BP/W..... one BC to rule them all??

[boulderjohn]

Agree.
Although, for a 1st stage failure on a single tank setup, you would need some redundant gas supply (pony bottle, buddy, whatever)

Not really. Are you taking about a free flow, which can happen, or a full stop of the regulator, which should be close to impossible? If the former happens, dealing with it is taught in the basic OW class. If the latter happens and you have no one around, you would have to go to the surface with a CESA or buoyant emergency ascent, but you would make it. That is an incredibly rare scenario.

Disagree (on that being beaverdivers' point).

My fault--obscure pronoun antecedent. I was saying that it was Tobin's point, not beaverdiver's.

---------- Post added October 5th, 2015 at 02:00 PM ----------

Hey guys, thanks for all the great replies. For my local lake I was wearing 12 pounds of lead with a jacket and Al80 and a 2:1 shorty. I'd consider myself a "lean" diver at 7% body fat.

I am by no means a lean individual--not even close to what you just described. If I am diving in a local lake, I am in much nippier water than you are, and I wear a dry suit with medium underwear. If I am using an AL 80 tank with a 6.5 SS backplate and a canister light as well, I wear 8 pounds of lead, which gives me a little more weight than I really need. My inclination, then, is to believe you should try less weight the next time you are there.

 

[elgoog]

While the shorty suits where fine for the ~75* surface water for the 100* day, what another poster said was pretty accurate. "you won't stay long past the thermocline". I haven't dove tropical waters yet, and see why no suit or a shorty would make sense on the surface, but do people rock thicker suits to go deeper?

It's not just depth but also overall time in the water that will bite you on the later days. If you do 3-4 dives per day in 75-80F water every day, depending on your cold tolerance you might start feeling colder around day 3 or so.
You don't necessarily need a thicker wetsuit - a good hood will give excellent bang for buck in terms of keeping you warmer (skipping this was the mistake I made last time). Also try base layers like LavaCore under your shorty, they don't add any extra buoyancy like neoprene and provide a decent amount of thermal protection for warm water.

So far I am thinking an AL plate with some trim pockets and a ditch able belt looks like the best choice as adding or subtracting lead seems a lot easier than limiting what tanks and suits I can jump in with, especially when I am going from fresh to salt and plan on flying my gear.

As others have already suggested, do a proper weight check first before you buy anything. You'll be surprised how much weight comes off (I sure as hell was).
Some other things to consider when deciding between AL and steel BP.
For limiting which tanks and suits you can use - With your 2mm shorty, steel BP in fresh water, you would switch from steel tank to AL (probably still be overweighted). It's way easier to get an AL tank rental than a steel in most places. Is there a case where your only option is to dive a steel tank (either due to LDS availability or something you own)? In general, steel tank with a thin wetsuit is not a great idea, especially if you start going a little deeper. Once you start wearing thicker wetsuits or drysuits, steel BP becomes more and more preferable.
For trim pockets - They are convenient for doing weight checks and to figure out trim but I would not want to use them as a permanent solution. When you put them on your tank bands, you will have to empty them out every time you're swapping tanks - for me, this was quite annoying.
For fresh to salt - Steel backplate will help you here as you will need more weight.
For flying your gear during travel - Steel plate isn't that terrible to fly with, I think they're usually 2lb heavier. Depending on how close you are to the baggage limit, this may or may not be a factor.

Not really. Are you taking about a free flow, which can happen, or a full stop of the regulator, which should be close to impossible? If the former happens, dealing with it is taught in the basic OW class. If the latter happens and you have no one around, you would have to go to the surface with a CESA or buoyant emergency ascent, but you would make it. That is an incredibly rare scenario.

I guess I meant any OOG scenario. I gather those are quite rare in terms of happening due to equipment failure but I was playing along with the scenario presented.

 

[dmaziuk]

If we assume you are neutral in swim trunks and all you have added is a 2mm shorty (positive by maybe 2 lbs) and an al 80 which will be about +3 empty in fresh water why do you need 14 lbs of ballast? (12 lead, 2 for your reg) ? It suggest to me that you are over weighted.

"Lean" body means you size the jacket by height and have this lose heap of fabric floating around your belly. +6lbs easy unless there's an air bubble in there as well.

