?'s About Bp/w and Weighting

[DiverMo]

I just recently got my C-card (last Sept.) and have been doing research into BC's. Based on my readings, I have decided to go with a bp/w, or at the least a back inflation bc like the Transpac II. I have noticed numerous postings about having to wear no weight when diving with a SS wing - usually when diving in tropical waters and not wearing any type of exposure suit - so my question is: Is this safe? When not wearing any weight, what happens in an emergency when you need to surface and you can't ditch weight? Would it then become preferrable to always wear some sort of suit, even if it's a shorty, to achieve some type of positive bouyancy? I live in MI, so a full length suit of one kind or another is always worn around here, but I also like to travel and dive in warmer climes, so my gear must accomplish both. Sorry if this is going over ground already covered, but I am rather new to the whole bp/w theory, so I'm just trying to fill in the blanks. Thanks.

MO

 

[MXGratefulDiver]

I just recently got my C-card (last Sept.) and have doing research into BC's. Based on my readings, I have decided to go with a bp/w, or at the least a back inflation bc like the Transpac II. I have noticed numerous postings about having to wear no weight when diving with a SS wing - usually when diving in tropical waters and not wearing any type of exposure suit - so my question is: Is this safe? When not wearing any weight, what happens in an emergency when you need to surface and you can't ditch weights? Would it then become preferrable to always some sort of suit, even if it's a shorty, to achieve some type of positive bouyancy? I live in MI, so some type of full length suit is always worn around here, but I also like to travel and dive in warmer climes, so my gear must accomplish both. Sorry, if this is going over ground already covered, but I am rather new to the whole bp/w theory, so I'm just trying to fill in the blanks. Thanks.

MO

In an emergency you should be able to swim up your equipment ... even with no air in your BCD (or wing). Dropping weights is often overstated in OW classes ... the primary place you would want to do so in an emergency would be on the surface, to make it easier to STAY on the surface. And even that shouldn't be necessary unless you have a complete failure in your inflation system ... even in an OOA, once you're on the surface you can manually inflate your wing to remain afloat.

In colder water, you will either be in a wetsuit, which provides some bouyancy ... or in a drysuit, which provides a redundant inflation system (in an emergency). So it's less of an issue. Also, in this case you will have to wear some additional weight (BP's usually provide 5 or 6 lbs of "weight").

Keep in mind that dropping weights at depth WILL result in an uncontrolled ascent ... and in all but the most dire emergencies, is something you want to avoid.

... Bob (Grateful Diver)

 

[The Kraken]

The purpose of weight is to overcome positive buoyancy at the surface in order to descend if one is positively buoyant with an empty air bladder (the bladder serving the same purpose in both B/C and B/P-wing). The purpose of the BC or B/P-wing is to offset that weight when at depth.

When diving a very thick wet suit doubled up (farmer john and jacket) one usually is a tad bit over weighted at depth due to the compression of the wet suit with the increase in pressure with a resultant loss of buoyancy.

In most situations within THE RECREATIONAL DIVING ENVIRONMENT if one is diving without a great deal of inherent buoyancy, the amount of weight comprised by the tank//BC/BP-wing set up is not so great at depth that the diver can't swim it to the surface or that the bladder cannot overcome with it's available lift capacity.
Keep in mind that this scenario is predicated upon the use of a single tank.

Hope this helps . . .

Safe dives . . .
. . . safer ascents!!!

 

[scubadobadoo]

The above posters always provide good advice, so I agree with them. I will add that I personally like to have about 2-4 pounds to ditch that way if I need to (hopefully never unless I have made more than one mistake) ditch weight, I won't pop to the top like a cork. One really only needs to ditch a few pounds to become positve. Ditch 5 or more and you are flying! Not a good thing.

I just got a weighted sta and if you add that to a SS BP/W you already have 12 pounds in most cases. Nonetheless, with a single AL80 and VERY thick undergarment and a dry suit I still need to add 14 more pounds in salt water. When I use the SS BP/W in Salt water with a 3 mil on (no heavy sta) I wear 2-4 pounds but could probably go without it. Just some scenarios for you.

Good luck!

 

[wunat]

You should be getting some good advices from previous posters.

Is your diving mainly in tropical water?

I did some research myself when I am deciding to switch to BP+Wing diving from a BC jacket, aluminum BP is recommended by many if one is mainly to dive in tropical water as less weight is required for the thin wetsuit required under such condition.

I have the aluminum BP for my setup and I still need to have extra weights even though I am in 0.5mm suits.

This might take away the your concerns on weights. Hope this helps.

But in any case, the previous posters might already provide you the answer.

 

[bketchel]

Can somebody help me understand the previous post? I though steel was heavier than Aluminum? Seems like the main advantage to using AL BP in tropical waters would be that it makes for lighter traveling, and the concern with Steel bp in tropical waters would be overweighting. Am I on.....or waaaaaay off?

 

[The Kraken]

BK,
The reason many people dive an aluminum back plate in tropical water is that the waters are considerable warmer therefore requiring less exposure protection (read as neoprene - flotation).
Thinner wet suits, and in some cases none at all, result in having to have less weight to overcome the inherent buoyant properties of the exposure suit.
The aluminum BP is worn to reduce the overall weight loading for the diver since the extra weight is not needed to get down.
Stainless steel may not render a specific diver overweighted in tropical waters. Some people are more inherently buoyant than others and may wish to use a SS B/P in lieu of extra weights.
It pretty much comes down to how one configures one's kit and what type of kit a diver prefers to dive.

 

[JeffG]

BK,
The reason many people dive an aluminum back plate in tropical water is that the waters are considerable warmer therefore requiring less exposure protection (read as neoprene - flotation).

It also weighs less..helping in the weight restrictions that Air Carriers have.

 

[RiverRat]

Can somebody help me understand the previous post? I though steel was heavier than Aluminum? Seems like the main advantage to using AL BP in tropical waters would be that it makes for lighter traveling, and the concern with Steel bp in tropical waters would be overweighting. Am I on.....or waaaaaay off?

I just went through all this not long ago. I originally started with a 9# SS backplate. In the tropics I need only 3# on my belt with an AL80. I weigh 230#. So if you were a 140# person that plate would overweight you slightly or you would just have NO ditchable weight. I prefer minimal ditchable weight 3# - 6# or so, maybe 10# max if needed.

I went diving for the first time in NC over the summer with my new steel tanks. As I was in a 3mm shortie like the tropics I knew I would be overweighted with steel tanks so I bought an AL backplate. I dove this rig with 4#. I also took this rig to Bimini with me as there was a 50# limit on the seaplane. I used 10# on my belt with an AL80 out there.

Do your homework first. If you get too heavy a plate you may have to buy another one. I don't mind so much as it give's me options as I dive in different environments.

 

[Wijbrandus]

I use a steel backplate. With a 3mm full wetsuit, I still strap on 10 or 12 pounds of lead in salt water. In fresh water, no wetsuit, I'm actually about 2 or 3 pounds too heavy, but I operate just fine anyway.

Dumping weights underwater is overrated and overemphasized in training. At least this has been what I've read and experienced. In a balanced recreational rig, you can easily swim up all your gear without ditching anything.

Travelling with the 6# plate is not a lot of fun, but very doable. My gear bag weighs a bit under 50# total, so the plate does make a difference somewhat. To be honest though, I ***** more about the regulators when travelling. I carry both mine and my wife's in my backpack, with a laptop. My backpack probably weighs close to 40# once this is in there with whatever I need on the plane (cd player, book).