Questions concerning Backplates.

[halocline]

If I get in and descend to 15', then get neutral to hang out and wait on the rest of my group to get in and ready to descend to 90', once the group is with me, are you saying that I should always, if I am correctly weighted, be able to descend from 15' to 90' with just breath control? Should I fin down? Or should I just exhale and dump a bit of air, IF necessary? I would say exhale and vent if needed, but danvolker's post says to fin down.

If you are neutral at 15 ft with some air in your BC, likely at the beginning of a dive, then yes you should be able to easily descend without venting any gas from your BC. Just put your head down, exhale, and get started. As soon as you're moving the air inside your BC will compress and you'll be displacing less water, making you more negative.

But again, many of these various "what-ifs" are readily answered through diving experience, which if your profile is correct, you don't have have much of yet. In very general terms, you will be adding air to your BC when you descend to control the rate of descent, and dumping as you ascend to do the same. AND, in very general terms, you'll be using your fins to propel you in whatever direction you want to go if necessary. It's really not that complicated.

 

[stuartv]

If you are neutral at 15 ft with some air in your BC, likely at the beginning of a dive, then yes you should be able to easily descend without venting any gas from your BC. Just put your head down, exhale, and get started. As soon as you're moving the air inside your BC will compress and you'll be displacing less water, making you more negative.

I understand that. That's what I would normally do. That's why I said vent IF necessary. With the IF in all caps, no less.

 

[Dhboner]

Hate to nitpick but if you are diving with a group you might want to wait at the surface and descend together ;-)

 

[stuartv]

Hate to nitpick but if you are diving with a group you might want to wait at the surface and descend together ;-)

That is what I have always (in my extensive 4 months of diving ) done. That scenario only occurred to me because I was taking a U-boat Diving class over the weekend. Most of the students were in the 200 and up category on number of dives. One of them was talking about diving off a boat in heavy chop (off NC) and talked about descending a bit to wait for the rest of the group.

---------- Post added March 30th, 2015 at 04:49 PM ----------

Oh, and that and discussion in class of hot drops was what put it in my mind that, even if one CAN descend only using breath control, the initial descent to depth would normally involve dumping all gas from the BC. So, even with a brief pause at 15', I would still think I would dump everything in my BC if I've got a long way to go and a short time to get there. (Watch ole Bandit ruuunnnn....)

 

[cool_hardware52]

Oh, and that and discussion in class of hot drops was what put it in my mind that, even if one CAN descend only using breath control, the initial descent to depth would normally involve dumping all gas from the BC. So, even with a brief pause at 15', I would still think I would dump everything in my BC if I've got a long way to go and a short time to get there. (Watch ole Bandit ruuunnnn....)

LOL, Your "hot drop" is going to feature a "pause" at 15 ft? Do you like sand dives?

Tobin

 

[ams511]

"Your understanding" I assume that means you've never actually tried to repair a single layer inflatable, but if course that doesn't prevent you from offering an opinion on such a repair.

Here is the reality. Single layer inflatable use a thin layer of urethane laminated to the *inside* surface of a woven textile. Smearing Aqua seal or similar moisture cured urethane adhesives on the *outside* textile surface may offer temporary repair, but is not a reliable long term solution. There are many threads on the Deco Stop concerning trying to access the *inside* of single layer wings via the OPV or fill fitting holes. Probably a few on SB too. The gas can get past the failure on the inner layer, travel sideways through the fabric and exit at a point beyond the original damage.

Love to see a list of wing / bc manufacturers that advocate such repairs. Look here to see Halcyon's position on repairs, which BTW I understand and agree with.Patching Inflatable Products | Halcyon

Smearing aquaseal on the fabric (outside) of an inflatable is like trying to fix a roof leak from inside the attic…..

Tobin

Lets go back to the original issue. Your statement that it should not be a stretch that your Torus wings do not use a zipper because bladderless wings do not use zippers. You seem to gloss over the fact that yours is the only wing on the market with an inner bladder that does not provide access to the bladder. Kind of like a car with the hood welded shut. Would you purchase a car that needed to be sent back to the factory for repair (even if it required no routine maintenance)?

Bladderless wings don't have zippers because there is nothing to repair inside. Your Halcyon link seems to support this point. Also to put a zipper on a bladderless design you would need a "dry zipper" to keep the air in and the water out. I am not in the dry suit business but my intuition would tell me that this is rather expensive. I am not a GUE/DIR/UTD trained diver but I would assume this zipper would be a potential failure point. I am not in the BC business but I assume these factors and the fact that there are better designs, such as a zippered wing with an inner bladder, conspire to keep bladderless zippered wings from the market.

