Jacket inflate vs Back inflate

[tbone1004]

We still teach bare tank breathing... It's always nice to know you can swim around with just a tank and a mask and look good.
That's about as basic as it gets

 

[Tropicalwolf]

Back inflate

 

[elmer fudd]

It's funny, back when I started diving the basic rig was a moulded plastic back pack with either a single or a dual tank mounting band that clamped the bottle firmly to the pack. It used 2 shoulder straps and a waste strap that latched. We used a horse collar basically for surface flotation or you could orally inflate it a bit underwater. We wore a weight belt that was donned after all other gear was in place so you could ditch it easily. And after maybe 20- 30 years later and 4 million versions of user friendly flotation devices created basically for creature comfort so many people want to basically go back to the beginning. Of course the wing is an add on to the original.

I actually have one of those, and I use it. I filled it up with lead shot though to get some weight off my belt and to better distribute it. It holds 10.5 lbs of lead inside. It makes a fantastic backplate for diving with a double hose regulator as I can mount the tank a few inches lower than I can with my modern backplate.

 

[Dyno Bill]

I had two of them, not sure where they got to but I used one for years cleaning boat bottoms without weight.

 

[danvolker]

The vast majority of dives made in the world are made in warm water. For the most part, the divers who make at least a hundred dives every year live in warm water regions. Extrapolating that majority of experienced divers to a guess as to which BC is more common would seem to favor the most common BC used in warm water.

Here in Hawaii the vast majority of experienced divers use vest BC's. We do see a fair number of BI's but there is no way most experienced divers we see here are using BI. From what I read about other warm water locations, Hawaii is typical.

As far as the Op is concerned, in California the % of BI BC's is probably higher than in the whole world.

I think this is related to far more diving in places with virtually no "challenge" from big currents or other harsh environmental conditions...In Palm Beach, Fl where I do most of my diving, you see Most divers on charter boats drifting with the current and riding effortlessly down the reef....this is a place where the recreational level dives take very little skill or athleticism to enjoy easily....However, the TYPICAL new diver with jacket style BC will be swimming head up and feet down....this is pathetic as a byproduct of lazy instruction--trim "should have" been addressed and weighting perfected prior to issuance of c-card. The jacket-style bc is harder to obtain a perfect horizontal trim/swimming position, but it absolutely CAN be accomplished.

On our deeper Palm Beach reefs or deep wrecks, currents can be a real challenge, even for strong highly skilled divers. Here, back plate and wing use will provide a very large advantage over the high drag and poorer trim of the jacket style bc. I was just on such a dive last week - on one of Jim Abernethy's boats...he had some of underwater photography's biggest guns on his boat, for a Jewfish photoshoot. Shooters incuded Wyland, David Doubilet, and at least 6 other highly skilled photographers. The current on the wreck we were on for dive number 2 was huge. It was probably over 3 mph, and there were huge Eddie effects near any structure you would pass over. With my backplate and wing setup (Halcyon w/27 lb wing), I could skim inches on top of the bottom, where skin friction drag massively attenuates the current speed your body is in contact with. If I had been using a scuba pro stab jacket, I would have had a much harder time slipping through the fast water, as the drag differences are significant, and the ability to swim belly to the bottom are bigger still.
The bonus for being able to follow Jimmy on a dive like this, ( he uses a halcyon plate and wing also by the way)....is that Jimmy will ALWAYS get to the REAL action. We were able to move through insane currents and eddies, to get into a large opening at the bottom of this wreck, where one of the most massive concentrations of baitfish I had ever seen were exploding in and out of....the density of baitfish was so high, that as we swam about 6 feet into this compartment, we could only see about 1 foot ahead, due to the near solid mass of pulsating baitfish. You would stick your arm into it, and your arm would disappear! After a few minutes of watching the pulsating mass of baitfish, I waved my hand vigorously in front of me, and about 2feet of baitfish cleared for a couple of seconds--at which time I was able to see a 6 foot long jewfish lying down on the bottom directly in front of me. The big guns were lying down on the bottom, cameras on tiny tripods--essentially anchoring themselves to the bottom by escaping the current in this manner. The shots they were getting will have to be fantastic...but the skills and gear required were far beyond that typical of new divers.

