Doubles? how soon?

[PerroneFord]

Not required for donkin around in a pool. Heck, a lot of "tech" divers can't even do valve drills.

Isn't that the truth.

 

[JeffG]

Isn't that the truth.

Scary, but true. Some even teach the stuff.

 

[*Floater*]

Like I somewhat mentioned... I'm not ready for the type of diving that REQUIRES doubles. But my thought process is: If spend energy and time getting my trim and weighting and adjustments down, why not only do it once ( in doubles). This would give me the time to learn to dive in doubles before taking more advanced classes. I wouldn't want to invest money into training to learn something and instead be a bumbling idiot because i've never dove doubles before. I have some pretty good mentors and plan on asking them their opinion as well because they have seen me dive.

Thanks for your thoughts

Go for it. But while you are at it, throw in a long (7 ft) and short hoses and a cannister light. Then practice valve drills and air sharing during your pool session. One thing that I'm still learning is what exactly to do with the light during various scenarios: when to stow it? how to stow it? draping it over you neck? perhaps thumbing the light if you have a goodman handle? ... also practice clipping it on and off (wthout trapping the long hose)... practice clipping everything on and off... what do you do with it during various drills (valves, air share, mask on/off)? what about when writing in your wetnotes or doing reel work (in the dark) or shooting a bag? also make sure you can clip your hung bottle on and off with your eyes closed because you may not always have light to do it (and you should need light to do it)... in fact, make sure you can clip everything on and off with your eyes closed... you could even buy some of the 5thd-x DVD's and try all those skills out.

anyway, doing the above skills isn't supposed to be difficult, but just make sure you can do it with very good buoyancy and trim in one spot while keeping track of your buddies. oh, and practice hoovering motioneless without moving your fins... people often kick up silt when they "stop".

edit: i wanted to add that it's NOT recommended to practice valve drills solo because somehow people often manage to turn all of them off, and you never want to make that rapid ascent to the surface...

 

[Mo2vation]

Diving twins is essentially the same as diving a single tank, except the weight is better balanced. If anything, twins are slightly easier.

Cert in 99. about 650 dives. Thought I'd give them a whirl last month. After about five weeks (and 30-some dives) in all manner and size of doubles, my topline observations:

Moving them around topside is an issue. But if you're smart and remember they're, you know, HEAVY, ain't no thing. I got used to it. But they're a schlep.

Many shops have no clue. Always, always check your pressure and be sure your isolator is open when you pick them up. And double check them again... I had some interesting fill experiences...

Harness fit matters more in doubles. I run with a loose harness for my singles (loose my most objective measurements...) because my single wing is empty most of the time underwater. No can do with doubles, as the wing nearly always has gas in it. I cinched the thing down, and it made a huge difference.

Breathing impacts buoyancy less. read: you don't move as much or as effortlessly by simply controlling your lung volume. This was an important thing to learn as a photographer, as my hands are usually busy. I needed to think ahead and just change things a bit. After a dozen dives, I was in the groove.

They start slower. They stop slower. They turn slower. BUT, they are solid. Rock solid. Loved them. You wanna pin a stop, doubles are great. Excellent shooting platform - I liked shooting in them. Back kick is cool, too. Because of the mass, all you gotta do is get them moving... if you're back kick is mediocre (like mine is), in doubles, I looked great! Get 'em moving, and you're a back kicking fiend.

Surf entries rock. I get tossed about much less going through the surf in 95's than I do in my 130. Exits... that another story.

I'm DIR - and its very clear that everything DIR (hose length, hose routing, hose deployment, gear configuration, protocol, etc.) was built for and around doubles. In them, everything was easier. A LOT easier. Valve drills, checking my SPG, OOA drills... everything I learned on a single tank became much easier with Twins.


One of the most important things I learned was this is mad gas. I mean, just stupid amounts of gas for my SAC and the diving I do (recreational diving 130 and above... generally 110 and above.) It'd be easy to get into trouble with all this gas. Doubles illuminated the need for additional training for me so I can plan these dives better.

I loved them. I mean crazy-go-nuts loved them. I can't wait to select, schedule and get into my classes so I can go see some more stuff. I can see how some people, once they dive Twins, never go back to singles. They behave differently underwater, but for me, they were much more friendly than diving a single. Diving them is a skill I'm glad I took the time to learn.

I'll be coming back to them soon.


---
Ken

 

[PerroneFord]

I practiced the darn thing in the pool, but was never really "good" at it. When my backup reg o-ring blew in Jackson Blue (about 400ft back) I was surprised at how I went onto autopilot. Seemed like nothing. And of course I had to get through both the right post AND the isolator, and then discover the issue. I couldn't see it in the cave and it was too small a leak to feel against my face. But you could really hear it.

I'd be kinda nervous diving with someone in doubles who couldn't shut their posts down. Part of that gas is MINE!

 

[rongoodman]

Not required for donkin around in a pool. Heck, a lot of "tech" divers can't even do valve drills.

I can't agree with this. The main advantage of the doubles is the redundancy they provide. If you can't use the valves to isolate problems, you might as well just buy a bigger single tank and save some money.

 

[JeffG]

I can't agree with this.

Then don't, but it doesn't change the truth. You don't need to manipulate your valves underwater to play around in a pool. Heck, its a place to learn those skills.

 

[jtivat]

Not required for donkin around in a pool. Heck, a lot of "tech" divers can't even do valve drills.

I was shocked to learn this, there are four of us taking Normoxic Trimix and the first skill we did in the lake was a valve drill. When we all four did them in less than the required time on the first try the instructor was surprised and mentioned this was the first time he had a group of four all do it on the first try. This shocked me, how do you get to Trimix class with out being proficient at a simple valve drill? It also seems weird to me when I hear people say they practice them on every dive, this is not rocket science if fact I would say it is very easy but maybe I an weird.

 

[JeffG]

I was shocked to learn this, there are four of us taking Normoxic Trimix and the first skill we did in the lake was a valve drill. When we all four did them in less than the required time on the first try the instructor was surprised and mentioned this was the first time he had a group of four all do it on the first try. This shocked me, how do you get to Trimix class with out being proficient at a simple valve drill? It also seems weird to me when I hear people say they practice them on every dive, this is not rocket science if fact I would say it is very easy but maybe I an weird.

Well, I know of one TDI Deco Procedure instructor that can only do valve drills in the pool with his 3mm suit on (and when he did it...he turned all his gas off <snicker>)

When he tried it in his Fundi's class, he was bouncing off the bottom for about 5-6 mins before giving up.

and no...I'm not making this up.

 

[mattroz]

well i don't want to be like that... any tips.. or links to the proper way of doing it (order?)