 

[dumpsterDiver]

....
Assuming your 3mm suit is +3 in fresh water and your reg is -2 and your HP 80 is -2 you are already over weighted with *no* back plate. If you have a PST HP 80 you are *waaay* over weighted.

Tobin

FINALLY, some sense.. The OP specifically asked if a steel plate was OK with a hp steel 80 and a thin suit in FRESHwater. The answer is simply "No, hell no". Not so sure why it took so long to get there.

 

[tbone1004]

Hey guys, thanks for all the great replies. For my local lake I was wearing 12 pounds of lead with a jacket and Al80 and a 2:1 shorty. I'd consider myself a "lean" diver at 7% body fat. My wife was wearing only 8 pounds in her jacket but was diving a HP80 with a shorty. For reference when I was diving in cold Cali waters I was wearing 16-18 pounds of lead for a 7mm and AL80 in a jacket bc. While the shorty suits where fine for the ~75* surface water for the 100* day, what another poster said was pretty accurate. "you won't stay long past the thermocline". I haven't dove tropical waters yet, and see why no suit or a shorty would make sense on the surface, but do people rock thicker suits to go deeper?So far I am thinking an AL plate with some trim pockets and a ditch able belt looks like the best choice as adding or subtracting lead seems a lot easier than limiting what tanks and suits I can jump in with, especially when I am going from fresh to salt and plan on flying my gear. What say the board?

we need to know which HP80 it is.

Diving deeper with thicker wetsuits is bad, for multiple reasons, but I don't advocate diving below about 70ft in anything thicker than a 7mm full suit.

16lbs sounds about right for 7mm, al80, jacket, in the salty stuff. For that, with a steel plate you'd be down around 6lbs which is good, and depending on the steel tank, no lead at all. Perfect place to be.

If the surface is 75f, I'd probably be in a 5mm with a light hooded vest depending on dive duration, and I have a very good cold tolerance. I can do 55f water for about an hour in a bathing suit and a good hood, but that doesn't mean it's smart.

Personally in your situation I'd still get a steel plate but I would use an AL80 instead of the HP80's. HP80's suck unless you're wicked short. They're just all around not great tanks. Pick up a few LP72's, or AL80 if you're over about 5'8" and you'll be better off. HP100's if you're buying tanks.

I don't like trim pockets, but that's just me. You shouldn't need them. If you're concerned about weight for travel, or you really do want to dive in that shorty with a HP80, then I'd get a kydex plate from Tobin at Deep Sea Supply and call it good. It's one of the best and lightest travel rigs on the market.

 

[turnburglar]

Diving deeper with thicker wetsuits is bad, for multiple reasons, but I don't advocate diving below about 70ft in anything thicker than a 7mm full suit.

If you don't mind, can you elaborate on this? I have been down to 90FSW in a 7mm suit plus a 2mm shorty underneath. If there is a safety situation I am not aware of please inform me.

16lbs sounds about right for 7mm, al80, jacket, in the salty stuff. For that, with a steel plate you'd be down around 6lbs which is good, and depending on the steel tank, no lead at all. Perfect place to be.If the surface is 75f, I'd probably be in a 5mm with a light hooded vest depending on dive duration, and I have a very good cold tolerance. I can do 55f water for about an hour in a bathing suit and a good hood, but that doesn't mean it's smart.Personally in your situation I'd still get a steel plate but I would use an AL80 instead of the HP80's. HP80's suck unless you're wicked short. They're just all around not great tanks. Pick up a few LP72's, or AL80 if you're over about 5'8" and you'll be better off. HP100's if you're buying tanks.I don't like trim pockets, but that's just me. You shouldn't need them. If you're concerned about weight for travel, or you really do want to dive in that shorty with a HP80, then I'd get a kydex plate from Tobin at Deep Sea Supply and call it good. It's one of the best and lightest travel rigs on the market.

Thanks for the advice. I am starting to think my next wet suit will be a full 5mm and then I will still have my 2mm shorty. Since I do want to spend real time past the thermocline and plan on doing multiple dives a day even if its 100F air temp (phoenix) I'll probably be better off on the bottom, and just smart about getting the suit off as soon as I get out of the water. The main reason I was talking about HP80's is because my wife likes diving them, but I think I'll take your advice and buy/rent AL80s especially for freshwater and get a SS BP. It's a plus that AL80's can be had pretty cheap, and are a common rental tank. I was looking at steel tanks, and think the HP117 looks like a good size if I had to drop the coin. Maybe when I get Nitrox certified I'll grab one to really make the most of my bottom time.