My point....yes you can dive a jacket bc and enjoy it. But if you want BIG ADVENTURE, you would be better off starting with a bc (read as backplate and wings) that will help you be "all that you can be"....
I could come up with dozens of scenarios where getting yourself maximally slick in the water, with optimal horizontal glide potential, would be much better for getting the experience you want.....so..get the Backplate and wing!

Regards,
DanV

 

[Dyno Bill]

I think this is related to far more diving in places with virtually no "challenge" from big currents or other harsh environmental conditions...In Palm Beach, Fl where I do most of my diving, you see Most divers on charter boats drifting with the current and riding effortlessly down the reef....this is a place where the recreational level dives take very little skill or athleticism to enjoy easily....However, the TYPICAL new diver with jacket style BC will be swimming head up and feet down....this is pathetic as a byproduct of lazy instruction--trim "should have" been addressed and weighting perfected prior to issuance of c-card. The jacket-style bc is harder to obtain a perfect horizontal trim/swimming position, but it absolutely CAN be accomplished.

On our deeper Palm Beach reefs or deep wrecks, currents can be a real challenge, even for strong highly skilled divers. Here, back plate and wing use will provide a very large advantage over the high drag and poorer trim of the jacket style bc. I was just on such a dive last week - on one of Jim Abernethy's boats...he had some of underwater photography's biggest guns on his boat, for a Jewfish photoshoot. Shooters incuded Wyland, David Doubilet, and at least 6 other highly skilled photographers. The current on the wreck we were on for dive number 2 was huge. It was probably over 3 mph, and there were huge Eddie effects near any structure you would pass over. With my backplate and wing setup (Halcyon w/27 lb wing), I could skim inches on top of the bottom, where skin friction drag massively attenuates the current speed your body is in contact with. If I had been using a scuba pro stab jacket, I would have had a much harder time slipping through the fast water, as the drag differences are significant, and the ability to swim belly to the bottom are bigger still.
The bonus for being able to follow Jimmy on a dive like this, ( he uses a halcyon plate and wing also by the way)....is that Jimmy will ALWAYS get to the REAL action. We were able to move through insane currents and eddies, to get into a large opening at the bottom of this wreck, where one of the most massive concentrations of baitfish I had ever seen were exploding in and out of....the density of baitfish was so high, that as we swam about 6 feet into this compartment, we could only see about 1 foot ahead, due to the near solid mass of pulsating baitfish. You would stick your arm into it, and your arm would disappear! After a few minutes of watching the pulsating mass of baitfish, I waved my hand vigorously in front of me, and about 2feet of baitfish cleared for a couple of seconds--at which time I was able to see a 6 foot long jewfish lying down on the bottom directly in front of me. The big guns were lying down on the bottom, cameras on tiny tripods--essentially anchoring themselves to the bottom by escaping the current in this manner. The shots they were getting will have to be fantastic...but the skills and gear required were far beyond that typical of new divers.

My point....yes you can dive a jacket bc and enjoy it. But if you want BIG ADVENTURE, you would be better off starting with a bc (read as backplate and wings) that will help you be "all that you can be"....
I could come up with dozens of scenarios where getting yourself maximally slick in the water, with optimal horizontal glide potential, would be much better for getting the experience you want.....so..get the Backplate and wing!

Regards,
DanV

Actually at least for me the BIG ADVENTURE didn't start until I left the scuba gear on the boat and started to freedive to hunt. There are several short videos at you tube depicting some freedive stunts that are really exciting.

 

[danvolker]

Actually at least for me the BIG ADVENTURE didn't start until I left the scuba gear on the boat and started to freedive to hunt. There are several short videos at you tube depicting some freedive stunts that are really exciting.

I love free diving as well. While getting rid of stab jacket drag by switching to halcyon bp/wing was a big improvement, as a Freediver with ultra slick Freediver wet suit and carbon fiber C4 Freediver fins, You really can glide like you belong in the ocean. For Boynton Beach dives where the crown comes up to 40 feet, and bottom of inshore ledge is rarely deeper than 60 feet, freediving can be a great way to FEEL big adventure. Unfortunately for me, I get more excited by seeing the BIG marine animals, and they tend to show up on the offshore sides of reefs at depths over 80 feet...or on wrecks deeper than 80 feet....some of the most spectacular sights of big animals has been at 125 to 145. That's too deep for me to Freediver, so I have to make due by borrowing as much of my free diving "slickness" as possible, in gearing myself for the deeper scuba dives.


