Warped Dive World Evolution - BP/W Subgroup Mindset

[fire_diver]

I can't recall the last time I read anyone claiming DRAG as a reason to move into a BP/W. The advantages of the BP system is that:

it is streamlined
it has nothing on it the user doesn't need or want.
it can be customized as much as the user desires
it reduces inherent bouyancy of jacket BCs, sometimes by pounds. This means less lead needed to be carried.
cost - if a single item of a BP system fails, it can be replaced cheaply. When component of jackets fail, it can be expensive (or impossible) to replace and could result in throwing the jacket away.

If you don't want to use a BP, thats your choice. Why must you constantly try to start fights about them?

 

[Crush]

Why must you constantly try to start fights about them?

If by "you" you mean me, I don't start fights about BP&W. I may take issue with unexamined points of view, misconceptions and biases, but I have absolutely nothing against BP&W.

We'll talk about BCs adding "pounds" of lift later on...

 

[danvolker]

My response is a re-post from http://www.scubaboard.com/forums/5534842-post93.html:

There is (as usual) a lot of bitching about BCs and drag. People spout off a lot but can't back up what they say. Let's divide this lack of proof into two categories: (1) what can be proven or demonstrated empirically, universally, and reproducibly; and (2) what is necessarily subjective.

My statement that there is a lot of bitching falls into category 2 - my statement is subjective. In truth, I should have typed "to me it seems as though there is a lot of bitching about BCs and drag." Enough said.

Enter into the first category statements on BCs and drag. I posted here: http://www.scubaboard.com/forums/5478101-post106.html a link to the only study that I am aware of on scuba equipment configurations and drag, done by the US Navy. How many of you have read it? Or do you just accept that BCs cause (significantly) more drag on faith? Have you read any different, possibly conflicting studies? Please report them!

Those who understand drag physics know that frictional opposition to motion in water is a function of many factors, but it always increases with velocity. In some circumstances someone swimming slowly in a BC will experience less drag than someone swimming rapidly in a BP/w.

According to the above study, someone swimming in a wetsuit with face mask, snorkel, and weights experiences twice the drag of someone swimming in trunks only at 1 ft/s. Someone in a full scuba outfit with a single tank experiences three times the drag of someone swimming in trunks only at 1 ft/s. Double tanks? Four times the drag of someone swimming in trunks only at 1 ft/s.

I don't see anyone telling divers that they should avoid doubles because of the drag...

After all, common sense tells us that heavier objects fall faster than lighter objects. Try the experiment and get back to me...

Don't get me wrong - I have nothing against BP&W. I just don't like magical properties being ascribed to them.

Streamlining issues of bp/wing that I feel are significant to my typical dive sites:

• We have significant drift currents in Palm Beach, and there are frequently situations where I may want to go cross current, or up current
  • as in spotting a lobster hotel crosscurrent or upcurrent
  • as in seeing a turtle or other marine life I want to shoot video of cross-current or upcurrent
• If I need to go upcurrent or cross current, the "smart" way is to go "belly to the bottom". Having a stab jacket type BC will typically add lots of areas on your chest that can snag the bottom, and this is worsened by the traditional configurations and routings used on this form of jacket ( for consoles, octopus, etc).
• A bp/wing like a Halcyon, allows you to space yourself an inch off the bottom, and has no snagging points all over your ventral surface like a jacket bc....in the early nineties I was forced by diveboats to use vests like the scubapros and other jackets( they would not let you dive with just a harness as in the old days), and the memory of how poorly they performed in "bellying to the bottom" is still fresh in my mind. From the moment I tried my first Halcyon, and skimming along the bottom became easy again, I would never use a jacket style BC again ( on purpose
• I understand most divers glory in going slow, so swim speed is a joke to them. However, if you do need to beat a big current, swim speed is not the joke most would pretend it is. A diver wearing a DIR style Halcyon type bp/wing will have a smaller profile in the water than the jacket wearer....as with the stats showing the swim trunks are faster than wetsuit and tank, or that single tank is faster than doubles.....I can beat big currents much better with the halcyon approach than with a jacket approach....this can be demonstrated with a Gavin scooter pulling the same diver in either configuration( bp or jacket) up current or cross current, and this will remove the element of the diver's potentially changing propulsive power ( tired legs and , it is a great enough difference for a diver like myself to "feel" a large jump in speed witht he bp/wing, and to also experience a much shorter time spent attempting to arrive at an upcurrent or cross current destination.
• I don't need a "scientist" to tell me which is faster. This "presumption" is extremely irritating.....
  • I also don't need a "scientist" to tell me that Statin drugs are safe ( the "scientific method" or a sham of it, was used to make billions on people trusting the "scientists" at the expense of their own health)
  • I don't need a scientist telling people that his studies show that the alleged bone building drigs such as fosamax or actonel have been shown conclusively by science to be good for people--when we know the reality is that they are a massive fraud and destructive to the public health..
  • The public needs to understand the principles of science, to assist in their own common sense evaluation....listening to someone preaching about studies is statistically more likely to end up being a sales creation by a company with a vested interest, with science the uncaring prostitute.

