My dive with doubles

[Narced Out]

Today was my first day diving with doubles. Basically my instructor help me set them up, showed me how to use the hoses and how they were positioned, and stuck me in the ocean.

I have never had so much fun before, being 16 and doing this is like a dream come true. My buoyancy was perfect, i was just tagging along with the advanced class trying these out. While the class was at 95 feet i was around 105 or so. Vis was good here in San Diego today. My deep diver class is in a few weeks, then i am a master diver!!!

My question is can my BC handle a set of doubles, if not what do i need to configure it to to make it possible. Concept II - Recreational BCs - BCs - Zeagle Dive Systems
This looks like mine. I have 2 aluminum 80s so i want to know if its possible to set them up with this bc.

 

[RTee]

When reading the description of the BC/Wing, I would tend to say that the answer is pretty straight forward...''...but does not plan to use twin tanks''. Zeagle makes a fair number of BC and BP with Wings designed specially to accommodate doubles.

I think you will also find several treads in SB discussing the pros and cons of attempting to use one single set-up for both single and double tanks configuration.

 

[Michael Kazma]

A bladder designed for a single tank cannot be used with doubles as it will not be wide enough. Also, a bladder designed for doubles cannot be used on a single tank.

It is fine to use the same harness and back plate with both but you must have different bladders for each.

In San Diego I recommend a bladder with at least 55lbs of lift for doubles.

Let me also ask you this: were the doubles set up as independent twins or as doubles? Also, did the instructor run though the isolation drills with you as these are essential to dive doubles?

 

[Narced Out]

Hey michael this is Jacob,

We did not run through isolation drills, he had his reasoning (i forget what he said). He had both valves open and manifold was open so i was breathing off both tanks. But i did fine for the hr long dive.

 

[AfterDark]

I dive independent doubles. I like the options they give me as well as the increased air capacity. I modified my BC to mount the doubles so I can go from single to doubles and back pretty quick. I can carry one tank at a time instead of carrying both. Some boats aren't setup to store doubles. I can store them as singles then put them together before the dive and back after. My safety factor is increased by having 2 separate air delivery systems. My unused regulator is my octopus. I don't need to reach my valves.

The down side is if a reg fails I can't use the air in that tank. With 2 regs on a manifold the use of both tanks is still possible.

 

[Sas]

Hey michael this is Jacob,

We did not run through isolation drills, he had his reasoning (i forget what he said). He had both valves open and manifold was open so i was breathing off both tanks. But i did fine for the hr long dive.

If you are diving with a manifolded twin set up you need to know how it works and be able to reach your valves. Get your instructor to show you next time as basically, if you don't know about this you were diving a big single tank, with no redundancy.

A bladder designed for a single tank cannot be used with doubles as it will not be wide enough. Also, a bladder designed for doubles cannot be used on a single tank.

Well this is not true. They can be used, but neither is ideal and in the case of twins with a single bladder, it may be dangerous.

In San Diego I recommend a bladder with at least 55lbs of lift for doubles.

What is your reasoning for this? I dive doubles and would find 55lb of lift excessive.

 

[TSandM]

I think it's pretty reasonable to do the first few dives in doubles, treating them as a big single tank. (Maybe that's because that's what I did ) Once you have adjusted to the trim and inertia differences, then you can start working on learning to close and open valves.

The wing size you need depends on the tanks you are using. If you are using double Al80's, I can't imagine you needing more than 40 lbs of lift. I dive 40 lbs in Puget Sound with steel 85s, and it's plenty. I had to go to a bigger wing when I used 95s in fresh water, with a deco bottle and stage, in my Florida cave class.

Glad you had fun, Narced Out. Just be really careful that you aren't rushing too fast -- you need to build experience and judgment, not just skills, to do longer and deeper dives.

 

[Sas]

I think it's pretty reasonable to do the first few dives in doubles, treating them as a big single tank. (Maybe that's because that's what I did ) Once you have adjusted to the trim and inertia differences, then you can start working on learning to close and open valves.

Sure thing, but I would think this better done on a dive that is not to 105ft for an hour.

 

[TSandM]

Yeah, I agree, Sas; I would never do a dive to 105 feet in totally unfamiliar gear. In fact, we have a great story here on SB (I think it's tstormdiver's) about someone who did just that with her first doubles dive, and got the stuffing scared out of her.

 

[gcs118]

Yeah, I agree, Sas; I would never do a dive to 105 feet in totally unfamiliar gear. In fact, we have a great story here on SB (I think it's tstormdiver's) about someone who did just that with her first doubles dive, and got the stuffing scared out of her.

Could you post the link for us?