Inflator question

[Foo]

Okay, don't flame me if this has been asked over and over again. I don't know what to call it in order to do a search.

A couple of weeks ago, I used a weight-integrated bc for the first time. I mean, every time I've ever been in scuba gear, from pool work to ocean, has been with a weight belt. I really loved the w.i., it felt so different. Even my fins became super-turbo powered with the w.i., I got much more thrust with less effort (am I crazy?) I'm now investigating what type of b.c. to get.

The one that I borrowed had the type of inflator that doesn't have a hose that you lift to dump air. It was a unit that was attached to the left side of the jacket, and my l.p. hose just hooked up to it. There were two buttons, one for the inflate, one to dump. It took a little getting used to, but I think that I liked it. Any opinions out there regarding these inflators? I don't know what they're called, exactly, sorry.

Foo

 

[hecker-the-wrecker]

I believe it's a mares b.c. and they call it "airtrim" I have heard some negative comments, mostly from people who have never tried it. I thought the idea was great. I really think you should be able to dump air in any position without holding the hose over your head.I regret buying my b.c. without having the opportunity of trying one.

 

[Firefyter]

Mares makes the airtrim, and Cressi has the flight control (IIRC). My wife's BC has the airtrim, and she loves it. Do a search for airtrim and you should find a bunch on it. Like Hecker said, though, keep in mind that most of the critics never tried it.

 

[Foo]

It was a Dacor brand b.c., perhaps called Nautica? Then last weekend, at the TSP Trashure Hunt, I tried the new Mares limited edition with the airtrim feature. I had weighting problems there, though- we put 6 lbs of my weight in trim pockets that turned out to be non-pockets. The Mares rep was there, in the water with me, we couldn't for the life of me figure out why I couldn't descend... we kept adding weight till you could sink a horse. What we didn't realize, is that the back trim weights had slipped out and will be found this summer by a kid who will yell, "Look! I found a beanbag!" Timeliner found this to be particularly entertaining, so I thought I'd save him the trouble of telling off on me. ;o)

I didn't want to have problems during the treasure hunt, so I went back to my trusty US Diver's BC and weight belt. I was glad I had thrown them in, just in case. But I'm now anxious to try some w.i. bc's, and start learning how to use them. It was a strange sensation, like I was lighter. I kept a close eye on my depth gauge, which was easy, since I was using my compass doing navigation in a valid Texas swamp.

Thanks for the info on the Airtrim name. I remember that now, I think it's printed on the bc somewhere. I'm going to have to try it a few more times to be certain that I would be happy with it. ScubaSteve is good about letting me try before I buy. Of course, he does know that once I try, I will buy. LOL. The one that I used turned out to have a hole in it, so I was losing air and kept having to adjust while trying to do a bouyancy control dive for AOW. Note to self: Don't purposely task overload yourself!

Foo

 

[ParamedicDiver1]

Have used on before, the Seaquest Fusion, had the inflator on the left lower side and the oral inflator hose in a little side pocket. It was very nice. Here is an excert from an article about the new inflator style.

http://www.divernet.com/equipment/0704divertests.shtml
...the original BC, the ABLJ or Adjustable Buoyancy Life-Jacket. You wore it and put air into it as you went deeper, releasing that air again on the way up. Why did those early bottom-scratchers find this to be such a problem?
How did you put the air in? You took a breath from your regulator and blew it via a hose into the ABLJ. How did you release air? You raised the hose to the highest point and trickled it out. The hose was corrugated to make it more manoeuvrable.
With drysuits you can control your buoyancy in a similar way. You put air in on the way down, via a direct-feed hose from your main air supply, and you trickle it out either by way of a cuff-dump or a constant-volume dump on the way up.
So why do we need a corrugated hose on a BC if we don't need one on a drysuit?
The fact is that makers of BCs supplied corrugated hoses only because ABLJs had them. ABLJs had them because they were included before direct-feeds were thought of.
But no manufacturer was brave enough to supply an ABLJ without a corrugated hose, even if they realised it was unnecessary. Conservative-minded divers would not have bought it, and even today most instructors teach their trainees to use their BC as if they had an early ABLJ, raising the hose to dump air. Why, when they have efficient dump valves fitted?
Welcome to the 21st century. Goodbye corrugated hose. Hello a whole range of BCs that use the same mechanisms as a drysuit.

 

[DA Aquamaster]

...and even today most instructors teach their trainees to use their BC as if they had an early ABLJ, raising the hose to dump air. Why, when they have efficient dump valves fitted?
Welcome to the 21st century. Goodbye corrugated hose. Hello a whole range of BCs that use the same mechanisms as a drysuit.

As a tech, each year I see a few BC's come in the shop after the diver has yanked on the dump valve assembly so hard that they managed to break it off. With a dump valve mounted high on the bladder, a failed valve or a broken fitting means rapid and total air and bouyancy loss.

With an early horse collar type BC with either a manual or oral inflator on the end of a corrogated hose, the hose was long enough that even if the inflator was missing, the open end of the hose would be low enough to trap a usable amount of air in the BC.

With a shoulder mounted dump valve, you are placing a lot of trust in the integrity of the valve. When Scubapro introduced their stab jacket in the 70's they used a shoulder mounted dump with a separate pull cord running through a guide which made it virtually impossible for an excited or panicked diver to break the valve. This was a good compromise.

However today a shoulder mounted dump at the base of the corrogated hose and activated by pulling on the corrogated hose is common. Since the fitting is plastic, breakage can and does occur. So there is in my opinion a valid reason for instructors to teach students to dump by raising the corrogated hose rather than pulling on the corrogated hose.

If you look at techical divers and modern day wings, you will find a dump valve/overpressure relief valve low on the bladder that is used to vetn air in a normal swimming position and a corrogated hose that is used to dump air when vertical on the surface, but no shoulder mounted dump valve at all. This approach is in many ways a return to the older and simpler horse collar inflate/dump approach in that no shoulder dump is involved. It offers the same benefit in terms of reduced potential for failure and the ability to trap adequate air in the bladder in the event the dump valve fails.

Personally, I have always felt simpler is better and I don't think the whole HUB, Airtrim, IIRCs approach is the direction to take. It adds more complexity to what should be very simple system.