Doubles

[Razorblade]

I am just curious:
Is it best to have a setup of two heavy tanks (i.e: neutrally buoyant) or two light (i.e: normal) tanks when diving with doubles?

 

[rmediver2002]

The military is still using double AL 80's for most working dives, the problem is not noticable at the begining of a dive. (you end up going in heavily weighted) but at the end when the majority of the air is consumed and the tanks lighten up.

I would go with steels not because they are heavier but because they remain at a more constant weight throughout the dive...

Jeff Lane

 

[omar]

The weight of tanks does not change through out a dive and the buoyancy will also not change based on what kind of tank is used. The change in buoyancy is related to the amount of gas that is used. 100 cubic feet of air (or 160 or whatever) will weigh the same no matter what kind of tank it is in.

Initially you will need to compensate with more weight on the belt or other places for a more buoyant tank such as Al80’s compared to steel tanks. But, once that is done the change in buoyancy will be the same if it is in steel tanks or aluminum tanks.

omar

 

[Northeastwrecks]

Razorblade once bubbled...
I am just curious:
Is it best to have a setup of two heavy tanks (i.e: neutrally buoyant) or two light (i.e: normal) tanks when diving with doubles?

The answer is dependent upon they type of exposure protection you are using (dry or wet), the requirements of the dive (time, depth and required amount of gas) and, to a lesser extent, the equipment being used by your buddies.

If you could provide us with that information, it would be easier to respond.

 

[Razorblade]

I guess that's the answer: there's no definite answer; just depends on your equipment for that dive.
I know that the difference in weight is only due to the amount of air consumed during the dive, but the empty weight of the tank will determine how many lbs. of weight you need to add to remain neutral at the end of the dive. By "Neutrally Buoyant" I was talking about Luxfer's AL80's that have a +0.05 lb buoyancy when empty, I didn't mean that the difference in buoyancy throughout the dive was zero.
Just so y'all get a better feeling of where I'm going with my question here's a little background: I'm an advanced open water diver and have decided to finish all of the recreational diving and then continue onto tech diving. I was just curious if I should purchase two heavier tanks so as to not have to put on more weight intially or would the weight of the rest of the equipment be so great that using heavy tanks would just make me have to put more air in my BC......but I guess I should get heavy and light tanks so I can adapt to every dive's equipment. Is that correct?

Thanks for taking the time to answer my question.

Razorblade

 

[Richeod]

I would hold off buying my own tanks at this stage of the game. With VIP's, hydros, O2 service and the price of fills it will most likely be easier and cheaper to just rent tanks. Most shops rent standard AL80's which is probably the best tank for you anyways.
If you still want to buy your own I would recommend you get AL80's (not the neutral ones). They hold plenty of gas for recreational diving and when you move to tech diving you can double them. It is far easier to add weight than to take it off. If you get steel tanks or even neutral aluminum ones you can easily find yourself overweighted, making balancing your rig impossible. Your only option is to then add air to your bladder which introduces a whole new batch of problems.

No need to get both tanks to "adapt". Use the ones that best fit the dive you are doing. Don't change your dive habits in order to make the gear you have work. Buy the right gear and no adapting is necessary.

 

[Razorblade]

I already got a tank (a neutral one). The reason I got that kind is because I figured that way I would have to add less weight when wearing a wetsuit. Since I don't usually dive without one I didn't really worry about the extra air I would have to add to my BC when diving only in shorts.
That's the reason why I asked what is best when diving with doubles so as to know if to buy only one more neutral tank or two more lighter ones and keep the one I have now.
The reason I decided to buy my own tanks is because I dive quite frequently and realized that in a very short time I would pay off the price of the tank. I am about to buy some more since there's not much I can do with just one tank so I always have to rent extras.

 

[Razorblade]

The only difference between using aluminum and steel doubles is that steel ones require you to put less additional weight on?

 

[Dryglove]

Razorblade once bubbled...
The only difference between using aluminum and steel doubles is that steel ones require you to put less additional weight on?

Yep

 

[Kangy]

However if your diving wet especially with a thin suite, with large steels then you would have too much weight, which is just as bad if not worse than not having enough weight with Aluminum and compensating for it