI solo course, IMHO. Regarding sidemount and dry suit try to ask Garry Dallas on his Facebook account or from his website. You seem to reside in UK, heading to Mexico - so you have an easy access to some of the best sidemount instructors on the planet. You even have funds! I really envy you.

 

[DevonDiver]

...whenever I am able to personalise kit (army, mountain biking etc.) I find that if it looks right and feels right then I am comfortable.

Me too... ex-UK mil... my sidemount is personalized, clean and very non-cluttered. A properly experienced sidemount instructor will square you away in this respect.

Sidemount cons
No tidy way (that I know of) to route dry suit and BCD inflater hoses*.

That's just a case of selecting an appropriate length LPI hose for the model/design of sidemount BCD you use.



In my case (above) I have a 6" LPI hose routed from the bottom (5th) port on a SP MK25. This routes directly to the inflator that comes from the bottom/hip of the wing. It lies flush across my chest; non-impeding, easy to access and very streamlined.

Possible irritation from tanks moving, especially if I invert or swim on my back - I don't know.

I find it very 'free'. Yes, the tanks do move, but proper set-up means you feel so unencumbered that it remains a pleasure. I do inverted swims as part of my course/s.

Trickier to enter water (at least the guys at my local make it look so).

Proper Planning Prevents P*** Poor Performance

There's a range of options for water entry. A good course teaches those options. Common sense fulfills all other requirements.

If you need to walk with the tanks, or enter from a boat with tanks in place, use a 'choker' (solid additional attachment via cord/boltsnap). Otherwise, don your tanks in the water - there's a variety of solutions for that.

 

[dumpsterDiver]

Get a rubber weightbelt that WILL fit you; even if you have no waist...