Another Al v.s SS BP

[eelnoraa]

The weight difference between AL plate and SS plate is at most 4lb. When in doubt, go with AL plate. It is very easy to add 4 lb somewhere. But nothing can be done if you are over weighted by 4lb. I personlly prefer AL plate in warm water 3mm wetsuit kind environment. It allows me to put weight on upper, lower cam bands, or even tank neck for better trim.

 

[Schwob]

Curious because I wonder myself what to buy going forward in that regard:
When those of you who dive a BP&W in a "not so tec mode" and bring your light set-up w/o redundant wing and favor doing so with a SS BP and no ditch-able weight - are you always comfortable? (with redundant wing and or sturdy liftbag this is a moot question).
I mean you probably carry at least an SMB and have redundant buoancy in that way and maybe you are weighted such that you are fairly certain you could swim up anyway if all else fails... I am wondering about the mental aspect... at what point are you still feeling comfortable with out and at what point would you choose to have ditch-able weight on you (over not having it)?
Do you practice ascending the wing entirely empty from time to time from deeper depth to arrive at that "mental-comfort" (coming from practised certainty then) - or what do you do to arrive at the conclusion that you indeed will not need ditchable weight?

 

[dumpsterDiver]

I think the important consideration for the OP is the potential for using steel tanks. If you progress in your diving adventures and decide that the larger, heavier, high capacity steel tanks are something you might want to use, then I would definitely avoid a SS plate. Being small and using a big steel tank with a thin suit, you are going to be heavier than you need to be with an aluminum plate. Adding more unditchable ballast (in the form of a SS plate) provides no benefit and could affect your safety.

 

[gcarter]

Hey guys I'm making the switch to a BP/W set up and trying to get some clarity on Al or SS. I currently dive a scubapro litehawk with 8 lbs on a weight belt with a 3mm. All my dives have been in 65 to 80 degrees. All Al 80 tanks and my reg setup is about 4 lbs. Im not a big guy, 5'7 and weigh 145. I figured the litehawk is 5.2lbs dry weight which is about the same as most SS backplates. So with the addition of a harness, buckles and tank strap. would be about 2 -3lbs. So essentially I would be be overweighted by a couple pounds if I do SS and need about 4-6 pounds if I go the route of Al. I do travel for all my diving but the weight isn't a concern. Im leaning to SS but open to anyone advice on if this calculation seems off or any advice from those who have dove both ss and Al bp.

First thing to understand is that you are complicating your analysis by mixing apples in with the oranges.

1) your current weighting is 8 lbs.
2) You are not indicating any change in tanks used, regulators used, wet suit used, or any other equipment. They are therefore irrelevant to the overall question, although they might have some bearing when looking at a balanced rig.
3) Dry weight of your BCD is not relevant to anything other than packing for a trip What matters is buoyancy, and if yours is like most, it is probably at least a pound or two positively buoyant.

Typical SS plate is 6 lbs. Accounting for all of the other "stuff" required for the plate and the buoyancy inherent in the BCD it replaces, you will likely be able to ditch the 8 lbs of weighting (that is what my move from a SeaQuest Balance BCD did for me) but you are unlikely to be overweighted.

A typical aluminum plate is 2 lbs. So if your experience is like mine, that would take 4 lbs off of your belt.

 

[Jim Lapenta]

I never use a dual or redundant bladder wing. My weighting even with a single LP 95 in a 3 or 5 mm wetsuit is such that I don't worry about having ditchable lead. Worst case scenario I dump the rig. I will float in the exposure suit. If I'm diving al 80's in a 5 mil I'll either put on a MAKO rubber belt with what extra lead I need in individual pockets under the crotch strap or if I don't feel like using a belt I'll bolt the weight plates to my DSS steel plate.

Usually the belt is the option when I'm teaching because it allows me to carry a couple extra pounds that a student might need. We usually try to get them correct before the dive but every so often someone needs an extra 2 lbs or so at the end of the dive. If I'm diving for fun or solo and don't want to mess with the belt, in a 5 mil I am just about perfect with an al80 at 500-700 PSI and using my steel plate and bolted on weights.

I don't need weight I can drop to feel comfortable.