I would also say that if a new diver learns to Freedive along with scuba, they will rapidly gain an epiphany on drag and trim effects of bulky bc junk. As a Freediver, they will immediately feel the "real" glide after a big slow kick, they will enjoy the nice coasting phase of the long glide, and when they do A/B comparison of jacket bc and bp/wing, they will immediately prefer the drastically increased glide potential of the bp/wing

 

[MauiScubaSteve]

OK, let me get this straight; famous photographers (and Wyland) need to have streamlined BC's?

Did said famous photographers (and Wyland) have dual strobe dSLR's?

It is very likely that a big reason there have been no studies on BC Cd's is that if you look at the whole package; changing the BC has very little impact on a diver's overall Cd.

First there is the human, then the tank, and the reg set. That is significant drag. Trim makes way more difference than any BC.

Then I have to ask if any of those famous photographers (and Wyland) with dual strobe dSLR's made headway into that huge current? If they got their camera rigs up current there is no way it was 3 mph, and no way a well designed vest BC couldn't have been right there in the mix.

I have a basic SeaQuest Spectrum vest BC that I bought in Waikiki 2/01 for $161 (closeout) to do zero to hero in Key Largo. This vest BC also did CDS-NSS Cavern/Intro to Cave at Peacock/Olsen, 4 years of guiding/instructing Oahu/Maui and hundreds of BIG ADVENTURE personal dives.

I have the scooters and I am challenging any and all comers to put your money where your mouth is. Come to Maui and we will race scooters. After I pull away from you we will trade scooters and then see if I pull away from you slower or faster.

 

[danvolker]

OK, let me get this straight; famous photographers (and Wyland) need to have streamlined BC's?

Did said famous photographers (and Wyland) have dual strobe dSLR's?

Yes. And I did NOT say that they ALL got to the wreck. A few made it, after Jimmy and I had been there for a while. The ones that did, made it by good current skills---swimming/pulling along the sandy bottom ( with rocks) , keeping their bodies out of the current. Jimmy Abernethy was the fastest of the photographers, and he WAS using a Halcyon bp/wing. In all fairness though, Jimmy is known far and wide as being able to move unlike a human, underwater.

It is very likely that a big reason there have been no studies on BC Cd's is that if you look at the whole package; changing the BC has very little impact on a diver's overall Cd.

First there is the human, then the tank, and the reg set. That is significant drag. Trim makes way more difference than any BC.

Studies would likely have been paid for by some large manufacturer anyway, and been biased, and worthless, exactly like most gear tests done by Rodales and other mags.
If you live and dive in a high current environment, and you dive long enough, you will try many different gear sets. In the 80's and early to mid 90's I used SeaQuest and Scubapro jacket BC's, as well as occaisionally an AT Pac. When I met several of the WKPP divers on a high current deep wreck, their ability to be slick in the water impressed me so much that I bought a Halcyon bp/wing soon after, and found I had a kick and glide much more like I had back in the early days before I used Seaquest or scubapro--back when I just used a tank with shoulder straps and no BC ( a set up I still remember fondly, for diving with lycra ). The kick and glide of the Halcyon set up was partly the tiny 17 pound lift wing having almost no drag--there was very little profile of the small wing to expose to the water. Also crucial in the low drag, was "the kind of hose routing" you are suppossed to use with the bp/wing. Unlike "typical" jacket BC wearers who have a long pressure guage with huge console trailing behaind as they swim, or stuffed on top of their chest, drawing an extra 6 inches of draft, the DIR set up for BP/wing has a very streamlined routing of reg hoses and a short pressure guage hose with no console and no boot....there is very little drag in this system when compared to typical jacket BC set ups. While a small profile Jacket BC user could try to approximate a DIR hose routing set up, and this WOULD make them much more streamlined, it would be hard on most designs to route the long hose under a pocket or knife pocket in the correct place to hold the long hose in the normal position.
See photo in ...

http://www.sfdj.com/spring/dir2.jpg
I use a knife sheath where the large pocket is on the photo, to route under..or, a light canister when required by the dive.
In the photo, you can see how the gear config allows the diver to essentially " belly to the bottom" without getting snagged by the console or other stuff on the ventral surface of the jacket bc user.

