Questions concerning Backplates.

[halocline]

I've been in down currents on a wall, swimming hard and laying on the inflator button just to avoid descending. It can be fairly scary, and in a place like Cozumel it is not uncommon in some areas. I think once you're in a strong current you do whatever you have to. I've heard swimming away from the wall can help, but the 'natural' tendency is going to be to swim to the wall to grab on to something. I don't think up currents are as common but I certainly have heard of them.

Not sure what this has to do with a right-side dump, though. If you have that much air in your BC at depth, even dumping from one side will certainly do the job.

This is the problem with 'what-ifs' like this. Okay, sure, in an online discussion group you could make the argument that in this specific scenario, theoretically it could be useful to have an extra dump, but if you put one on the wing, you're worse off in other ways and you're stuck with it. The old dive rite travel wings used to have a right side dump and it was in a pain in the ass (well, right cheek anyway, haha) because once you learn to vent with your left hand only it's MUCH more convenient to reach down to the left hip. It's muscle memory. As far as having dumps on both sides, it definitely is an extra failure point and something to snag on. Those OPVs, even the good ones, are not the most bomb-proof valves.

 

[stuartv]

fin power is much easier to regulate speed up or down with....but----if fin power is not enough, then the BC may be required in such an unlikely emergency scenario

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?

 

[cool_hardware52]

Many newer divers tend to view every problem as having an equipment solution. (If this wasn't the case SpareAire would have gone away years ago.)

Situational awareness and good technique takes time, but gear represents an instant answer to the newer diver.

One need only look at the very basic BC's true exploration divers typically use to understand that less does become more with experience.

Tobin

 

[danvolker]

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?

Clearly you learned from a different mindset than I did.... I tolerate BC's or wings, and use them ONLY for getting dead flat neutral once I reach the depth I want to remain at for a time....any sudden deviation up or down, is going to be from fins, as it is precise, immediate, and the right tool for the job.

The ONLY places I would consider use of the wing for ascent and descent, is in "some" caves with tight passageways and lots of silt potential, or similar surrounding in a passageway inside a shipwreck in an extreme technical penetration.....Both of these are way outside the experiences or interests of 99% of the divers in the world ( or SB) , and both are BAD techniques for use in open ocean around reefs nd walls.

 

[halocline]

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.

What you should have learned was to avoid unnecessary finning, like finning to stay still or finning to keep from sinking instead of actually getting neutral. Both of these are common new-diver mistakes. But if you actually want to, you know, go somewhere underwater, you need to use your fins. And don't forget, filling and dumping your BC uses air as well. You do understand that, don't you?

 

[cool_hardware52]

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?

It's not uncommon for me to start a dive negative by 20-25 lbs or more because we start with a *lot* of gas. I do definitely add gas to both my BC and drysuit as I descend, otherwise you can't slow down the freight train when you get to depth, and your drysuit will squeeze painfully.

Same thing on ascents without scooters, or if we have locked off the scooters. If the dive went as planned I'm leaving the bottom with a great deal of the gas I started with. Swimming up 15+ lbs and holding 10 ft stops is a chore. I typically initiate an upward move by inhaling until I just start to rise and then exhale and then vent a bit of gas from my wing and or drysuit. If I'm still using my scooter during the ascent (ascents into current in the open ocean get old fast and one does want to keep the anchor line in sight because the boat is at the top end of the anchor line) I'll often just tap the scooter up a bit to start the move to the next stop. Either way I need vent a bit to stop 10 ft higher.

OTOH if I'm in a 3mm wetsuit and single al 80 I'm never going to be more than a few lbs negative, maybe -4 lbs at the start. I won't need much gas in my wing during any portion of the dive, and as the weight of the gas in the tank drops I'll reach a point where there is little to no gas in my wing. If there is a small bubble in my wing 1) I can easily swim it down, and of course as I descend that bubble gets smaller, 2) My lung volume is often greater than the volume of gas in my wing, allowing me to make buoyancy adjustments on breath alone.

This is exactly why I stress using no more ballast than necessary. Being over weighted means a bigger bubble in your wing and requires adding or venting more gas than a properly weighted diver. If you take the GoodYear Blimp and hang a freight train under it you will need to add and and vent huge volumes of gas for every 1 ft of depth change. That sucks.

