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

[Eric Sedletzky]

This is how I learned to dive, except in those days wetsuits were still imperial, i.e. "1/4" Not a lot of hovering at a given depth, but early scuba was seen as an extension of skin diving.

For me the goal is to have zero gas in my bc with empty tanks at my shallow stop. If I need gas in my bc at my shallow stop with a empty tank I'm over weighted. When weighted this way, with modest sized single cylinders, diving at recreational depths or less it's quite easy to conduct the dive with little to no gas in the BC for most or all of the dive.

We used to point and laugh at the guys using horse collars……..

Tobin

This is exactly how I do it.
I also know the depth limitations of my wetsuits for no BC diving.
If you ever wanted to give someone a crash course in proper weighting just take away their BC. Most would learn real quick that they don't need near as much weight as they've been told, and/or have been lugging around.

 

[ams511]

The main thing I am worried about is that a SS plate will be too much weight in the 3mm in freshwater with a HP80, where I know in the 7mm suit with AL80 I would probably prefer the SS. If I go to an AL plate than I will need to add weight, which isn't a deal breaker, I would just like to keep the gear as simple as possible. Also if anyone can chime in: How much lift from the wing should I have?

From what you describe you need a wing in the 30 to 40 lb range. I would go with the steel plate. I have never dived Lake Pleasant but I would be surprised if you can dive it with a 3 mil 1 piece suit past the thermocline.

 

[Neilwood]

This is exactly how I do it.
I also know the depth limitations of my wetsuits for no BC diving.
If you ever wanted to give someone a crash course in proper weighting just take away their BC. Most would learn real quick that they don't need near as much weight as they've been told, and/or have been lugging around.

I know for certain that if I didn't use the rented jacket BCD that I have had so far, that I would be able to drop quite a bit of weight from my belt - the damn thing is pretty buoyant on its own. Hence my plan to get a BP&W as soon as I have money and time to do so. I know my rig is not balanced but for my type of diving (I can't ever foresee going 30m+), I don't really see it as a huge problem.

 

[halocline]

Hey Eric, a balanced rig isn't the placement of weight or even wether it's ditch able or not.
It's the calculation of the minimum amount of weight you require to remain neutral throughout the entire dive.
This eliminates the many drawbacks of being overweighted and the ability to do a controlled ascent in case of a catastrophic wing failure.

Not sure of the individual that came up with it but it's been used in DIR world for many years.


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I've always thought that the term "balanced rig" had to do with splitting up weight between the BC and the diver so that each component was more-or-less neutral at depth, hence the "balancing" between diver and BC. It's much more useful IMO to think of that as 'balanced.' What you're describing to me just sounds like being properly weighted.

 

[tbone1004]

halocline, if you split up between the two, it's impossible for doubles because you almost never need any lead

 

[decompression]

I've always thought that the term "balanced rig" had to do with splitting up weight between the BC and the diver so that each component was more-or-less neutral at depth, hence the "balancing" between diver and BC. It's much more useful IMO to think of that as 'balanced.' What you're describing to me just sounds like being properly weighted.

This is a teaching standard from the agency.


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[cool_hardware52]

Hey guys, new to the forum and diving in general. I have an Advanced Open water cert with ~20 dives, and my wife just got her Open Water cert. Currently we have been renting gear and think its time to buy personal gear.


I have been doing research on gear and like to live by the motto "buy once, cry once". So my question to the board is: "BP/W a good piece of gear for our usage? Or should we stick with traditional style BC's?". One of the main things I like about the BPW is that it creates a smaller/lighter rig by needing less lead. There are 3 main dive scenarios that I would like one BC to handle.

1. LOCAL: Local diving for me is in Lake Pleasant, Phoenix, AZ. Freshwater that will be dove with either AL80's or HP80, most likely in a 3mm suit.

2. TRAVEL: Travel diving can include just about anywhere but will most likely involve warm salt water, AL80's and a 3mm suit.

3. SOCAL: Diving in Southern California (lobster & Catalina) I will probably be wearing a 7mm suit and AL80's, although I have heard that the water is warmer than I remember (62*).