 

[Splitlip]

We'll talk about BCs adding "pounds" of lift later on...

Rodale's scuba lab has been testing BCD's for years. I've been reading the reports since '03. The inherent buoyancies ranged from <1 to >5 pounds. So up to 5 or 6 # additional ballast need to offset the worst case. The inherent buoyancy of my SS rig is ~ <7 #.

I know we are talking inherent buoyancy, bet let's take a look at something else.

I just weighed my daughter's SP BC in size small. about 7.5 pounds which is about the same as my steel BPW . My BPW however is about 7 # negative.

Now if I were to dive my daughter's BCD and wanted to achieve the same buoyancy I get with my wing, I would need to add at least 7 # of lead plus a couple for the inherent buoyancy bringing the total surface weight of the BC up to ~ 16 pounds; roughly twice my BPW.

Here is a link to Scuba lab BC tests. Gear / BCs | Scuba Diving

 

[Scott L]

The jacket BCD crowd is apparently highly susceptible to mass marketing campaigns. They apparently have no objections with considerable tank instability along with nearly suffocating tightness when units are fully inflated. These giant sea-anchors create plenty of unnecessary drag as compared by their much more streamline cousins (BP/W's). also add in less durability, and far less functionality.

Go ahead, boys and girls, continue to be manipulated by bigger named corporate manufacturers. Meanwhile, we will be cutting through the Fla waters with the greatest of ease with plenty of gas left for longer dives...

 

[BDSC]

The jacket BCD crowd is apparently highly susceptible to mass marketing campaigns. They apparently have no objections with considerable tank instability along with nearly suffocating tightness when units are fully inflated. These giant sea-anchors create plenty of unnecessary drag as compared by their much more streamline cousins (BP/W's). also add in less durability, and far less functionality.

Go ahead, boys and girls, continue to be manipulated by bigger named corporate manufacturers. Meanwhile, we will be cutting through the Fla waters with the greatest of ease with plenty of gas left for longer dives...

I'm assuming this was a "tongue-n-cheek" post cause I know you're smarter than this!

 

[MauiScubaSteve]

Tell me if I have this correct:

...

5. Many scubaboard posters say that the bp/w is less bulky, more streamlined, has better trim, better weighting, better venting than non bp/w and tell this to new divers.
6. OP is irritated that many scubaboard posters provide anecdotal evidence of this nature to support their contentions.
7. OP doesn't like many scubaboard posters do this even though the retail scuba industry does this for their equipment.

...

What is wrong with posters on scubaboard promoting an alternative viewpoint from their own experience compared to the retail dive industry?

Many BP/W proponents here on SB evidently state their anecdotal opinion as if it were fact. The reason I say "evidently" is that I have a strong feeling some of the BP/W proponents here on SB make the exact same statements as if they were fact without even having a true comparative opinion, just repeating something others have ignorantly stated as fact.

Many people who make the change to BP/W may have started diving in a Vest and not been good divers. They may have been using a Vest that was badly designed, or just not designed well for their particulars. The first dives are a learning curve and then after getting better at diving they change to a BP/W, hopefully after good research and personal tests to find a proper BP/W for their particulars.

I think it is highly likely that if similar research and testing were done to find a Vest that fit their particulars, the person would also feel faster in the water than they did back in the old gear, earlier in the learning curve.

I have also pointed out when opinionated people make absolute statements of fact that are unsupported ignorance.

BP/W's are more streamlined than Vest BC's

and

BP/W's vent easier than Vest BC's

are both

UNSUPPORTED IGNORANCE !!!

BP/W's are more streamlined than Vest BC's

A bind man could determine that BP/W's are more streamline thereby creating less drag...

BP/W's vent easier than Vest BC's

Unless some fool retro-fits with a SS1 or Air2 gizmo...

Here is someone who is evidently very opinionated, and also types ignorant, unsupported statements of fact.

There have been no studies comparing the drag of a BP/W to the drag of a Vest, much less any studies that compared the drag of all BP/W to the drag of all Vests!

There have been no studies comparing the venting of a BP/W to the venting of a Vest, much less any studies that compared the venting of all BP/W to the venting of all Vests!

For now, let's just compare two frontal views of single tank divers, with regards to each BC's drag (not counting hose routing, just the BC's);

​

A blind man is who I think types...

"BP/W's are more streamline thereby creating less drag"

 

[Scott L]

Well, I guess GUE, UTD, TDI, IANTD and 50K+ tec divers have it all wrong.

 

[Kern]

Just for fun, show me 2 photos from the same distance & angle.

 

[BDSC]

Going by those two pictures the vest wins hands down. :thumbs-up