Too much lift?

[cool_hardware52]

I'm sorry that position seems to piss a rather few people off. It shouldn't. They have their own agendas. .

Once again, assigning motives. SMH.

Me? I make every attempt to educate my customers about how to determine required lift. I spend hours every week doing so.

A standard part of nearly every discussion I have with potential customers to clearly define the circumstances under which a particular gear recommendation is no longer valid, for example when a small warm water BC would be inadequate for use with more buoyant BC's.

To continue to claim I favor BC capacity well matched to the application is based on need to sell gear in the absence of education is simply untrue. You have yet to provide a single example.

Again, produce for me any customer that will report I 1) Sold them more gear then they needed, 2) Failed to educate them about why I made a particular recommendation, and when that recommendation was no longer valid.

I've declined many sales when I thought the user didn't fully understand the safe window for use, but I've never ever tried to sell people more gear than they actually needed.

Tobin

 

[The Chairman]

Once again, assigning motives. SMH.

What motive was assigned, Tobin? You keep saying that and I haven't assigned a thing. Unless pointing out simple facts is pointing out a motive.

To continue to claim I favor BC capacity well matched to the application is based on need to sell gear in the absence of education is simply untrue. You have yet to provide a single example.

I have never claimed that. You have stated several times that Large BCs are the root cause of overweighting. I am claiming that this is throwing gear at the real problem.

Me? I make every attempt to educate my customers

About your gear. There's nothing wrong with that, but your goal is to recommend your wing in the size you deem right. How many times have you sent these customers to OxyChek? To Hollis? To Dive Rite? Your solution is a particular wing size and if your customer doesn't agree with you, then you send them packing. In that regard, you do send them to these other manufacturers. But I'm going to bet that you recommend your wing first.

My MO, is to show students how to dive with the least amount of air possible. It makes it easier to manage the bubble that is there in regards to both how the bubble changes in regard to Boyles Law as well as shifting the diver's center of buoyancy. It really doesn't matter what size of BC you have, but the amount of air you put in it.

 

[RayfromTX]

I am a recent customer of Tobin and Deep Sea Supply. As a new diver I found my conversations with him to be very informative. I will admit I felt insulted at some point in each conversation. I definitely had to let him lead the conversation and just try to listen carefully. He always said he had no time for the conversation and then took all the time we needed for me to thoroughly understand every concept he insists his customers understand. It was exhausting yet enlightening. In my opinion he is a lousy salesman and a good educator and a great gear designer/manufacturer.

I will say with no uncertain terms that I trust the man and his motives. I will buy from him again and I will recommend him to others. I think he should back off a bit from making claims about large wings allowing people to be over-weighted even if that is true. It starts arguments that become focused on personalities and motives instead of educating new divers which is the primary motive of Tobin and Pete. To think otherwise would be to ignore years and years of refusing to let people here and elsewhere be ignorant about these gear issues. I see them both in action and neither man sets off my cynical radar. Thanks to both of you for your commitment to making good divers. It is a rough environment currently to pull that off and make a living at it.

Oh and if you call Tobin wanting him to sell you one rig that you can take to Cozumel or dive doubles in a drysuit he is going to sell you two rigs as he should. That is in no way because he wants to take two whacks at your wallet. It's because he would feel like a shyster to pretend that he was doing you a favor by selling you one rig and pretending it could actually work well for both.

Having said all that and defended the man, I am sure that he next time I call him to get a BP/W for my wife I will probably end the call feeling like I've been talked to like a small child.

Each of you feel like part of my dive family and I am grateful for what I have learned from both of you.

 

[Centrals]

I've declined many sales when I thought the user didn't fully understand the safe window for use, but I've never ever tried to sell people more gear than they actually needed.

I am NEVER involved in scuba business but was in retail(kind of) before retiring not too long ago.
I have the same philosophy but sometimes I could feel the resentment from the clients!!! Some of them would never accept even a superior suggestion, to suggest anything different seemed to inflict ultimate insult to their intelligence. My staff would just sell anything they wanted and glad to see them off the office.

 

[REVAN]

Real question here is, what is average speed used to calculate your 40% increase? I am not saying your results are wrong, but if I want to prove a point I can choose a speed that would be 10% or 100% increase. At last, I got the picture, when I dive I don't race.

The constant was the pull force. I used 20 pounds because it was both representative of cruising conditions (i.e. - it's easy to produce 20 pounds of thrust with fins), and 20 pounds seemed to be about the easiest value for the person pulling to pull consistently with the least amount of variance during the test. With force being the constant, speed will then vary until the resulting drag equals 20 pounds. The drag coefficient is a normalized and dimensionless constant that has the speed content removed so that the comparisons will be meaningful and transferable to different speeds. The coefficient will generally be fairly consistent over different speeds, although low Reynolds Number conditions can affect the coefficient values for certain shapes.