The main thing I am worried about is that a SS plate will be too much weight in the 3mm in freshwater with a HP80, where I know in the 7mm suit with AL80 I would probably prefer the SS. If I go to an AL plate than I will need to add weight, which isn't a deal breaker, I would just like to keep the gear as simple as possible. Also if anyone can chime in: How much lift from the wing should I have?

Plates have to be selected based on the *least* required ballast and wings have to be selected based on the *most* buoyant suit.

There can be suit / tank combos that for which any BP will result in an over weighted condition. The solution is *not* a larger wing. The solution is to change suit or tanks to cure the overweighting.

Assuming you are neutral in your birthday suit a 3mm and HP80 may be one of these combos. Typical 3mm suit is 3~5 lbs positive, and there are some HP80 that are very negative. The older PST's were -6 ish empty. The Worthingtons are more like -2.

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.

The solution is to stick with buoyant al 80's when diving 3mm suits…. (as an aside short tanks like HP80's are a poor choice with any BP&W as they will allow the wing to fold under the bottom of the tank when you sit down. This greatly increases the chances of a pinch flat)

If we focus on al 80's and 3mm suits then a SS plate starts to look reasonable. 3mm suit is ~+4 and and an empty al 80 is ~+4 4+4=8 and a SS plate, harness, and regulator is about -8. It's very common for divers in 3mm suits with al 80's to dive using nothing but their plate, harness and reg for ballast.


7mm suits + al 80's obviously require a lot of ballast, again this makes a SS plate a good choice.

Your wing needs to be sized for use with your 7mm suit. I have not encountered a single piece 7mm suit on a person of normal stature that was anywhere near 30 lbs positive. Typically in the high teens to low 20's If we assume your 7mm suit is + 24 lbs (far better to test *your* suit) then a 26 lbs wing is a reasonable choice. A 26 is sufficiently streamlined for use in your warm water applications.

I've never seen a 7mm suit that would require a 40 lbs wing. The largest singles wings we offer is a 40 and we sell very few of them, mostly to Public Safety Divers that are entering the water intentionally overweighted in order to conduct bottom searches.

Tobin

 

[halocline]

halocline, if you split up between the two, it's impossible for doubles because you almost never need any lead

That depends. In cold water (dry suit or very thick wetsuit) with AL80s most divers will still need lots of ballast.

---------- Post added October 5th, 2015 at 10:27 AM ----------

This is a teaching standard from the agency.

I believe you, but I'd like to know what the difference between being properly weighted (i.e not overweighted) and the "balanced rig" as you described, is.

Splitting up the weight between diver and rig is useful in cold water with a very buoyant wetsuit in case you ever needed to doff the rig at depth, so the diver doesn't end up upside down hanging on to the BC for dear life....and it can reduce the minimum lift requirement because you wouldn't need an oversize wing simply to float a rig that's loaded down with ballast. To me this is a much better use of the term "balanced", because it describes a balance in buoyancy between the diver and the rig. I don't really care how DIR uses the term.

 

[beaverdivers]

The solution is to stick with buoyant al 80's when diving 3mm suits…. (as an aside short tanks like HP80's are a poor choice with any BP&W as they will allow the wing to fold under the bottom of the tank when you sit down. This greatly increases the chances of a pinch flat)

Agreed!

If we focus on al 80's and 3mm suits then a SS plate starts to look reasonable. 3mm suit is ~+4 and and an empty al 80 is ~+4 4+4=8 and a SS plate, harness, and regulator is about -8. It's very common for divers in 3mm suits with al 80's to dive using nothing but their plate, harness and reg for ballast.

What happens if the diver at the beginning of the dive has an inflator or wing or reg failure at 100+ ' ? For fun, let's add a down current. What would you do?

 

[elgoog]

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

Agreed! What happens if the diver at the beginning of the dive has an inflator or wing or reg failure at 100+ ' ? For fun, let's add a down current. What would you do?

Reg failure -> That's what your buddy's there for, get her backup reg
Inflator failure -> Oral inflation
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. As you get higher up in the water column, swimming is going to get easier and your buddy is hopefully going to be there to help you if you need it as well.
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.

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.