Kit Selection and my reasoning

[schford]

I finally decided to take a walk(or is that dive) into more technical diving after three hundred or so recreational dives over the last 4 years or so.

I have spent the last month or so reading up on the board and talking to various very very experienced divers at my local dive centre in sunny*coughs* England.

I have always thought that one should make their own informed descions with regards to kit and hope I have done that. So please no flames saying its not DIR so its a suicide trap - a reasoned discussion how ever is valued as thats how we all learn.

Most of my diving in the UK is in coldish water and on wrecks - I wanted to be able to dive deeper for longer and have fully redundant kit, where I would feel comfortable making deco stops and not having a single point of failure.

Well obviously in this water a dry suit is in order and I selected one of these some time previously a Poseidon TNG Jet Stream, 5mm compressed neoprene, which is very warm and flexible. I prefer these to a membrane suit as I only need wear a very slim under diving suit and if the worst happens and it leaks at least I'll be warm.

For my regs I selected Poseidon Jetstreams (odin) key choice for me here is they are capable of supplying an excellent volume of air at depth with no problems and can be fed from the right or left. Also I am a fan of their timeless design and the fact that I have personal knowledge of serious techie divers who have never had a problem with them.

I have also made a necklace to go around my neck which holds both regs in clips which enables me to have both regs easily at hand (mouth!) to swap but also enables me to pull them off easily to hand off if needeed.

For my Bouyancy I looked at various combinations and dived a lot of these in my local lake - ranging from 'technical bcs' though to Backplates, harnesses and wings inc. most of the usual suspects.

I finally settled on a Northern Diver (a UK Manufacturer) Sea Eagle Wing - it is something of a hybrid system, a BC style harness (unecumbered around cheast, shoulders etc) with a stainless steel backplate and twin wings. Details at http://www.diveshop.co.uk/pages/accessories/buoyancy/sea_eagle2.html

I very much like the design and the way the twin wing is designed - it ensures that in the event of a puncture I still have plenty of lift - now I did consider having a single wing/bladder design and using my dry suit for redundant lift but with twin Steel 12.2ls and perhaps stage cylinders in the future I felt much more confortable knowing the lift would be on my back and not all around me. I am aware of the potential problems with twin wings - perhaps a slightly leaking valve which causes the redundant one to inflate but feel confident I can notice and cope with this and am also pleased with the location of the dump valves at the lower back where I can pull both dump valves imultaneiously to ensure that there is no air in the redundant wing when i trim the main wing.

I have also elected to dive fully independant cylinders (do I hear groans all ready! ;-) ). My reasoning for this is that I want a totally independant system - I am aware of the downsides - slightly increased task loading due to the neccessity of gas managment via reg swapping and the need for me to monitor 2 pressure guages. I feel confident in my ability to manage this and am happy to trade that slight downside against having a single point of failure.

I am aware that this perhaps might be viewed as foolish by some but believe it is a personal choice one must make.

One of our local technical divers who is very experienced had an incident a few months ago he was diving manifolded doubles and was about 50% into a dive he had consumed aprox 1/3rd[EDITED I had put 2/3rds down indavertantly] of his air when he had a problem - he was in a wreck and had knocked his left hand first stage on the wreck which caused a serious loss of air as he was unsure exactly what the problem was he closed the isolation valve, another diver who observed this estimated he took no more than 10 to 15 seconds to isolate the cylinders, however in this time his air was down to just over 40 bar(roughly 500 psi) which neccessated him 'borrowing' some of his buddies air to return to the surface. Now if he had not handled this in such a timely manner or his buddy had been out of sight then this story might well have had a very sad ending.

Where as if he was diving totaly independant cylinders(as he now does) he would have been left with 180 bar in the one cylinder that was left and not 40 bar.

I guess that illustrates why I choose to dive with totally independant cylinders.

My other choice that I have still to make is whether to have a 7 ft long hose, I am caught on this choice - I can very much see the benefits of it, however the configuration of it around the neck worries me for wreck penetration, the local experienced divers express some concern as to the possibilty of this getting caught and managing to strangle ones self - one of them however uses a long hose but attaches it next to his cylinder in a looped up manner to enable him to present it if needed.

Not sure how I will play this one other than trying it myself.

Well I have played in my local lake for a week or so now - so roll on the bank holiday weekend - off to Poole for 6 easy dives well inside my comfort zone in the ocean, here's hoping the kit configuration goes well!

 

[MikeFerrara]

With independant tanks you don't know which reg you'll be donating do you? Which tank would you put a long hose on?

Breathing a long hose routed around the body poses no entanglement or strangulation hazard.

Other methods of stowing a long hose can leqave you unable to re-stow it by yourself and IMO is much more likely to get snagged on something and deployed by accident. Keep in mind that many of the instances where gas might be donated in technical diving are temporary situations such. That leaves you in needing to restow the hose when your buddy is done with it.