 

[NAM001]

I've seen several references to large wings recently, in the context of back inflate BC's (though I believe this question applies to a BP/W setup as well). Most of my diving is vacation/tropical, though I live in chilly New England so local ocean diving is a possibility. I'm a new diver, but I think I understand the differing lift requirements for cold vs. warm water diving. 20lbs of lift would be more than adequate for my warm water diving but I'd need more for local diving.

A one size fits all solution would be ideal. Bungied wing setups like the Zeagle Stilleto or ScubaPro Hydros Pro would fit the bill for a warm water travelable BC with adequate lift for most cold water diving as well. But, I've seen the criticisms of setups like this - too large a bladder/wing, too much lift, etc. Even BP/W owners refer to having multiple wings...

Is it unrealistic to think that one setup could work well for recreational single tank diving in both warm and cold water?

No it is not unrealistic. You have to look at the worst scenareo and have a wing that will cover it. IE full tank properly wighted with your thickest wet say 7 mil full suit on and going to 100 ft. how heavy are you. Lets say your suit at 20 ft has 20# lift and your full tank rig is -8# you need about 22# lead to be neutral at 20 ft. you goto 100 ft and you loose 18# oof the suit lift adn you are that heavy pluss the tanks air weight of 6# so that will need a wing of 26# lift to hold you neutral at 100 ft with full tank. at 20 ft at safety stop you regain the lift from the wet suit and all is well. Most use a 27-32 lift wing for a single tank for heavier suits. If you had a 40# single wing you sould have problems with air expansion and ascelerated ascent rate. a smaller wing ansd the relief would lift and vent with out increasing the lift from the expanding air in the wing. The smaller the wing the less air that can move from your hips to your shoulder making trim stableization better. I dive warm water and use a 2-3 mill shorty i need a lot less minimum wing capacity untill i dive with no suit and because i use no weights i am heavy with no weights to remove. solution to that would be to change to a al plate. idive a steel BPW and steel lp tanks so my 30# wing is still good for that configuration. also remember it takes about 10# of lift to hold you head out of the water. If yo want to have some reserve in case you buddy blows a wing then you need a larger one. A lot of factors go into properly sizing a wing.

 

[Nasser]

From observations over the years I've noticed that divers who are overweighted, more often than not, tend to have a host of other bad habits as well. Lousy trim, poor situational awareness, standing on the choral, etc.. This leads me to believe that these bad habits - including being overweighted - are more a result of poor training rather than having an oversized BCD (actually an oversized BCD/Wing is a result of poor knowledge).

I think it's safe to say that the vast majority of sport divers are diving jacket style BCD's. When I started out and went equipment shopping, first and formost I wanted a jacket BCD that fit. I also considered the color, look, number of pockets, D rings etc. The notion of lift was something I didn't really consider - as it was assumed that was "embedded" into the size of the BCD by the manufacturer. It is only recently, meaning the past 10 years or so that I've seen an increase of BP & W for single tank sport divers, and they're still the minority... and even less so for newly certified divers looking to purchase equipment for the first time.

So perhaps in the beginning, the BCD design also has something to do with it. Choosing the appropriate size and lift capacity is more obvious when you need to make that decision with a wing.

Does an oversized wing encourage overweighting? perhaps, but I'm more inclined to think that a lot of overweighting issues are due to ignorance and poor instruction - and that can also come as a whole package with a bunch of other not so great habits.

 

[admikar]

Someone mentioned that smaller wing packs better. Did anyone measure difference in size of packed 17-20# wing vs. 30# wing from same manufacturer?
@cool_hardware52 helped me when I tried to choose my BP&W, not with any specific numbers, but with an explanation of required lift for any gear configuration, that was easy to understand, thanks for that.
In ideal situation, diver would have correct lift BC for any configuration he/she dives. In real world, people usually make compromises. In my case I went with SS plate, 30# wing and it works for both my wetsuit and drysuit config. Could I use smaller wing for my wetsuit? Yes, but I am happy with how it works for now

 

[ronscuba]

DSS shows the dimensions of all their wings on their site if you want to compare.

Deep Sea Supply -Backplates & Wings-SMB-HoseHat_Single tank & doubles Tank Scuba rigs_

 

[The Chairman]

From observations over the years I've noticed that divers who are overweighted, more often than not, tend to have a host of other bad habits as well. Lousy trim, poor situational awareness, standing on the choral, etc..

I agree. Until you get your trim flat, neutral buoyancy will always be an issue. As long as you're having an issue staying neutral, your situational awareness will always be compromised.