Best guess, will I be too heavy with this tank?

[NorCalDM]

I'm 6' 0" and 185 lbs. With a 3mm wetsuit and my steel plate/aluminum cylinder and no added lead I'm a lawn dart in the pool now with my aluminum plate not to bad. Warm salt water with 3mm wetsuit aluminum plate and cylinder 0 - 4 lbs of added lead depending on witch 3mm suit I use old or new is all I need. Also I use a 30 lbs wing and it is more lift than I need in either situation.

 

[diverrex]

Unless you're diving overweighted, 25 lbs of lift is plenty for a single tank and 3mm wetsuit. Remember that it is a buoyancy compensator, and what it exists to compensate for is wetsuit compression and tank weight drop from breathing the air. I don't know your personal weighting requirements in your current gear but I know I'd be overweighted in a 3mm suit with a -7lb tank and -5.5lb backplate - even in salt water. This doesn't mean my 25lb wing is too small, it means my SS backplate is too heavy.

This is my situation also. I use a steel backplate for California diving in a dry suit or 7 mm but I purchased a Halcyon travel wing with a plastic plate for warm water 3 mm wetsuit diving and specifically diving in Jupiter, Florida where because of depths it’s common to use larger 100+ cu ft steel tanks versus 80 cu ft alu tanks. For typical Caribbean diving with a 3 mm wetsuit, my plastic plate and an alu tank I use 10 lbs weight. If I had a -5 lb SS plate now I’m down to 5 lbs. If I switched from alu to a -7 steel tank now I’m -2 lb and not wearing any weight. In Jupiter I can use a -7 steel tank and 4 lbs. If I had both the steel tank and SS plate I’d be overweighted.

 

[stuartv]

Before I switched to diving doubles, my normal config was 3mm wetsuit, SS BP, HP120 (steel), and 23# wing. Works fine for me.

Will you be too heavy? That depends on what you mean.

Is a 25# wing enough to get you neutral at depth? Almost certainly.

Is it enough to float your rig? Almost certainly.

Is it enough to get you positively buoyant at the surface? Very likely.

Is it going to be more weight than you need? I.e. will you be negatively buoyant with an empty wing and a nearly empty tank? Probably.

 

[Ayisha]

I'm pretty sure all the DIR types tend to eschew the use of steel tanks. Expect to see that in the responses. I'm not saying they're right or wrong but generally they seem to have a strong preference for AL from what I've seen.

It's larger steel doubles with a wetsuit that are more difficult to achieve a balanced rig.

 

[NAM001]

I dont know what the answer is to that question. I would say look at your current end result. As the tank affects buoyancy,,, find he worst mixture of gear normally used. wet suit etc. If you need a lot of lead then go steel. you have 3 main exchangable components that are in play. tank BPW and exposure suit

 

[Ayisha]

Great thoughts. Here are more details:

- Diving plans and profile: warm water and < 50ft, majority <30ft
- Dive Rite travel wing, 25 lbs
- Dive Rite SS backplate, 5.5 lbs (out of water)
- Dive Rite standard harness
- Regs: MK17/G260, R195 (these are not purchased yet, but likely)
- Diver: 6' 3", 175 lbs, nearly nuetral buoyancy
- No lights (for now)

I should also mention I am considering returning the 25 lb wing and getting a 30 lb wing. I know it's only 5 lbs more, but I don't plan to do any extreme diving so I don't need to look like an astronaut.

You might be ok with the HP steel 71 with your SS bp with your size, while with my petite size, I would be slightly overweighted. With my 1.8 lb AL bp, HP steel 80 and 3 mm wetsuit, I add 1 lb to each of 2 pockets on my cam bands, so a total of 2 lbs. So you would probably be fine with the steel 71 and SS bp.

I would be concerned though whether a 71 cf tank is enough to bring up both you and your buddy in case of an issue. An 80 cf tank doesn't sound like much more, but I would consider that instead.

25 - 30 lbs is quite standard lift for a single tank. I prefer 30 lbs lift personally.

 

[rsingler]

The answer to ALL of these questions lies here:
Buoyancy, Balanced Rigs, Failures and Ditching – a comprehensive tool
If you don't know the buoyancy of the components of your rig at the surface and at depth, you can't make an effective decision.
The spreadsheet is complex and needs some investment of time. But with its data, you can answer every question posed here. My 2¢.

 

[KenGordon]

I say "guess," because a proper weight check should be performed, but I need the guess for an initial purchase. Background: I only plan to do shallow warm water diving in the future. Despite that, I have a BP/W setup with stainless steel backplate, because I want to minimize lead on the waist. Now, I'm looking for a tank to use in the pool mostly, and I would like it to be light in mass (out of water) because I'm having some back trouble at the moment. I currently like this steel tank, but at -7 lbs full buoyancy (in salt), I'm worried I will be too heavy with only a 25 lb wing. Using the excel calculator that some folks use for estimation, I have some lift to spare, but I'm cutting it close. Also, I could throw on my 3 mm wetsuit to help add a bit more positive buoyancy if need be. What say you? Another option is something like this Al tank, but I prefer the steel if possible given that it's lighter (out of water) and slightly larger air capacity, the money difference is not a major concern.

Side note: LeisurePro should really include a bouyancy table for tanks that are sold together using a drop-down menu of options. A range of values (minimum and maximum) doesn't do much good if you are buying a tank that is not one of the two extremes.

I regularly use a Halcyon SS backplate with the smallest Apeks wing (18lb or 20lb) in a heated freshwater pool with no wetsuit with whichever UK spec Faber (typically a 12 or 15l at 232bar so about 100 or 117cuft). I don’t have a problem of being too no negative. I am not especially thin, so a stick thin person might have a different experience.

I generally find the difference between Ali and steel not to be as extreme as people make out. So much so that I suspect that the US spec Fabers must be quite different to ours. Here at least we have two styles of cylinders, lighter ones like the Fabers and heavier ‘Euro’ style ones which people like for twinsets. We have one of those in our club collection and it doesn’Tcause any problem should in the pool either.

 

[ajduplessis]

Steel "tanks" weight several tons and use for war! I would rather settle for steel cylinders, they are must lighter and designed for diving.

 

[certainmisuse]

OK, I believe I learned a thing or two here, allow me to summarize.

Based on my best estimates, the 25 lb wing should float the rig, but that's not necessarily the primary concern, it's instead perhaps that I am over-weighted in the event of a wing failure. With a 3 mm suit, 5 lb SS plate, and -7 lb tank when full, at the start of the dive, I'm very likely over-weighted. At the end of the dive? Probably OK. Now, does this even matter considering my diving profile? I have not fully decided, but probably not; again, <30 ft of water. What does have me a bit concerned is floating my rig for long periods of time (in the event where I'm stranded) without being able to ditch said weight (very easily at least) and worse, not having a working wing at all. I forgot to add that most of my diving will be from the shore. I'm considering getting at least a 30 lb wing for situations where I am far from shore and definitely planning to purchase a good quality dsmb in all cases.