Negatively buoyant and deciding on tanks

[smokn']

Do you have a steel backplate?

Oh, and I have an aluminum backplate.

 

[elan]

I do have exposure protection, 5 mil all around (suit, gloves, hood, and boots). Unfortunately, I haven't had sufficient time to dial in my buoyancy with all of it on yet. I have been using 6 lbs with an 80 in fresh and saltwater when I'm wearing all of my exposure protection, but it seems like a bit much.

It looks like you need to do a proper check. It cannot require tge same amount in both fresh and salt. I put 6 more pounds for salt with my single rig.

 

[smokn']

It looks like you need to do a proper check. It cannot require tge same amount in both fresh and salt. I put 6 more pounds for salt with my single rig.

I completely agree, I unfortunately haven't got to it done yet. When I finished OW, my instructor had me using 14 lbs with no exposure suit and I've been parring it down since then, just haven't got it completely dialed in under different circumstances yet.

Maybe asking tank advice at this point was a bit premature, but I figured I would get some ideas going anyway.

 

[joel smith]

Hello smokn , you should give diveprof a shout. He has recently retired and was going to give my mother in law private lessons to help get her up to par on her bouyantcy it would probably take only one class. When he taught me my AOW that was the first thing we did , in just one class it was amazing the difference was like day and night.

 

[smokn']

Hello smokn , you should give diveprof a shout. He has recently retired and was going to give my mother in law private lessons to help get her up to par on her bouyantcy it would probably take only one class. When he taught me my AOW that was the first thing we did , in just one class it was amazing the difference was like day and night.

Hmm, I might do that.

 

[Bubbletrubble]

YASWQTCBAWAPWC.
(Yet another Scubaboard weighting question that could be answered with a proper weight check.)

A "new" weight check is required whenever the gear configuration is changed. In particular, a diver should do a weight check when the following gear/condition changes: exposure protection (wetsuit, hood, hooded vest, drysuit, drysuit undergarments), BC, tank, fins, extended hiatus from diving, fresh to saltwater or salt to fresh water. Bear in mind that the lead weights that a diver finds on a dive boat or at a dive destination might not be labeled correctly.

With regard to tanks...
The Techdiving Limited tank specs chart lists the buoyancy specs for many different tanks. Theoretically, a properly weighted diver using a tank listed in the chart can calculate his new weight requirements if: (1) the only thing changing is the tank and (2) the new tank is listed on the chart.
For a diver interested in proper weighting, the key piece of info in the chart is the buoyancy spec for the empty tank.
For example, a diver interested in moving from a Catalina S80 (+4 lbs. empty) to a Worthington X7-100 (-2.5 lbs. empty) could remove 6-7 lbs. of lead.

With regard to moving from fresh to saltwater...
The density of saltwater is greater than the density of fresh water. Consequently, all other things being equal, the same diver + gear configuration will be more buoyant in saltwater. Q: How much extra lead weight will the diver need in saltwater? A: About 2.5% of the total weight of diver + all of his gear. For average-sized individuals, this works out to about 6-7 lbs.

The above are just theoretical calculations. They should not be used as a substitute for a proper weight check.

In my opinion, newer divers fresh out of OW class should be doing weight checks at the beginning and end of every dive. If you are doing a weight check with a full tank, simply compensate for the weight of the gas in the tank while doing the weight check. For instance, a diver could determine proper weighting with a full AL80 tank and then simply add about 6 lbs. (which represents the change in tank buoyancy from full -1.8 lbs. to empty +4 lbs.).

The OP mentioned that he prefers to dive without a wetsuit when diving in Florida. Unless the water is 98.6°F, he will be losing body heat while in the water. It may not make much difference when he's kicking 100% of the time and the dives are very short -- 2 hallmarks of a novice diver -- but as his skill improves, he'll be hovering more and his in-water time will increase. That's when he'll discover the value of wearing adequate exposure protection and he'll be happy to adjust the amount of air in his BC to accommodate for compression of the neoprene at depth. There's also the protection that a wetsuit affords from stinging marine critters and sharp rocks.

 

[aquaregia]

I do have exposure protection, 5 mil all around (suit, gloves, hood, and boots). Unfortunately, I haven't had sufficient time to dial in my buoyancy with all of it on yet. I have been using 6 lbs with an 80 in fresh and saltwater when I'm wearing all of my exposure protection, but it seems like a bit much.

I use about 6# with a 7mm and a steel backplate. I'd say 6# with 5mm and aluminium isn't unreasonable.

 

[elan]

I completely agree, I unfortunately haven't got to it done yet. When I finished OW, my instructor had me using 14 lbs with no exposure suit and I've been parring it down since then, just haven't got it completely dialed in under different circumstances yet.

Maybe asking tank advice at this point was a bit premature, but I figured I would get some ideas going anyway.

You see before you make the right decision or anybody can help you to make it you need to get the correct input data. Otherwise it's just speculation. We can talk a lot about what can be done but it might make no sense at the end.

Just get your data and then it will be like a piece of cake.

 

[smokn']

You see before you make the right decision or anybody can help you to make it you need to get the correct input data. Otherwise it's just speculation. We can talk a lot about what can be done but it might make no sense at the end.

Just get your data and then it will be like a piece of cake.

Gotcha, well like I mentioned, I'll be heading to Fl soon so I'll try to take special notice of my weighting while I'm there and get things figured out. Thanks everyone for your guidance.