Backplate questions for double tank diving

[elgoog]

Hi -

I'm planning on starting doubles diving some time next year and have begun to look for the components I need for that on the used market. I've seen a ton of posts about wing size selection and feel like I have a good idea of what I need there but had some questions about the backplate.

- I will be diving with HP100 doubles filled with EAN32 in a drysuit. From reading on here, it seems like this combo almost requires a light backplate (AL, Kydex, etc) due to the weight of the bands, regs, manifold that are higher up (forward?) on the diver. I realize this is totally personal from diver to diver but I'm curious to know if there's anyone who dives this combo as a balanced rig with a steel backplate.
If it helps at all, I currently dive a single HP100 with a DSS steel BP (6lb), the weight plates (8lb) and a 10lb weight belt in my drysuit with 400g Thinsulate undies.

- Is there a particular shape of backplate that's better for doubles? As in flatter vs deeper? I read that DSS plates are relatively flatter and Halcyon plates have a deeper V. Not sure about any of the other brands (DGX, HOG, Light Monkey, etc).

Here's why I ask - The components I need to acquire, at the very least, are a doubles wing, tank bands and a manifold. If it turns out that a steel backplate is not preferable, I would just get a new DSS doubles package with a Kydex plate - the cost of this is attractive enough that looking for a separate wing and plate (at the prices I've seen on SB, eBay) and then buying a harness doesn't make sense to me.

Thanks in advance,
elgoog

 

[tbone1004]

depends on the HP100. If it's a Worthington you are adding the following
3.3lbs -tank w/ valve
~3lbs manifold
~4lbs bands
~3lbs regulator
Depending on the tank, you'll be somewhere between 10 and 14lbs more negative with doubles than you are in singles. Since you are currently wearing 18lbs, there is no need to abandon your steel plate.

 

[rhwestfall]

if you are diving cold water, there is likely no reason you want to go to the kydex. my singles rig (and all of us are different) is a DSS SS long w/ weight plates (so 16# +/-), and I use no lead with HP100/HP120 steels, and actually may be slightly over-weighted. Double HP100/double LP85 on a bare plate (no plates) still has me with no additional weight. I dive a DUI CF-200x w/ Bare 400g quilted under-garments. This is fresh water.

I'd try what you have first...... you can always buy a plate later.

 

[runsongas]

can probably have the steel plate work, may need a tail weight instead of belt for trim

i have a pair of worthingtons and a pair of pst's and use 6 pounds of weight on a belt with a 5lb steel plate.

doubles wings are pretty cheap used if you don't mind horseshoe. the donut wings are a bit more expensive.

 

[rhwestfall]

I'm sure there will be some killer Black Friday deals on wings....

 

[RandomGuy1]

I dive a DSS bp/w for singes and a halcyon bp/w for doubles. I don't really notice much difference between them as far as fit/ comfort between the depth of the V. I dive the halcyon rig with a ss backplate with HP100 doubles every week with no issues, but carry no weight anywhere else. At the start of the dive I have to have air in my DS and my wing, but by the time I'm at less than 1000psi, I have no air in the wing and at 500psi I'm pretty much starting to get uncomfortable shrink wrapped but its doable.

 

[PfcAJ]

Steel plate is the jack of all trades. I only recently got an aluminum for travel. You'll be fine with the steel.

 

[cool_hardware52]

Hi -

I'm planning on starting doubles diving some time next year and have begun to look for the components I need for that on the used market. I've seen a ton of posts about wing size selection and feel like I have a good idea of what I need there but had some questions about the backplate.

- I will be diving with HP100 doubles filled with EAN32 in a drysuit. From reading on here, it seems like this combo almost requires a light backplate (AL, Kydex, etc) due to the weight of the bands, regs, manifold that are higher up (forward?) on the diver. I realize this is totally personal from diver to diver but I'm curious to know if there's anyone who dives this combo as a balanced rig with a steel backplate.
If it helps at all, I currently dive a single HP100 with a DSS steel BP (6lb), the weight plates (8lb) and a 10lb weight belt in my drysuit with 400g Thinsulate undies.

- Is there a particular shape of backplate that's better for doubles? As in flatter vs deeper? I read that DSS plates are relatively flatter and Halcyon plates have a deeper V. Not sure about any of the other brands (DGX, HOG, Light Monkey, etc).

Here's why I ask - The components I need to acquire, at the very least, are a doubles wing, tank bands and a manifold. If it turns out that a steel backplate is not preferable, I would just get a new DSS doubles package with a Kydex plate - the cost of this is attractive enough that looking for a separate wing and plate (at the prices I've seen on SB, eBay) and then buying a harness doesn't make sense to me.

Thanks in advance,
elgoog

Do the math. Add up all the components you have that don't float and compare that to the buoyancy of your suit when it's fluffed up a little. (added gas for warmth at an extended shallow stop)

If your base rig, i.e. 2 x empty HP 100's, bands and manifold, 2 x regulators, can light, and plate is less than the buoyancy of your suit use your current SS plate. If your base rig provides *more* ballast than is required to keep you and your slightly inflated exposure suit at your shallow stop with near empty back gas tanks a less negative plate is one way to reduce the ballast you are carrying (by about 4 lbs)

Gotta have the actual numbers to make an informed choice.

Tobin

 

[Lorenzoid]

Have you not read the hundreds of posts advocating the BP/W over a traditional BC because one of the major advantages is that you can use the same plate for both single and double tank diving?

It's true. I use my DSS steel plate with singles AND doubles--in my case, Worthington LP 85s. Steel versus aluminum plate is only a few pounds difference. It's not like this difference is going to leave you severely overweighted or underweighted. (tbone did the math for you.) I suggest you try diving your HP 100s with your present plate, and see how it works out for you before buying another plate. Used doubles wings are easy to find, as you mentioned. I would think the main advantage of a lighter plate would be to enable you to shift some weight to the tail if you find you need to do that to improve your trim. But you won't have a feel for trim until you try it. I'm fairly new to doubles as well, and I can only speak from my own (meager) experience.

As for the depth of the bend, it's true that the DSS plates have a shallower bend than some others, but it's hardly significant enough to make them unsuitable for doubles or something. Bolts can be adjusted in length.

 

[cool_hardware52]

Have you not read the hundreds of posts advocating the BP/W over a traditional BC because one of the major advantages is that you can use the same plate for both single and double tank diving?

It's true. I use my DSS steel plate with singles AND doubles-.

In my experience it's often possible for a diver to use the same back plate for singles and doubles, but not always. I try to inform my customers that a different plate *might* be required when switching from singles to doubles. This of course depends on selection of cylinders and their buoyancy characteristics and the choice of exposure suit.

What is often missed by those seeking their first back plate and wing, who think they *may* want to dive doubles in the future is the other costs of moving to doubles.

A couple sets of doubles, a milk crate full of regulators, stage bottles, drysuit and a couple sets of undies, can light, training, stage bottles, deco bottles, computer etc. all add up. (admittedly not every doubles diver needs all these items, but the pile of stuff grows pretty fast)

The cost of a 2nd Back plate at this point is not zero, but it can be a tiny part of the total cost. This is why I encourage new BP&W divers to optimize their rig for the diving they are doing now. If and when doubles come into the picture there is a good chance their first plate will work, but if they need a 2nd plate their wallet will already be numb. Trying to predict what they will be using for tanks, and exposure suit if and when they make the transition to doubles and basing their single rig purchase on these unknowns is usually a bad idea.

Tobin