Then I have to ask if any of those famous photographers (and Wyland) with dual strobe dSLR's made headway into that huge current? If they got their camera rigs up current there is no way it was 3 mph, and no way a well designed vest BC couldn't have been right there in the mix.

I was with Jim, and began seeing strobes going off about 5 minutes after Jim and I settled into a compartment. We had done an entire circumnavigation of the wreck, while the 2 or 3 photograpers who made it to the compartment, went straight into the compartment --perhaps they had been here before, or perhaps they saw our bubbles coming out---the bait fish were so dense there was no way for me to see anyone coming in. I think 2 photographers were in the compartment in the 5 inutes or so after we settled, and one more showed up quite a while later--Ryan from Reef Photo.
As I said, even for a slick diver without camera, swimming would not be the way to move against this current--the only viable technique was to hug the bottom, and use hand holds from rocks or sand to move upcurrent.
I also saw big camera set ups sitting by themselves a few times during this 45 or so minute dive--indicating to me the owners were doing recon and did not want to fight the current with the camerta rig.

I have a basic SeaQuest Spectrum vest BC that I bought in Waikiki 2/01 for $161 (closeout) to do zero to hero in Key Largo. This vest BC also did CDS-NSS Cavern/Intro to Cave at Peacock/Olsen, 4 years of guiding/instructing Oahu/Maui and hundreds of BIG ADVENTURE personal dives.

This looks like the SeaQuest that I used to have. For a Jacket BC it is relatively low drag--you must admit, there are MANY Jacket BC's that are huge, making the diver more like a "puffer fish"....While the Seaquest spectrum is much lower drag than most BC's, it still is difficult to route hoses along it DIR stle....and for scootering, I would want a crotch strap and scooter tow ring ( like I have on my Halcyon). If you have a fast scooter ( like the Gavin I sometimes use), you do not want to try to hold yourself with the handles..you want to have the scooter pulling you from the crotch ring, and have the muscles in your arms totally relaxed, and your heart rate down to 60 bpm or lower ( unlikely if your arm muscles are exerting to hold on to a fast scooter). With DIR scootering, your arms have near zero work load, and steering is effortless.

I have the scooters and I am challenging any and all comers to put your money where your mouth is. Come to Maui and we will race scooters. After I pull away from you we will trade scooters and then see if I pull away from you slower or faster.

I could make the same offer, here in Palm Beach , Fl .
The difference is, if you come here, and I lose the scooter race, I will pay your airfare! .... Read that as I am pretty sure I will win

 

[Crush]

Why is it that back inflates would be more popular in cooler water?

Here are my opinions, based upon my experiences:

1. I found that the jacket style BC which I rented pressed in on my stomach and waist when inflated, making it uncomfortable to breathe. Before anyone jumps in and posts "you must be fat," "you were overweighted," (neither is correct) or "you should hardly need to put any air into your BC" I will respond with "you must be a warm water diver and the OP is in California (not warm water)." I dive cold water. When diving a 7 mm two-piece wetsuit you will have considerable compression at depth (on the order of 20# for me), meaning that you need to put a considerable amount of air into the BC to keep you neutral. In my case, for the BC I was wearing, this lead to uncomfortable pressure on my waist and ribcage, making breathing more difficult. I am sure that jacket style BCs are great in warm water. However, in cold water I very much prefer my rear-inflate BC (Zeagle Scout).

2. I used to feel that my rear-inflate BC "pushed me forward." I now believe this to be incorrect - I think that my weights on my weight belt were incorrectly positioned (too far forward), the result being that the weight pulled me forward. Having repositioned the weights (including having moved some to my top cam band) I find that (with my rear-inflate BC) I float comfortably in an upright position with no tendency to face-plant.