 

[halocline]

If you don't mind, can you elaborate on this? I have been down to 90FSW in a 7mm suit plus a 2mm shorty underneath. If there is a safety situation I am not aware of please inform me.

Don't take everything you read on an internet forum literally; there's no magic depth (like 70 ft) at which thick wetsuits become problematic. In general the deeper you go, the more the wetsuit will compress, and as such you will be more negatively buoyant. At some point, depending on a few things in your gear configuration, you will want to have a back up source of buoyancy in case there's a problem with your BC. However, this is almost exclusively an issue for technical diving with double tanks and lots of other heavy gear.

The practical issue for a recreational diver in a thick wetsuit in cold lakes is that the as the water gets much colder at depth via thermoclines, the wetsuit is providing less insulation. In the ocean you don't typically have the same type of thermoclines, although it can get somewhat colder at depth. Most cold water divers end up in dry suits eventually, as nobody enjoys getting cold on a dive. The drysuit also provides a redundant source of buoyancy which technical divers want.

Regarding tank choice, I would suggest that you consider how much gas you really need, what works best for your trim, and what your ballast requirements are and then choose accordingly. There's no advantage to using huge tanks unless you need lots of gas, and different tanks feel differently in the water. Any time you can rent a specific type of tank before you buy it's a real plus.

 

[tbone1004]

Similar to Halocline, the number is pretty arbitrary, I use somewhere around 20m as my number between dry and wet if it's "cold". I'll make exceptions if I'm only in my 5mm which is old and crushed down to about a 3mm right now since it won't lose much buoyancy, but he hit the two reasons.

thermoclines suck so your 7mm that is good at the surface is now down somewhere around 3mm at depth which makes for uncomfortable bottom time and compounding hypothermia is not good. Dress for the water not the air, you can always get out of the suits when you hit the surface.

compression is dependent on how durable the neoprene is. "stretchy" neoprene compresses a lot faster and if your suit has 20-25lbs of positive buoyancy at the surface, that can drop quite quickly to 10lbs and now you're 10-15lbs negative which starts to necessitate the need for ditchable weight since that is a lot of weight to kick up off the bottom, now you've ditched your weight so you can't hold a safety stop, and while CESA's from that depth won't kill you, they certainly aren't great for you....

 

[beaverdivers]

Ermahgerd, your crusade against BP/W continues. Since you're replying to SB posts now, maybe you could take some time to update us on the worst case scenarios you mentioned here - http://www.scubaboard.com/forums/basic-scuba-discussions/513269-bp-w-me-my-son-19.html#post7495284

This example is the update. BTW, I do not have a problem with a BP/W when used properly.

Reg failure -> That's what your buddy's there for, get her backup reg

What if you buddy is up current & out of reach?

Inflator failure -> Oral inflation

Agreed!

Wing failure -> Assuming you didn't breath at all on the way down to 100' and you were wearing a super cheap 3mm that lost all it's buoyancy at 100', you might have to swim up max 8lb at the very bottom. That's not super easy but it's not impossible either.

What if you have a medical issue that is exacerbated by this incident? For instance, leg cramps.

Downcurrent -> If you're on a hard bottom AND once you get sorted out on breathable gas with your buddy, you can move sideways to get out of the downcurrent before you start your swim up.

Your buddy is out of sight, you have leg cramps & your overweighted without a hard bottom!

If you're 100' in midwater over a 500' deep chasm in a 3mm on an AL80, have a failure and get caught in a downcurrent, you would ... uh, I don't know, I would try not to get into that situation in the first place.

Have you ever been diving a wall in the ocean?

 

[elgoog]

So I'm changing the order of what you said but this is how I understand your scenario - you're overweighted (when did this condition get introduced, BTW?)+ have a leg cramp + are diving a wall with no hard bottom + are caught in a down current + your buddy is simultaeneously caught in an up current AND now you had some sort of BC or reg failure.

Is that right? I'd like to make sure it is before I spend any time trying to figure out a death defying maneuver out of this predicament.