As to repairing a bladderless design. Zeagle does sell a BC repair kit, so they think it can be done. Also from NESS:

2. Wing Punctures (Bladder Wings) This one can not be done at the dive site. You will need a BC Tool to remove the corrugated hose mounts on the wing. Make sure before you do this that your wing has a bladder some wings are bladderless if this is the case just jump to the Aquaseal step. You will have to dissemble the overpressure relief. Once this is all done, pull the bladder out and reassemble it. Now blow the wing up spray the wing with a bottle of water with a little dish detergent mixed in, this will help you find the leaks. Check carefully usually if the wing was pinched it has holes on both sides. Mark any holes with a permanent marker. Now deflate the bladder and lay it flat on a table. Get a scotchbrite pad and scuff up the area. Remember you are just scuffing it up do not go crazy. Once scuffed, just put a dab of Aquaseal on it. If you do not know what Aquaseal is, shame on you what kind of diver are you! After this is done and the wing has dried for 24 hours inflate it and check for leaks again. If you do not have any reassemble the wing.

Does this mean John doesn't know what he is talking about?

I never needed to patch a bladderless BC, however an old dive buddy of mine used to dive a patched Parkway BC. A dive shop patched it an the repair lasted at least 5 years and a couple of hundred dives. So these repairs can last. There are many divers that successfully patched bladderless BCs. I am sure there are many that unsuccessfully patched bladderless BCs.

However the question is why design a wing with no access to the inner bladder? Looking at the your wing line-up I get the impression that you are either unwilling or unable to sew a 360 degree zipper for the shell.

 

[cool_hardware52]

I never needed to patch a bladderless BC, however an old dive buddy of mine used to dive a patched Parkway BC. A dive shop patched it an the repair lasted at least 5 years and a couple of hundred dives. So these repairs can last. There are many divers that successfully patched bladderless BCs. I am sure there are many that unsuccessfully patched bladderless BCs.

I've welded up cracked cylinder heads that are still running, doesn't make it a good practice. Apparently I was exactly correct when I assumed you personally have never used aquaseal to repair a single layer wing.

I've tried it myself and found the failure rate unacceptable. I've also seen the repairs that others have attempted, some seemed ok and others failed.

However the question is why design a wing with no access to the inner bladder? Looking at the your wing line-up I get the impression that you are either unwilling or unable to sew a 360 degree zipper for the shell.

I guess I'll need to issue a Press release monthly on this very issue. I've answered this question many many times before.

Please pay attention:

1) Our wings with 30 mil bladders and 1050 shells seldom suffer bladder problems, it happens but it's pretty rare.

2) Our quick removal system further reduces the incidence of bladder damage.

3) Most divers and most dive shops don't work on any BC's if the manufacture is willing and able to do so at a fair price and fast turn around. We turn most repairs in 24 hours. We get pretty much equal numbers of zippered and zipperless wings returned for bladder replacement etc. Apparently most divers want a professional to install the bladder and test the entire assembly.

4) 360 Zippers make wings bulkier for travel.

5) If your primary concern is bladder access we offer a line of LCD wings with zippers.

6) If you really believe that only a donut wing will meet your diving needs and you expect to beat on your gear there are other brands to choose from, have at it.

Perhaps you can bookmark this post for use when you feel the need to ask this same question *again*

BTW, we sell more Torus 26 wings than any other style, apparently our actual customers appreciate the design.

Tobin

 

[Eric Sedletzky]

I just read the first post again to see what the actual thread is about.
To answer the OP's question, no, IMO it doesn't matter if a S/S plate is 304 or 316 for most practical purposes.
I suppose someone like a career DM working on a charter boat that has their rig bungeed to a holder out on the dive deck 24/7 and exposed to the elements like a lot of dripping salt air all the time then a plate made from 316 might make sense. But for the majority of divers who rinse and put away their gear I don't think it makes a hill of beans of difference.
My last batch of plates I was talked into using 316 which 'seemed' to tool a little better and 'seemed' a little softer to shape but it actually was a PITA because 316 is usually special order, it's more money, all the other stuff I need like rail rods, channel stock, etc then also needs to be 316, the tig rod needs to be 316, so it's a pain.
I'm going to go back to 304 for my next time around.
I'm also in the marine business and use a lot of stainless to make boat railings, stanchions, fittings, etc.
On boats everything topside for heavy marine exposure is made out of 316, but believe it or not everything underwater is made from 304.
The 304 is stronger so for prop shafts, rudders, rudder shafts, trim tabs, and anything else that lives below the water line they recommend 304, but it has to be properly zincked. Even plain steel will survive underwater properly zincked but topside it of course get eaten up in no time.
Oxygen is the key factor.