I could see where helping some one out of a wreck without a long hose could be a problem.

What was your buddy doing still in the wreck with 2/3 of his gas gone? Also if he would have shut the post rather than the isolator firs I think he would have lost less gas. Failures that require isolation are less likely than those that require shutting down a post.

If I was compelled to dive alone I would use independants but I'm not.

 

[MechDiver]

Mike raised very good points. I would also question why you have both regs clipped off to a necklace? The secondary reg should be on a necklace, your primary should have a dogclip so it can be clipped off to a d-ring.

MD

 

[Wendy]

My other choice that I have still to make is whether to have a 7 ft long hose, I am caught on this choice - I can very much see the benefits of it, however the configuration of it around the neck worries me for wreck penetration, the local experienced divers express some concern as to the possibilty of this getting caught and managing to strangle ones self - one of them however uses a long hose but attaches it next to his cylinder in a looped up manner to enable him to present it if needed.

All I can say is if you are happy that is all that matters, cuz you are the only one that has to dive your kit. It doesn't really matter what we all think of it.

About the 7 foot hose strangling you, its not warp around the neck. its placed behind the back of the head. SO I don't see how managing to strangle oneself is possible. But make sure that whatever gear configuration you choose that you are trained to use it correctly.

 

[schford]

With independant tanks you don't know which reg you'll be donating do you? Which tank would you put a long hose on?

Breathing a long hose routed around the body poses no entanglement or strangulation hazard.

Other methods of stowing a long hose can leqave you unable to re-stow it by yourself and IMO is much more likely to get snagged on something and deployed by accident. Keep in mind that many of the instances where gas might be donated in technical diving are temporary situations such. That leaves you in needing to restow the hose when your buddy is done with it.

I could see where helping some one out of a wreck without a long hose could be a problem.

What was your buddy doing still in the wreck with 2/3 of his gas gone? Also if he would have shut the post rather than the isolator firs I think he would have lost less gas. Failures that require isolation are less likely than those that require shutting down a post.

If I was compelled to dive alone I would use independants but I'm not.

Thanks for the reasoned responce - its why I like this board - apologies it was an error on my part I meant he had consumed 1/3rd of his air.

Some good points on the long hose - my assumption was that I would just donate from which ver tank it was attached to - I very much see your point on restowing the hose - I think I need to consider trying a long hose for myself.

I agree if he has shut his post first he would have lost gas but his reaoning was that he did not know if he had hit the valve itself.

 

[schford]

Mike raised very good points. I would also question why you have both regs clipped off to a necklace? The secondary reg should be on a necklace, your primary should have a dogclip so it can be clipped off to a d-ring.

MD

Diving independants there is no secondary and primary - swapping is neccessatated due to gas managment - hence I want them both on a necklace in front of me - they are attached in such a way that thye can just be pulled off when a dontaiton is needed.

 

[MechDiver]

Diving independants there is no secondary and primary - swapping is neccessatated due to gas managment - hence I want them both on a necklace in front of me - they are attached in such a way that thye can just be pulled off when a dontaiton is needed.

Yea, my bad. My thinking, such as it is, is tuned to isolation manifolds and long hose.

MD

 

[wedivebc]

Diving independants there is no secondary and primary - swapping is neccessatated due to gas managment - hence I want them both on a necklace in front of me - they are attached in such a way that thye can just be pulled off when a dontaiton is needed.

I dive with my manifold closed (just like independant) . My long hose is on the right and I always start my dive breathing off my right hose. After consuming 1/3 of my right tank I switch to the left reg. I then breath another 1/3 from the left before turning the dive. My next third comes from the left tank (no reg exchange) after which I change to the right for the last 1/3. This leaves the most gas available to the long hose for the most amount of time.
I stuff the long hose alongside the right tank and both regs are bungeed around my neck. If I practice gas sharing it is at the end of the dive. Face it, any gas emergency will occur at the end of the dive since the dive is over when you have an emergency. I can then stow my hose around my neck if I need to. I know this is different than mainstream thinking but it has worked for me for years and I teach it to my students but also encourage them to make their own decision.
I don't believe you should do anything just because everyone else does.

cheers,

 

[WaterDawg]

Sounds like a Troll to me.

 

[schford]

All I can say is if you are happy that is all that matters, cuz you are the only one that has to dive your kit. It doesn't really matter what we all think of it.

About the 7 foot hose strangling you, its not warp around the neck. its placed behind the back of the head. SO I don't see how managing to strangle oneself is possible. But make sure that whatever gear configuration you choose that you are trained to use it correctly.

Thanks for the reply you are correct Wendy - I am the one to dive it, I believe I have thought the issues through but have read some good things on the board and always value a reasoned opinion.