Why does an LDS push newbies away from BP/WINGS?

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MikeFerrara once bubbled...
I'll take your word that you solve trim problems with ankle weights but I've trimmed out hundreds of divers (students) and have never used a single ankle weight.

Actually, I have no need for ankle weights - - you misread what I wrote.

My point was that if "everyone" in Jackets were always nose-high, ankle weights makes that type of trim problem worse, not better...and since ankle weights exist, that means that a lot of people are nose-down (feet high): this is the opposite of the condition that you claim is the common problem.

Around here just about every one with a 1/4 inch suit and 20 pounds or more on the waste is severely head up in the water and they go totally vertical when they stop foreward motion.

I don't dive locally here (off NJ) all that often, but I've not seen that as a common occurrence at all. Maybe I've been lucky to avoid the novice & dive class boats? Overall, I see more trim problems in warmwater, with most of these being the fundimental mistake of not adding enough air to his BC to actually be neutrally buoyant, so they swim along at 45 degrees...this has nothing to do with what kind of gear they're wearing.


-hh

 

[MikeFerrara]

-hh once bubbled...


Actually, I have no need for ankle weights - - you misread what I wrote.

My point was that if "everyone" in Jackets were always nose-high, ankle weights makes that type of trim problem worse, not better...and since ankle weights exist, that means that a lot of people are nose-down (feet high): this is the opposite of the condition that you claim is the common problem.

I guess I misread.

There are those who are floaty on the other end but also ankle weights are often used with dry suits by people who put too much air in or who's suit doesn't fit. In Scuba, you can't assume that because a thing is made there is a valid use for it. You can only conclude that some one is able to sell it.

I don't dive locally here (off NJ) all that often, but I've not seen that as a common occurrence at all. Maybe I've been lucky to avoid the novice & dive class boats? Overall, I see more trim problems in warmwater, with most of these being the fundimental mistake of not adding enough air to his BC to actually be neutrally buoyant, so they swim along at 45 degrees...this has nothing to do with what kind of gear they're wearing.


-hh

It's a "what came firs the chicken or the egg" kind of thing.

All divers who have head up trim are negative and sink when they stop kicking. Now, part of it could be that they just don't get neutral. However, often the problem is the head up trim itself. In order to move foreward without swimming to the surface they must be negative because their feet are pointing down thrusting them up. So...they start to move and go up until they dump. Now their foreward motion combined with the upward thrust is holding them up. Now if they stop they sink, add air, or just go vertical and kick.

It's more noticable in cold water with heavy suits but you see it in warm water too if you know what to look for. It's more noticable with a heavy suit because as the suit compresses with depth, more air is added to the bc. the buoyancy is shifted from where the suit was to where the bladder is. If the weight and the new center of buoyancy aren't balanced you get thar torque. The more suit you have and the deeper you go the worse it gets.

A bp/wing, IMO, is easier to get balanced but isn't an automatic cure.

 

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grunzster once bubbled...
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just curious, have you ever even dove a back inflate or BP? I'm not trying to be a D**K, but it really just sounds like you have very little experience with them.

Yes (including 30+ dives within the past ~6 months). More importantly, over the years, I've dived with all three basic types of BC's...the third type being the horsecollar, back in the '70s and before the power inflator was even invented.

I also don't mean to be a jerk when I say this, but while IMO the BP is the right choice for diving doubles, this 'fact' does not automatically also make it the right choice for diving with singles.

Keep in mind that back inflation existed years ago for single tank appliations, and that it died out nearly completely until just a few years ago with the "Tek rush". Why? Well, to me, it has every sign of being yet another DEMA Bandwagon snake oil fad product. Maybe I'm wrong, but from what I've seen happen in the dive industry over the past 25+ years, I doubt it.


The real bottom line is that all BC designs have trade-offs, and while I'm currently diving with a back-inflate, I really don't like it at all with a single AL80 because of its lack of what I consider to be adequate surface stability.

YMMV on what constites "adequate" and so forth, but I tend to become particularly cranky after I've been floating on the surface for a fraction of an hour after a dive wondering where the Blessed Mary the bloody pickup boat wandered off to...

I'm still very much a rookie. My OW dives and the few right after my cert were with a jacket. Hated it! My buddy also a newbie, same thing. When we stopped, we were just like Mike described, VERTICAL BIG TIME.

I'm not saying that it never happens: what I'm saying is that if we accept the premise that its OK to adjust one system to be adjusted to minimize a problem, we have to allow all systems the same level of effort of adjustment to minimize their weaknesses if our objective is a fair and honest, objective evalaution.

I've never had any problem, with face down at the surface. Just lean back and ride it like a little raft. And when I say lean, I mean with very little effort. It's so comfortable, I could almost take a nap while I'm floating there.

While we can roll onto our back, because this is a dynamically unstable configuration, it takes a discrete effort to maintain this position, and is quite fatiguing in choppy/rough seas. Perhaps you've not had to try to hold such a position for a half hour yet.

And while face down is never the problem, you don't want to be face down when you're trying to spot the pickup boat, keep the rocks in sight so as to stay off them, yell at your buddy to get the heck away from the rocks himself, etc, etc. Because of the mass of the gear we wear, even a simple near-shore 2ft chop will tend to break over our heads...its a good idea to see it coming.

Overall, *all* efforts lead to fatigue, which hurts your long-term survivability if you have the bad luck to get lost by the boat for even a few hours, let alone overnight. Personally, I don't want to dive a rig whose surface characteristics functionally guarentees a level of effort that means my death on an overnight float, but that's your perrogative.