So, to jump into the ring for our exciting little tag team match (where this thread ended up)
My philosophy is, in warm water if you are overweighted at all to where you need any air in your BC/wing to stay on the surface then you will be constantly adding and dumping air the entire dive.
If I am wearing nothing but swim trunks and have nothing on me that has any inherent buoyancy then there is nothing that will crush at depth, therefore there is no reason to add any air to a BC/wing to counter loss of buoyancy. In this situation I could dive with no BC and be just as neutral at 100 feet as I am at 20 feet. However if I put say 5 extra lbs on a belt and then make up for it by putting just a little air in my BC/wing to stay afloat on the surface, then every ATM I descend I will have to constantly make up for that little bubble that gets squeezed down the deeper I go and I'll have to maintain that same volume. So at 4 ATM's I have to put 4 times the amount of air into that wing just because I had a little at the surface. Overweight yourself even more which equals more air at the surface in the wing and it just compounds worse the deeper you go. So just for the luxury of being able to descend feet first and elevator diver will have to constantly manage air in their BC depending on depth. Remove the unneeded weight and very little to no air needed.\
So with this whole BC thing, in so many cases I see this whole circus go on with BC's that in warm water doesn't really even have to be there. Something that was invented to counter the heaviness of suits which BTW was a complete luxury at one time, has now become this whole drama and the centerpiece controversy it seems.

Now, add a 3mm shorty, there is a little inherent buoyancy but not a lot. The amount of buoyancy a 3 mil shorty presents is probably only a few lbs and can easily be made up by lung volume. Add a 3mm full suit and it's trickier but a person could use no BC if they wanted.
Figure also that the greatest pressure changes are in the first 30 feet, beyond that the pressure changes are less every ATM you go down so if you can get your weight dialed in in the 30 foot area you can use lung volume to make up slight changes deeper.
Now, add a 4 or 5 mil and if you want to go deep you might begin to need a wing.
Dive a 7mm and most people wouldn't dream of not using a wing, but with the suit I use I can go to about 40 to 50 feet with no BC, beyond that I like a wing.

With up and down currents.
OK, so take the above info and lets apply it to an up or down current scenario. What's the first thing they teach you to do if you get into a run away ascent? To flare right?.. So if you are flat with your wing inflated and experience a down current and you decide that in order to counter the down current you need to inflate your wing, well, what you're doing is basically catching as much water as possible (just like flaring) but in reverse, and to compound the problem you're expanding your wing to make an even bigger surface for the water to push on (like a sail on a sailboat). A better solution is to keep your wing to a minimum with air through proper weighting (if it's warm water then no air, or in my case no BC), and make the smallest 'hole' through the water that you can by pointing your body into the direction the water is coming from and use your fins to propel yourself out of the situation. Just like going fast through still water, the best way is to find the ultimate 'slipstream' to take advantage of the least amount of drag. The difference here being the water is the thing moving not you. Forget about air usage at this point, the objective is to get out of harms way so use as much gas as you need to make it happen. Just like passing a car, don't screw around trying to save gas by not flooring it, just floor it and get around the guy. Keeping in shape helps, the right fins also help. All this stuff goes hand in hand and is part of the bigger picture. This is also the basis for minimalist diving which is the belief that less gear and more skill are safer than more gear and less skill.

 

[boulderjohn]

I'm definitely a bit confused now. I thought I had learned that I should, essentially, try to avoid finning as much as possible, to conserve air. So, my first instinct for going up or down would almost always be, one, use breath control, then, two, use my BC, then, last, fin myself if the first two weren't enough. Why burn the air to fin against a vertical (up or down) current, when you can use some combo of breathing and BC to do it?

I don't know any instructor who would tell a student diver to inflate the BCD to ascend.

If you are neutrally buoyant, a good inhalation or a few lazy kicks should get you going up. When you do, the air in the wing will start to expand, so you will eventually have to dump air to avoid the rocket ride to the surface. Many students get confused when they are taught skills in the deep end of the pool while negatively buoyant and kneeling on the bottom. In that case, the instructor may have the students infate BCDs enough to get neutrally buoyant, as they should have been if diving and not doing skills kneeling on the floor, and then begin the ascent. If you learn through PADI, you are supposed to be taught to use the 5 point ascent method, which includes finning as you ascend and dumping air as you become buoyant.

 

[tridacna]

I was sitiing next to a cute blonde about to splash at the Blue Hole in Belize when she showed me her inflator and asked:"Which button do I press to go up?".