It's well to remember that in the early days of scuba there were no bc's. With careful weighting and modest gas volumes, typically 72 cuft or less, (and some experience) divers did just fine.

Tobin

 

[ams511]

You've got it bad for Tobin.

It had to have been over 5 years since DSS used thin bladders; based on the first wings I purchased.
If the flaw you are finding is to cite thin bladders; you are really reaching..... to back in the day!

These back plate and wing threads never fail to entertain.:cool2:

You REALLY have to dig hard to find fault with a complete rig that costs $460.

Cheers,
Mitch

Sorry Mitch but I have nothing against Tobin. My problems are with cheerleaders that say this brand is the greatest when in my experience is that it is not. I have/had wings from Halcyon, DSS, Oxycheq, Apeks, UTD, Hollis, Hog, Zeagle and DRIS. I believe I can make an educated opinion based on my experience.

 

[stuartv]

What you should have learned was to avoid unnecessary finning, like finning to stay still or finning to keep from sinking instead of actually getting neutral. Both of these are common new-diver mistakes. But if you actually want to, you know, go somewhere underwater, you need to use your fins. And don't forget, filling and dumping your BC uses air as well. You do understand that, don't you?

Yes, it sounds like we are in agreement that "going somewhere" does not fall into finning that one would normally be able to "avoid when possible". Going up or down, though, does not normally require finning. Breath control usually takes care of it, for me. After that, help from my BC (for me). I mean, if I can't go up or down to where I want just using breath control, then I generally figure I am definitely too positive or negative, as the case may be, and a little squirt or a little venting seems to be in order.

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.

 

[cool_hardware52]

Yes, it sounds like we are in agreement that "going somewhere" does not fall into finning that one would normally be able to "avoid when possible". Going up or down, though, does not normally require finning. Breath control usually takes care of it, for me. After that, help from my BC (for me). I mean, if I can't go up or down to where I want just using breath control, then I generally figure I am definitely too positive or negative, as the case may be, and a little squirt or a little venting seems to be in order.

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.

I'd exhale and fin down. If you were truly neutral @ 15 ft all you need is the slightest drop in depth to get started. Why dump gas and immediately have to add gas as you go deeper?

Tobin

 

[danvolker]

Yes, it sounds like we are in agreement that "going somewhere" does not fall into finning that one would normally be able to "avoid when possible". Going up or down, though, does not normally require finning. Breath control usually takes care of it, for me. After that, help from my BC (for me). I mean, if I can't go up or down to where I want just using breath control, then I generally figure I am definitely too positive or negative, as the case may be, and a little squirt or a little venting seems to be in order.

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.

My typical descent speed is over 100 feet per minute, sometimes over 200 feet per minute if I am coming down on a wreck in a current, and doing a hot drop---Captain says, "dan, would you like to drop on the wheel house of the wreck--I say yes....when the dive command is given, the captain drops me knowing how far from the wreck she needs to be for my descent speed--or if the boat can be directly over one end of the wreck". With a stiff current, I will use up much less air than a diver pulling down on a line--something I very rarely will agree to do...With a good captain, and vis over 25 feet ( ours is usually over 60 feet on our wrecks), there is no situation and no depth where I am pulling down a line ! Point here, is that a BC will not get the job done for a precise drop in current--not unless you are ridiculously over weighted--and I want to be almost neutral at the bottom with zero air in the wing....a couple pounds negative is ok.

[video]https://youtu.be/PIaXVw61qJI[/video]

In this video of the Wreck of the Castor, you can see that to interact with the goliaths, my ascents and descents during the dive, which are constant--as needed to follow the fish, need to happen immediately, and to be precise--and having a big bubble in the wing would make this a nightmare. This wreck is about 115 feet deep, Sandra, Bill Mee and I hot drop it, this normally taking less than 30 seconds to reach the deck or sand bottom in front of the bow--depending on the first shots I want. A BC cant do this. When I begin getting close to the bottom, I blast some puffs of air into the wing, and flair horizontal, find dead neutral, and I wear a suit that does not change lift needs much, so that I only have a tiny air bubble ---which I can pretty much ignore during much of the filming...Whenever I get to stop and look around, or slow down and decide what is next, I perfect dead neutral again.....but swimming gets the dive done...along with not ever using a buoyant suit.

The line you see is for the return to the surface, as some divers like to hang on it...I don't usually....I just swim in position.