Another bp/w thread

[Skydiver1]

Hi,

Ive become indoctinrated by the constant stream of bp/w propaganda on this website.

I'm inexperienced and was looking buying the Halcyon Eclipse Infinity System + ACB steel backplate with 40lbs lift for diving in UK and Ireland. I dont know if the 40lbs is too much, but from what i've read it depends on where the weight is going to be put, and I have no idea about the setup until I get some further instruction.

Aside from that, I was wondering if a SS backplate would be okay for diving in warmer locations. The weight of the steel would probably be an issue for flights, but would a SS backplate be overkill for diving for example in Cozumel where a 3mm wetsuit suffices?

 

[TSandM]

Required lift is a function of how you rig your gear, and what exposure protection you are using. The wing has to do two things -- float your equipment at the surface, and compensate for the gas you are going to exhaust into the water, and the buoyancy you can lose from your exposure protection at depth. It's pretty easy to figure out what you need to float your gear at the surface -- you can take the weight of the backplate (5 or 6 lbs) and metal accessories (2 lbs), and add the maximum negative value of the tank you are using, when full (generally in the 6 to 8 lb range, unless you are either using the highly negative Fabers or using extremely large tanks). Add in any ballast you attach to the rig itself, and you'll have the lift needed to float your gear.

Exposure protection can be a little more difficult to sort out. Thick neoprene can lose a lot of lift at depth (I have seen estimates of a good 7 mil full suit losing over 20 lbs of lift at 100 fsw). A dry suit, when flooded, will lose some of its lift, but how much will depend on whether the suit can still hold any air, and how quickly and to what degree the undergarment saturates. Still, in cold water, it's probably reasonable to assume that you can lose somewhere in the neighborhood of 25 lbs or so of lift.

The bottom line is that, for most single tank cold water diving, a wing in the 30 to 35 lb range will suffice.

As far as whether a stainless plate will work in warm water, that depends on how much ballast you need in a 3 mil suit. If the answer is five pounds or more, a stainless plate will be fine, although you might end up with no ditchable weight (and that's a decision you have to make). If you use less than five pounds of ballast, you will be overweighted to some degree with a steel plate. I know, for me, with an Al80 and a 3 mil suit, I need two pounds more than my backplate, so using the steel plate works just fine.

 

[Skydiver1]

Thanks for the detail TSand

 

[DevonDiver]

My first BP&W was a 40lb Eclipse. It was over-kill.

I dived in the UK, with drysuit, SS backplate, canister light, 15l steel tank, 3l steel pony... etc... I still didn't really need that much lift.

It's best to work it out for yourself (search the forum for the 'Wing Lift Calculator').

 

[Ste Wart]

I recently ditched my SS BP for weight reasons; it was killing me at airports. My old Zeagle BP weighed in at around 3 kgs, it dominated my dive kit. Also when diving in warm waters I was exceedingly negative, something like 3 kilos!!!
Anyway I switched to an IST BP, which weighs 700gms, much better and reasonably priced, under £50.
As regards the wing, seeing as you're in Ireland why don't you check out the APEKS WTX rec wing. It's a substantial amount cheaper than the Halcyon and IMHO a far better wing (I use their APEKs wings for Tech as well). The lift on it is more than enough for single tank diving, maybe too much.

 

[Skydiver1]

My first BP&W was a 40lb Eclipse. It was over-kill.

I dived in the UK, with drysuit, SS backplate, canister light, 15l steel tank, 3l steel pony... etc... I still didn't really need that much lift.

It's best to work it out for yourself (search the forum for the 'Wing Lift Calculator').

Was it overkill because of the dry suit?

According to TSands figures, with metal backplate etc, and compression of a neoprene suit at 30 meters, you could be looking at 36lbs negative buoyancy. I'm probably wrong in my calculation. I dont really understand that buoyancy calculator, especially the American units for the tank sizes.

 

[BDSC]

Ahhhhh yes. The simplicity of a BP/W!

 

[DevonDiver]

It was pretty simple when I bought my first Eclipse. Every jacket BCD I had owned had 30-45lb of buoyancy...so I just stuck with what I knew. Simple...

But the unit 'grew' with me. As my knowledge developed, I was able to fine tune my requirements. The BP&W allowed that to happen perfectly.

If I hadn't moved to a BP&W, I'd still be diving with an inappropriate amount of lift...

 

[fnfalman]

I don't know what exposure suit or the number of tanks the OP wanted to use with the Infinity so I'll refrain from making comments on the wing lift capability.

However, why is a SS plate too heavy for traveling? That's 6lbs of plate plus maybe 1lbs of webbing. The lightest travel BC is about 4-something pound. I'd suggest carry less clothes to compensate for the additional 3lbs. If I were to go on a warm water tropical dive vacation, I'd rather spend the time enjoying the dive with my BPW than using a jacket BC.

 

[Ste Wart]

However, why is a SS plate too heavy for traveling? That's 6lbs of plate plus maybe 1lbs of webbing. The lightest travel BC is about 4-something pound. I'd suggest carry less clothes to compensate for the additional 3lbs. If I were to go on a warm water tropical dive vacation, I'd rather spend the time enjoying the dive with my BPW than using a jacket BC.

The main reason is that here in Europe we only get around 20kgs of checked luggage, compared to the 25kgs you get in the US.
I recently flew from London to Chicago (the end destination was a dive holiday in Roatan). I packed minimally. Ally Backplate, wing, fins, 2 masks and 3mm Chicken vest, plus clothes for the week and it came in at 22Kgs (My regs were in my hand luggage, as always). So although I was fine for US travel I would have payed 2kgs excess if I'd had been travelling anywhere else, imagine if I'd have still had my SS BP!!!!!
To give you an idea on how ludicrous airlines have become, Emirates (one of the main airlines to go to the Maldives) charge £30 ($45) per excess kilo. They no longer accept Dive luggage as sports equipment. For travel an Ally or Soft plate is the only way to go.