 

[jeffmg]

SS works for literally anything, buy once cry once. Even in double hp130s. Always carry on the backplate, never really noticed a huge difference underwater

 

[Lorenzoid]

On the rare occasions I dive a steel 120 with my steel plate in warm water, which is pretty much only in Cozumel for me, I use a 5 mm suit to help offset the weight. Neoprene in the tropics is no joy, and at the beginning of the dive I might let a little water into the neck to cool myself off, but since a 120 allows a long dive, by the end of the dive I am rarely wishing I had a thinner suit.

 

[cool_hardware52]

I am thinking about going to a BP/W as well, for travel purposes. I have a Zeagle Brigade now and with a steel 120 HP and no exposure suite I use 2 lbs of lead. When I wear a 3/2mm I am a little heavy with 4 lbs. I only plan to dive warm saltwater and use 120 steel tanks often. For travel I am more concerned with luggage space than I am weight. I want to be able to carry on only for short trips. Would an AL plate be better in this situation?

Plate material, i.e. Stainless vs lightweight (Kydex or Aluminum) is a for me a function of required ballast. Warm salt water implies thin wetsuits (~3mm) and steel 120's are typically about -2 lbs empty.

If we start with a neutral diver add 3-5 lbs of buoyant exposure suit, offset with 2 lbs of empty cylinder and ~2 lbs of regulator you can see that the ballast provided by a SS plate will over weight the diver. Even with a lightweight plate there's a chance the diver may end up very slightly over weighted.

With alum 80's the stainless plate starts to look better, as alum 80's are ~+4 lbs empty vs -2 for most steels. That 6 lbs difference make the ballast an SS plate provides welcome.

Keep in mind that the dry travel weight difference between the typical SS plate and Lightweight plate is about 3 lbs. many people assume it's more like 10 lbs. It isn't.

It's also the case that even with a SS plate often a BP&W, (with a smaller Warm water wing) is lighter (travel weight) than many full featured BC's, or at most 1-2 lbs heavier.

Tobin

 

[dumpsterDiver]

Plate material, i.e. Stainless vs lightweight (Kydex or Aluminum) is a for me a function of required ballast. Warm salt water implies thin wetsuits (~3mm) and steel 120's are typically about -2 lbs empty.

If we start with a neutral diver add 3-5 lbs of buoyant exposure suit, offset with 2 lbs of empty cylinder and ~2 lbs of regulator you can see that the ballast provided by a SS plate will over weight the diver. Even with a lightweight plate there's a chance the diver may end up very slightly over weighted.

With alum 80's the stainless plate starts to look better, as alum 80's are ~+4 lbs empty vs -2 for most steels. That 6 lbs difference make the ballast an SS plate provides welcome.

Keep in mind that the dry travel weight difference between the typical SS plate and Lightweight plate is about 3 lbs. many people assume it's more like 10 lbs. It isn't.

It's also the case that even with a SS plate often a BP&W, (with a smaller Warm water wing) is lighter (travel weight) than many full featured BC's, or at most 1-2 lbs heavier.

Tobin

I'm sure you figure for the 120 steel is probably correct, but I had a BC failure when wearing a LP 120 steel tank and wearing near zero buoyant exposure protection. I ended up quite negative at 160 feet and opted to just swim up and it was more strenuous than I liked. It left a big impression on me about being "extra heavy" and having nothing to ditch. Incidentally, I had another total BC failure this weekend - with the OP assembly popping off.

The big steel tanks hold what, like 10 lbs or more of air, so when they are full, they are really pretty negative.

I think cold water divers who need tons of ballast forget how much different warm water is with respect to ballast requirements.

 

[cool_hardware52]

I'm sure you figure for the 120 steel is probably correct, but I had a BC failure when wearing a LP 120 steel tank and wearing near zero buoyant exposure protection.

Negative steel cylinders with no exposure protection is almost always going to result in an over weighted diver.

The cure is either buoyant tanks, more wetsuit, or a drysuit.

Wetsuits of course compress and result in the diver becoming increasingly negative with respect to depth, but they also rebound on the way up (incompletely and slower than they compress) but still a rebounding wetsuit means the as the diver swims up the task gets easier. That's handy as one gets fatigued.

With little to no suit the job of swimming up remains pretty much constant all the way to the surface, and if the diver is genuinely over weighted staying at the surface is a workout too.

This is exactly why I try to get divers to be as close to properly weighted as possible, doing so reduces the problems associated with any BC failures, or panicked divers forgetting to add gas to a functioning BC.

Glad to hear you had the fitness to deal with the problems.

Tobin