FWIW, in my case, I'm carrying an UW camera in my hands, and this forward mass exasperates the BB's front-rolling tendency. Because of this, I'm very seriously thinking about going back to a Jacket (I don't want to add a band-aid like the Halycon liferaft).

I don't know anyone else who's had a problem with that, and on this board every post I've ever seen with that concern was from someone who had only dove jacket BCs to that point.

In addition to the Placebo effect, basic human pychology is that admitting making a mistake on a purchase is rare. For an interesting example, check out _Consumer Reports_ magazine's annual automobile issue: the percentage of people who report that they would buy the same car again is always over 90%, including the models that are obvious lemons.


-hh

 

[MikeFerrara]

In my 6 pound stainless back plate and a Halcyon 27 or 36 pound wing, a singl al 80, a two piece 1/4 inch farmer john, 4 pounds on a weight belt and 4 pounds on the upper cam band I am trimmed well in the water and I can stay VERTICAL at the surface with no more effort than with a jacket.

I don't get pushed on my face. I don't have to lean back
There is no danger in rough seas or any other such silly nonsense.

This rig is so stable and slips through the water such that I couldn't even imagine myself diving any other way ever again.

If you get pushed on your face something fundimental isn't right.

 

[MikeFerrara]

-hh once bubbled...






In addition to the Placebo effect, basic human pychology is that admitting making a mistake on a purchase is rare. For an interesting example, check out _Consumer Reports_ magazine's annual automobile issue: the percentage of people who report that they would buy the same car again is always over 90%, including the models that are obvious lemons.


-hh

No way, I could fill a fair size truck with gear I bought that was a mistake. I didn't know any better but now I do.

 

[grouchyturtle]

Ok you have a point. I've never used it in really choppy conditions. Have done some pretty long surface swims with it though.

But also as Mike said I really don't feel the rig pushing me forward. It really takes very little effort to be vertical on the surface, I can't imagine it being much harder in choppy water.

The only time it pushes me forward is if I'm overinflated on the surface. Dump some air and then it's no problem.

Wow you only wear 8lbs. in a 2 piece with an AL80?

 

[MikeFerrara]

grunzster once bubbled...
Wow you only wear 8lbs. in a 2 piece with an AL80?

Don't forget the 6 pound plate. That's 14 pounds.

 

[Rick Murchison]

ClassAction once bubbled...
Why does an LDS push newbies away from BP/WINGS?

Around here, most newbies intend to buy their own basic kit but no tanks, and intend to dive nothing but AL 80's (or AL 72's in the Caymans) in warm water with a lightweight wetsuit, and likely take pictures on vacation in the Caribbean. For that kind of diving, a jacket provides better overall performance and convenience, much better surface floatation characteristics, packs smaller and is more comfortable. And so, for them I recommend a jacket style BC.
Rick

 

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MikeFerrara once bubbled...

Don't forget the 6 pound plate. That's 14 pounds.

For a 1/4", a worn-out wetsuit is probably contributing too:

For my Galapagos trip last fall, I picked up a new 1/4" Farmer John last year and it took 14lbs to sink each half (28lbs total) in the diveshop's freshwater pool. After a couple of dives to 100+fsw, the required weighting drops by 5-6lbs.

If you get pushed on your face something fundimental isn't right.

I agree. And in going down to first principles, it pretty much has to be the BC's bladder location. This was primarily to be a travel rig, so using a weighted SS plate isn't an option. Most of the dives I've done to date have been warmwater, which has allowed me to already locate all of the weights to completely behind me. That helped but it wasn't as stable as I'd like it to be. Raising the tank didn't help much. About the only options left to try are to get a new BC or to get rid of the UW camera (which in reality is not an option). One thing that I do want to try next time out is to carry a ~5ft tether for the camera so that I can clip it off to have it hang it directly under me while I sit on the surface to see if that makes a meaningful difference...not that I'll be able to recover to the boat this way, but just as an experiment.


-hh

 

[MikeFerrara]

-hh once bubbled...


For a 1/4", a worn-out wetsuit is probably contributing too:

For my Galapagos trip last fall, I picked up a new 1/4" Farmer John last year and it took 14lbs to sink each half (28lbs total) in the diveshop's freshwater pool. After a couple of dives to 100+fsw, the required weighting drops by 5-6lbs.




I agree. And in going down to first principles, it pretty much has to be the BC's bladder location. This was primarily to be a travel rig, so using a weighted SS plate isn't an option. Most of the dives I've done to date have been warmwater, which has allowed me to already locate all of the weights to completely behind me. That helped but it wasn't as stable as I'd like it to be. Raising the tank didn't help much. About the only options left to try are to get a new BC or to get rid of the UW camera (which in reality is not an option). One thing that I do want to try next time out is to carry a ~5ft tether for the camera so that I can clip it off to have it hang it directly under me while I sit on the surface to see if that makes a meaningful difference...not that I'll be able to recover to the boat this way, but just as an experiment.


-hh

the only thing I don't understand is if all the weight is behind you and you're body/suit is (buoyant?) then why would the wing push you foreward? Is it the weight of the camera? You're experiment might be worth doing.

Just for reference, when my doubles are full, I'm pulled backwards because all the weight is in the tanks (behind the wing).

Not to be stating the obvious but another thing to watch for is if the bc has a tendancy to ride up on the diver that too will push the diver foreward especially if more air is added to compensate for not getting up in the water.